Equilibrium and kinetics of surfactant adsorption

EQUILIBRIUM AND KINETICS STUDIES OF
INTERACTION BETWEEN
SURFACTANTS, WATER, BIOPOLYMERS AND
SOLID-LIQUID INTERFACES
THESIS SUBMITTED FOR THE DEGREE OF
DOCTOR OF PHYLOSOPHY (SCIENCE)
OF
JADAVPUR UNIVERSITY
CALCUTTA
BY
SAMARESH CHANDRA BISWAS
DEPARTMENT OF FOOD TECHNOLOGY
AND BIOCHEMICAL ENGINEERING
JADAVPUR UNIVERSITY
1997

(iii)
Declaration
I hereby declare that the work embodied in the present thesis has been
carried out by me in the Department of Food Technology and Biochemical Engineering,
Jadavpur University, under the supervision of Prof. D.K. Chattoraj, D.Sc., Ph.D, FNA
and that the work or any part thereof was never submitted for any award of degree or
diploma.
(SAMARESH CHANDRA BISWAS)
Protein Chemistry Laboratory
Department of Food Technology
and Biochemical Engineering,
Jadavpur University,
Calcutta-700 032
INDIA.

(iv)
CERTIFICATE FROM THE SUPERVISOR
This is to certify that the thesis entitled “Equilibrium and Kinetics Studies of
Interaction between Surfactants, Water, Biopolymers and Solid-Liquid Interfaces”
submitted by Sri Samaresh Chandra Biswas who got his name registered on 17th
May,
1994 for the award of PhD (Science) degree of Jadavpur University, is absolutely based
upon his own work under the supervision of Prof. D. K. Chattoraj and that neither this
thesis not any part of its has been submitted for any degree/diploma or any other
academic award anywhere before.
Signature of Supervisor and
date with Official seal
Prof. D. K. Chattoraj, FNA
INSA Senior Scientist
& Biochemical Engineering
JADAVPUR UNIVERSITY
CALCUTTA -700032

(v)
ACKNOWLEDGEMENT
The present thesis records the results of the study of “Equilibrium and Kinetics
Studies of Interaction between Surfactants, Water, Biopolymers and Solid-Liquid
Interfaces”. The experimental work has been carried out by me in the Protein Chemistry
Laboratory, Department of Food Technology and Biochemical Engineering, Jadavpur
University, Calcutta under the direct supervision of Prof. D. K. Chattoraj, D.Sc., Ph.D.,
FNA formerly Professor and presently INSA Senior Scientist of this department. I
express my sincere gratitude to him for his constant encouragement, valuable advice and
constructive discussion in preparing this thesis.
I acknowledge with thanks the help and suggestions received from Prof. D. C.
Mukherjee, Calcutta University, Prof. S. P. Moulik, Department of Chemistry, Jadavpur
University and Dr. K. P. Das, Department of Chemistry, Bose Institute.
I express my thanks to Mr. S. K. Biswas, Ms. S. Biswas, Ms. Sraboni Roy, Dr.
(Ms) D. Sarkar, Ph.D., Dr. P. K. Mahapatra, Ph.D., Dr. (Ms) P. Banerjee, Ph.D., Dr. Sk.
A. Gani, Ph.D., Ms. N. Ghosh, M.Sc., Mr. E. Halder, M.Sc., Mr. A. Mitra, M.Sc. and
Dr.(Ms) S. R. Chatterjee, Ph.D. for their constant help and co-operation.
I acknowledge with thanks CSIR, New Delhi, India for financial assistance in the
form of CSIR (JRF and SRF) Fellowship. I also thank Department of Food Technology
and Biochemical Engineering, Jadavpur University for providing the infrastructure
facilities for carrying out the present work.
Finally, I am greatly indebted to all the members of my family who have always
encouraged me in my academic pursuits. Without them this endeavor would not be
completed.
(SAMARESH CHANDRA BISWAS)
Protein Chemistry Laboratory
and Biochemical Engineering,
Jadavpur University,
Calcutta-700 032
INDIA.

(vi)
C O N T E N T S
Particulars Page No.
List of Tables (viii)
List of Figures (x)
List of Important Symbols (xiii)
List of Units (xvii)
List of Abbreviation (xviii)
CHAPTER 1: Introduction
• Binding Interaction in bulk 1
• Adsorption at Interfaces 1
• Biopolymers and Biosurfaces 1
• Surfactants and Micelles 4
• Binding of Ligand to Biopolymers 5
• Adsorption of Surfactants at Solid-Liquid Interface 7
• Water-Biopolymer Interactions and Excess Hydration 9
• Adsorption Liquid-Vapor and Liquid-Liquid Interfaces 10
• Equilibrium Adsorption of Proteins at Solid-liquid Interfaces 12
• Desorption Phenomena 14
• Thermodynamics of Adsorption at Different Interfaces 15
• Kinetics of Adsorption from Liquid Phase 18
• Kinetics of Adsorption at Liquid-Vapor and Liquid-Liquid
Interfaces
19
• Kinetics of Adsorption at Solid-liquid Interfaces 21
• Kinetics of Adsorption of Surfactants at Solid-Liquid Interfaces 22
• Scope of the Work 23
• References 25

(vii)
CHAPTER 2: Polysaccharide-Surfactant Interaction Part-1, Adsorption of
Cationic Surfactants at Cellulose-Water Interface
• Introduction 40
• Materials and Methods 41
• Results and Discussion 42
• References 60
CHAPTER 3: Polysaccharide-Surfactant Interaction Part-2, Binding of
Cationic Surfactants to Carboxymethyl Cellulose and Dextrin
• Introduction 62
• Materials and Method 63
• References 86
CHAPTER 4: Kinetics of Adsorption of Cationic Surfactants at Silica-
Water Interface
• Introduction
• Materials and Methods
• Results and Discussion
• References
88
89
91
111
CHAPTER 5: Kinetics of Adsorption of Cationic Surfactants at Charcoal-
Water Interface
• Introduction 114
• References 134

(viii)
CHAPTER 6: Kinetics of Desorption of Proteins from Protein-Coated
Surfaces of Silica and Charcoal by Various Desorbing Agents
• Introduction 135
• References 158
Summary 160

(ix)
LIST OF TABLES
Table
No.
Description Page
No.
2.1 Values of azeo
C2 , n1 and n2 for adsorption of cationic Surfactants at
cellulose-water Interface.
52
2.2 Parameters for adsorption of cationic surfactants at Cellulose-water
Interface.
53
2.3 Thermodynamic Parameters for adsorption of cationic Surfactants at
Cellulose-water Interface.
54
3.1 Values of azeo
C2 , n1 and n2 for binding of cationic surfactants to Na-
Salt of carboxymethyl Cellulose.
73
3.2 Values of azeo
C2 , n1 and n2 for binding cationic surfactants to dextrin. 74
3.3 Parameters for binding of cationic surfactants to carboxymethyl
cellulose (CMC).
75
3.4 Parameters for binding of cationic surfactants to dextrin. 76
3.5 Thermodynamic Parameters for binding of CTAB to Na CMC and
dextrin.
77
4.1 Kinetic rate constants for adsorption of cationic surfactants at silica-
water interface.
99
4.2 Kinetic rate constants for adsorption CTAB at silica-water interface in
presence of different salts and urea.
100
4.3 Activation energy parameters for adsorption of cationic surfactants at
silica-water interface.
101
4.4 Diffusion co-efficient (Ds) of cationic surfactants at silica-water
Interface.
102
5.1 Kinetic rate constants for adsorption of cationic surfactants at Charcoal-
water interface.
121

(x)
Table
No.
Description Page
No.
5.2 Kinetic rate constants for adsorption of CTAB at Charcoal-water
interface at different physicochemical conditions.
122
5.3 Activation energy parameters for adsorption of cationic surfactants at
Charcoal-water interface.
123
5.4 Diffusion co-efficient (Ds) of cationic surfactants at Charcoal-water
interface.
124
6.1 Kinetic parameters for desorption of Lysozyme from protein coated
Solid surfaces in presence of different desorbing fluids.
147
6.2 Kinetic parameters for desorption of -lactoglobulin from protein coated
solid surfaces in presence of different desorbing fluids.
148
6.3 Kinetic parameters for desorption of bovine serum albumin (BSA) from
protein coated solid surfaces in presence of different desorbing fluids.
149
6.4 Kinetic parameters for desorption of gelatin from protein coated solid
surfaces in presence of different desorbing fluids.
150
6.5 Activation energy parameters for desorption of proteins from protein
coated surface of silica and charcoal.
151
****************************************************************

(xi)
LIST OF FIGURES
Figure
No.
Description Page
No.
2.1 Plot of 1
2 vs C2 for adsorption of CTAB at cellulose-water interface. 55
2.2 Plot of 1
2 vs. C2 for adsorption of CTAB at cellulose-water interface
in presence of different neutral Salts and Urea.
56
2.3 Plot of 1
2 vs. C2 for adsorption of cationic surfactants of varied
hydrocarbon chain length at cellulose-water interface.
57
2.4 Plot of 0
apG vs. m
2
1
2 /  for adsorption of cationic surfactants at
cellulose-water interface.
58
2.5 Plot of G vs. m
2 for adsorption of cationic surfactants at cellulose-
water interface
58
2.6 Plot of ( 0
apG ) vs. 2/1 X for adsorption of cationic surfactants at
cellulose-water interface.
59
3.1 Plot of 1
2 vs. C2 binding of CTAB to CMC and dextrin. 78
3.2 Plot of 1
2 vs. C2 for binding of CTAB to CMC and dextrin. 79
3.3 Plot of 1
2 vs. C2 for binding of CTAB to CMC and dextrin. 80
3.4 Plot of 1
2 vs. C2 for binding of CTAB to dextrin in presence of
excess salts and urea.
81
3.5 Plot of 1
2 vs. C2 for binding of CTAB to dextrin in presence of
excess salts and urea.
82
3.6 Plot of 1
2 vs. C2 for binding of CTAB, MTAB and DTAB to CMC
and dextrin.
83
3.7 Plot of 0
apG vs. m
2
1
2 /  for binding of CTAB to CMC and dextrin. 84
3.8 Plot of  hiapG0
 vs. 2/1 X for binding of CTAB to CMC and dextrin. 85

(xii)
Figure
No.
Description Page
No.
4.1 Plot of 1
2 vs t for adsorption of CTAB at silica-water interface 103
4.2 Plot of 1
2 vs. time t for adsorption of CTAB at silica-water interface
in presence of neutral salts and urea.
104
4.3 Plot of 1
2 vs. time t for adsorption of CTAB, MTAB and DTAB at
silica-water interface.
105
4.4 Plot of 1
2 vs. time t for adsorption of DTAB at different
temperatures.
106
4.5 Best fit curve for adsorption of CTAB at silica-water interface. 107
4.6 Plot of –ln[ 1
22 e
] vs. time t for adsorption of CTAB at silica-water
interface.
108
4.7a Plot of –lnk1 and –lnk2 vs. 1/T for adsorption of CTAB at silica-water
interface.
109
4.7b Plot of –lnk1/T and –lnk2/T vs. 1/T for adsorption of CTAB at silica-
water interface.
109
4.8 Plot of H#
vs. –TS#
for adsorption of cationic surfactants at silica-
water interface.
110
5.1 Plot of 1
2 vs. t for adsorption of CTAB at charcoal-water interface. 125
5.2 Plot of 1
2 vs. t for adsorption of CTAB at charcoal-water interface at
different ionic strength.
126
5.3 Plot of 1
2 vs. t for adsorption of CTAB at charcoal-water interface at
different pH.
127
5.4 Plot of 1
2 vs. t for adsorption of CTAB, MTAB and DTAB at
charcoal-water interface.
128
5.5 Best fit curve for adsorption of CTAB at charcoal-water interface. 129
5.6 Plot of –ln [ 1
22 e
] vs. t for adsorption of CTAB at charcoal-water
interface.
130

(xiii)
Figure
No.
Description Page
No.
5.7 Plot of k1 and k2 vs. t
C2 for adsorption of CTAB at charcoal-water
interface.
131
5.8a Plot of –lnk1and –lnk2 vs. 1/T for adsorption of CTAB at charcoal-
water interface.
132
5.8b Plot of –lnk1/T and –lnk2/T vs. 1/T for adsorption of CTAB at
132
5.9 Plot of H#
vs. –TS#
for adsorption of cationic surfactants at
133
6.1 Plot of p vs. t for desorption of lysozyme from protein coated
surface of silica (Top) and charcoal (Bottom).
152
6.2 Plot of p vs. t for desorption of -lactoglobulin from protein coated
surface of silica (Top) and charcoal (Bottom).
153
6.3 Plot of p vs. t for desorption of BSA from protein coated surface of
silica (Top) and charcoal (Bottom).
154
6.4 Plot of p vs. t for desorption of gelatin from protein coated surface
of silica (Top) and charcoal (Bottom).
155
6.5 Plot of -lnp vs. t for desorption of lysozyme from protein coated
surface of silica and charcoal.
156
6.6 Least square fitting for desorption of lysozyme from silica surface. 157
****************************************************************

(xiv)
LIST OF IMPORTANT SYMBOLS
C2
t
initial molar concentration of solute in the bulk medium.
C2 molar concentration of solute after adsorption.
C2
azeo
molar concentration of solute at surface azeotropic state.
Cp
t
initial concentration of protein in gram percent.
Cp concentration of protein after adsorption.
2
1
extent of adsorption of solute per Kg or per sq. m. of adsorbent.
1
2
extent of adsorption of water per Kg or per sq. m. of adsorbent.
V volume in ml.
Vt
volume per unit weight or per sq. m. of adsorbent.
W amount of adsorbent.
A specific surface area in gm/m2
.
k1 and k2 first order rate constant for adsorption.
kd1 and kd2 first order rate constant for desorption.
Ea activation energy in KJ/mole for adsorption.
H#
enthalpy of activation in KJ/mole for adsorption.
S#
enthalpy of activation in KJK-1
mole -1
.
G#
free energy of activation for adsorption in KJ/mole.
Ed activation energy for desorption in KJ/mole.
Hd
#
enthalpy of activation for desorption in KJ/mole.
Sd
#
enthalpy of activation for desorption in KJK-1
mole-1
.
Gd
#
free energy of activation for desorption in KJ/mole.
 ionic strength.
k Boltzman constant.
h Plank’s constant.
R Gas constant.
T absolute temperature.
n moles of water, solute bound per Kg of solid.

(xv)
nt
total number of binding sites, moles of water or solute.
(SYMBOLS CONTINUED)
X mole fractions.
 surface pressure.
 boundary tension.
 Thickness of the thin layer of solvent adhered to the surface.
Ds diffusion co-efficient.
t time.
Gap apparent free energy change per Kg of the surface.
G standard free energy change per Kg of the surface.
0
BG Bull’s standard free energy change per mole of solute transferred
from the bulk solution to the surface.
**************************

(xvi)
LIST OF UNIT
Å Angstrom
nm nanometer
m meter
cm centimeter
ºC degree centigrade
ºK degree kelvin
mg milligram
KJ Kilo Joule
Cal calorie
ml mililitre
N normality
M molarity
Sec. seconds
hr. hour.
**********************

(xvii)
LIST OF ABBREVIATIONS
CTAB Cetyltrimethyl ammonium bromide.
MTAB Myristyltrimethy ammonium bromide.
DTAB Dodecyl trimethyl ammonium bromide.
SDS Sodium dodecyl sulphate.
CMC Carboxymethyl cellulose.
BSA Bovine serum albumin.
BLG -lactoglobulin.
cmc critical micelle concentration.
*********************

INTRODUCTION
Binding Interaction in Bulk
Matters in living as well as in non-living systems can be divided into three well
defined states- solids, liquids and gases. Each of these phases may form homogeneous
mixtures to form a single phase. Special interest in the present study is the interaction
between solute and solvent components within the aqueous phase. In all our studies the
solvent component is water. The solute components may be amphiphiles,
polysaccharides, proteins, urea, neutral inorganic salts and reagents used for preparing
buffer. Amongst these, polysaccharides and proteins are biopolymers or biocolloids.
Some of these also behave as macroions in solution depending upon the physico-
chemical conditions. Other components in the aqueous solution such as urea, neutral salts
are small molecules, whose direct interaction with biocolloid is not quite significant. On
the other hand long chain amphiphiles such as cetyltrimethyl ammonium bromide
(CTAB) may bind or associate with the biopolymers by hydrophobic, electrostatic,
chemical and other types of interactions in the aqueous phase. The solvent component
itself may also bind to these biopolymers forming hydrophilic colloids. In many
situations solvent and solute competes each other for binding interaction with
biocolloidal particles present in the aqueous phase.
Adsorption at Interface
The aqueous phase containing solute and solvent components may be in contact
with various types of immiscible solid, liquid or gaseous phases as a result of which an
interface between these immiscible phases is formed. The energy at the interface is higher
than that in the bulk medium. For this reason, the surfactants or amphiphiles in aqueous
phase compete with water for preferential accumulation at the interface. Such preferential
accumulation or interfacial binding is commonly known as adsorption.
Biopolymers and Biosurfaces
Biopolymers, which occur in living systems and take part in different biological
functions, are proteins, nucleic acids and polysaccharides.

(2)
Proteins constitute the largest fraction of living matter and occur in different
forms for the exhibition of different biological functions. Some proteins have specific
catalytic activity and functions as enzyme, while others serve as structural elements in
cells and tissues and still others are present in cell membrane and promote the transport
of certain substances into or out of the cells. Many other biological functions are served
by proteins. All the proteins are constituted from the same 20 different amino acids
through amide bonds in different sequence, called the primary structure, which is unique
and specific to each particular protein. The hydrogen bonding characteristics of the
polyamide bonds in the backbone of proteins results in secondary structures such as -
helix and -sheet. Intramolecular associations including ionic interactions, hydrogen
bonding and covalent disulphide bonds result in specific three dimensional orientation of
each polypeptide chain in space called the tertiary structure of proteins. Two or more
polypeptide chains, each with its own primary, secondary and tertiary structure, can
associate to form a multichain quaternary structure. Many proteins also occur in
conjugation with other nonprotein molecules called conjugated proteins. The fundamental
principles of protein structure and function are available in most modern biochemistry
and biophysical chemistry text books.1-10
The nucleic acids deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) have
the same universal functions in all cells, to participate in the storage, transmission and
translation of genetic information. DNA serves as the repository of genetic information
and different kinds of RNA help to translate this information for protein synthesis.
Nucleic acids are formed from nucleotides in different arrangements joined together
through phosphodiester bonds.
The polysaccharides in living systems have two major function, some like starch
are storage forms of energy yielding fuels and others like cellulose functions as
extracellular structural elements. Cellulose and starch are homopolysaccharide of D-
glucose residues connected to each other by glycosidic linkages at 1-4 or 1-6 positions.10
The geometry of these glycosidic linkages confers different structural features and
properties to polysaccharide molecules.10
In cellulose the 1-4 bonds are in -
configuration as a result of which D-glucose chains assume an extended conformation
and undergo side by side aggregation into insoluble fibrils. Linear chain of cellulose in

(3)
the fibrils is held together by crosslinks of large number of hydrogen bonds.10
The
nonionic glucose residue in cellulose contain three free hydroxyl groups, which may
mostly involve either in interchain hydrogen bond formation but few hydroxyl groups
may combine with external water molecules as a result of polymer hydration. The
polysaccharide chain is highly hydrophilic since it contain no obvious apolar moieties but
a large number of hydroxyl groups. Different types of functional groups can be
incorporated in the polysaccharide chain by chemical modification.11
These groups may
impart ionic or hydrophobic character to polysaccharide chain. In carboxymethyl
cellulose, one or more hydroxyl groups in polysaccharide chain of cellulose are replaced
by 
 COOCH2 groups. It is highly soluble in water, when the poly-ion assumes random
coiled conformation.
Starch is a mixture of polysaccharides, -amylose and amylopectin both of which
are made of glucose residues. -amylose consists of long, unbranched chain of D-glucose
units connected by (1-4) glycosidic linkages in contrast to cellulose, where the linkage
is (1-4). The glycosidic linkage joining successive glucose residues in amylopectin are
(1-4), but there exist branch points in this polymer thus forming (1-6) linkages
between glucose residues.10
The geometry of (1-4) bonds favor the polysaccharide
chain to assume tightly coiled helix structure10
in which many hydroxyl groups are in
intrachain hydrogen bonding interaction with each other whereas far off groups
remaining in the outer region of the helix may involve in the process of hydration. Starch
on heating treatment with acids and on enzymatic action modifies to a class of
compounds, which are collectively called dextrins.10,11,12
Like starch, dextrins contain 
(1-4) glycocidic linkages with some (1-6) bonds and they are branched polysaccharides.
Dextrin in aqueous medium forms colloidal solutions. Balasubramanian et al14
have
recently shown that due to spatial arrangement of hydroxyl groups and methines
backbone, one side of the polysaccharide chains becomes hydrophilic and other side
becomes hydrophobic.
Adsorption–desorption phenomena are prevalent in biological systems, which are
of immense important in the field of biology. The cell membranes, liposome, ribosome,
proteins, polysaccharides in insoluble forms are examples of biosrufaces. Since these

(4)
surfaces occur in living systems in contact with water containing different solutes and
salts, the phenomena of adsorption occurs in biological systems. Biosrufaces in many
cases form swollen gels due to their interaction with the bulk water phase, so that the
boundary region between bulk water and biosurface becomes physically undetectable.
The biosurfaces are flexible and highly heterogeneous in nature.
Surfactants and Micelles
Surface-active molecule, which characteristically contain a polar and a relatively
large non-polar portion, are known as surfactants. These can be classified as cationic,
anionic and non-ionic depending upon the charge of the head groups. The most
characteristic and thoroughly studied property of surfactant solution is the co-operative
self-association of the solute within a fairly narrow concentration range in dilute solution
to form high-molecular-weight aggregates known as micelles. This topic has been
reviewed by many workers.15-21
Several methods22-31
are now available for the
determination of critical micelle concentration (cmc) that is the concentration of solute at
which micelle formation first occurs. The size and chemical nature of the surfactant
nonpolar side chain have an important bearing on the magnitude of cmc. It has been
known for a long time32
that the logarithm of cmc varies linearly with the number of
carbon atoms in the non polar side chain of a homologous series. The influence of the
number of ionic groups, branching, unsaturation and substitution of various groups on the
cmc has been collected by Shinada.21
The effect of temperature on the cmc is very small,
so that the best obtainable precision for cmc measurement is required to determine
differences for quantitative purposes. Presence of different types of neutral salts alters the
value of cmc of surfactant.33-34
Addition of low–molecular–weight organic additives to
aqueous solution of surfactants is known to alter the cmc of surfactant.34
The most
commonly used additives have been urea and its derivatives, alcohols, dioxane and
sugars. Each of these types of compounds would be expected to alter the bulk dielectric
constant of the medium and influence the state of salvation of both the polar and non-
polar portion of surfactant molecule.
In addition to cmc of a surfactant, the size of the micelle or the number of
monomeric units in the aggregates (known as the aggregation number) is most important

(5)
in describing the physical state of the systems. Light scattering, sedimentation
equilibrium, membrane osmometry, magnetic resonance, gel filtration, dye solubilisation,
potentiometric titration’s and hydrodynamics are the most commonly used methods for
the determination of aggregation number.35-42
The aggregation number is highly
dependent upon the temperature, nature of head groups and tail part of surfactant
molecules, nature of counterion and presence of organic additives.
Binding of Ligand to Biopolymers
Biopolymers like proteins are formed by polymerization of monomer units within
the living systems forming linear or branched chains, Biopolymer may possess non-ionic
and charged (cationic and anionic) groups. Due to the presence of these side chain
groups, they can interact with neutral and charged ligands as well as metal ions as a result
of binding interaction.
The binding of a ligand L to biopolymers P can be written as
nPLnLP  (1.1)
Here, n stands for number of independent, indistinguishable and identical binding sites.
From the thermodynamic consideration, Scatchard43
has derived equation (1.2) for
binding interaction of ligand with a biopolymer
KC
nKC
a


1
(1.2)
where, a is the number of moles of ligand bound per mole of biopolymer at equilibrium
concentration C of free ligand and K stands for the equilibrium constant for ligand-
biopolymer binding interaction. From the slopes of linear plots of
C
a
against a , values
of n and K can be determined and standard free energy change G (equal to –RT1nK)
for the binding interaction can be obtained. Scatchard equation is not strictly valid if there
is
a) gross conformational change of biopolymer,
b) steric interference of the bound ligand,
c) electrostatic interaction between ionic groups of biopolymer and ligands and

(6)
d) association and precipitation of biopolymers during binding interaction.
Binding interactions between biopolymers and solute occur in biological
systems and such type of interactions play important role in controlling different
biological functions. The case of competitive binding of ligand to proteins has been
treated by Tanford.44
Co-operative binding is often treated as a ligand induced
conformational change and several models45, 46
for such binding interactions are now
available. By appropriate plotting and computer fitting of the experimental data to
different models, one can estimate the degree of co-operativity and site heterogeneity
for protein-ligand systems under study.47-51
The binding constants and
thermodynamic parameters for interactions of proteins with metal ions have been
evaluated by many workers.52-61
The extents of binding of surfactants with proteins have been reported by many
workers.62-65
Chattoraj and co-workers66-72
have studied the binding interactions
between surfactants and proteins or nucleic acid from thermodynamic standpoint
using equilibrium dialysis technique. They have shown that the binding interactions
are controlled by entropy controlled hydrophobic effects and enthalpy controlled
effect.
The interaction between dissolved surfactants and polymers or colloidal particles
is of interest in the areas as diverse as polymer solubilisation,73,74
conformational
changes in biopolymers75-77
and mineral floatation and flocculation including coal
flotation78,79
and clay flocculation.80-82
In the specific case of the binding of ionic
surfactants by dissolved polymers, binding isotherms exhibit a marked degree of co-
operativity.83-86
The interaction between polyions and cationic surfactants in the
presence of different metal ions has been studied by Kwak and co-workers87-89
using
surfactant ion-selective electrode. They have shown that presence of different
multivalent cations interfare with the binding interactions. Using photophysical
techniques90,91
and NMR measurements,92-93
many workers have made attempts to
unravel the structure of the resulting surfactant-polyelectrolyte complex.
Polyelectrolyte-surfactant interactions have been reviewed by Goddard94
and more
recently by Hayakawa and Kwak95
and others.96,97
The general picture for the
interaction in dilute solution is that the surfactant forms micelle like aggregates, binds

(7)
to the polyelectrolyte chains in close analogy with aqueous systems of an uncharged
water soluble polymer and ionic surfactants. The effect of surfactant chain length and
polyelectrolyte molecular weight on the phase behavior of cationic surfactant and
anionic polyelectrolyte has been studied by Karlström et al.98
The aggregation of
alkyltrimethyl ammonium bromide (CnTAB) surfactants in very dilute aqueous
solution of polyelectrolytes have been investigated by Almgren and co-workers.99-101
The interaction of surfactants with non-ionic cellulose ether has been studied very
recently by many workers.98,102-108
Burgaud et al102
have studied interaction of sodium
dodecyl sulphate and hexadecyltrimethyl ammonium bromide and chloride with ethyl
(hydroxyethyl) cellulose using electrical conductivity, self diffusion and fluorescence
quenching. The binding interaction of non-ionic polymers with non-ionic surfactants
has been studied by many workers103-108
owing to their importance in industrial
applications and in biology. The diffusion of non-ionic micelles in solutions and gels
of an ionic polysaccharide have been studied both theoretically and experimentally by
Johansson et al 109
very recently.
Interactions between hydrophobically modified water soluble polymers and
surfactants have gained considerable interest110-124
during last decade. Essentially
these polymers consist of a long chain hydrophilic backbone to which small amounts
of hydrophobic substituents are incorporated through chemical grafting. These
polymers in aqueous solutions undergoes intermolecular association by hydrophobic
association of neighboring groups and this gives rise to the formation of reversible
three dimensional network structure.125,126
Lindman and co-workers127
have recently
studied the rheological and dynamic properties of hydrophobically associated water
soluble polymer in presence of sodium dodecyl sulphate.
Adsorption of Surfactants at Solid-liquid Interfaces
Adsorption of cationic and anionic surfactants at different solid-liquid interfaces
have been studied extensively as functions of the surfactant concentration, pH, ionic
strength and temperature below and above the critical micelle concentration. The
adsorption of surfactants is very useful in the field of detergency and tertiary oil
recovery processes. The phenomena of detergency are described elsewhere.128,129
A

(8)
detailed treatments of adsorption phenomena will be found in the monograph on
colloidal surfactants. In many adsorption isotherms, the experimentally observed
curve deviates from the Langmuir equation due to the strong solute-surface
interaction, between adsorbate and many other factors. These are summarized by
Giles.129a
The critical micelle concentration (cmc) is very important; a break in the
adsorption isotherm often occurs at or near this point. Thus, in the adsorption of
several sodium alkyl sulphates, quaternary ammonium compounds and of two non-
ionic compounds by carbon black, adsorption reached a limiting value close to the
cmc.130
By contrast, the adsorption was found to pass through a maximum and then
decreases, when sodium dodecylsulphate and potassium myristate are adsorbed on
graphite.131
This effect was found to be more pronounced when sodium dodecyl
benzene sulphonate adsorbed onto cotton from 0.01N HCl.132
Eyring et al132
have
proposed that with the increase of surfactant concentration, the size of the micelle
increases as a result of which the micelles are desorbed from the surface.
Tamamushi and Tamaki133,134
have found that the adsorption of cationic and
anionic surfactants by polar solids reaches a maximum value at the cmc of surfactant.
The isotherms have been found to be S-shaped at low concentrations. This
corresponds to electrostatic adsorption of monolayer followed by adsorption of
second layer by van der Waals forces. It has also been proposed that a phase change
occurs, the long-chain ions originally being arranged horizontally with the major axis
parallel to the surface, but subsequently perpendicular to it. The molecular area
occupied by sodium dodecylsulphonate was found to be 65Å2
for adsorption on
Graphon surface.135
Recently Chattoraj et al136
have studied the adsorption of cationic
surfactants at different solid-liquid interfaces and they have found that the molecular
area of adsorbed molecule is highly dependent on the nature of solid surfaces.
Schulman137
has given convincing evidence for the formation of double layers on
barium sulphate for adsorption of sodium dodeyl sulphate at relatively high
concentration. The extent of adsorption depends on surface polarity too.138
Many experimental methods are now available for the study of adsorption of
surfactants at solid-liquid interfaces. Somasundaran et al139,140
have used the method

(9)
of adsorption, emission, magnetic resonance, fluorescence, ESR, excited state
resonance Raman spectroscopy along with adsorption, floatation, flocculation and
electrokinetic’s methods to gather information about the microscopic properties of the
adsorbed surfactant and polymer films. From these studies they have confirmed the
formation of two dimensional aggregates or hemi micelles of long chain ions at the
interface. The technique of specular reflection has been used by Rennie and Co-
workers141
for the study of structure of adsorbed cationic surfactant (CTAB) at silica-
water interface. They have indicated that below cmc, the surfactant molecules
adsorbed as defective bilayer or flattened micelles. Arnebrandt et al142
have reported
that the adsorption of cetyltrimethyl ammonium halide on chromium surface depends
on the ratio of hydrophobic to hydrophilic characters of the solid-liquid interfaces.
Calorimetric studies143,144
of the adsorption of different types of surfactants onto
solid-liquid interfaces have been investigated recently. Using ellipsometric and other
techniques, Lindman and co-workers145
have indicated the formation of micelles at
the solid-liquid interfaces, which may be similar in nature as that formed in the bulk
medium. Adsorption of cationic and anionic surfactants at cellulose-water interface
has been studied by many workers146,147
in relation to detergency. From the
adsorption of chemically related solutes onto cellulose and Chitin, Giles and
Arshid148,149
have reported that cellulose may behave as hydrophobic surface.
Water-Biopolymer Interactions and Excess Hydration
Interaction of biopolymers with water frequently occurs in biological systems
and such types of interaction are of immense importance in controlling different
biological functions. Proteins and nucleic acids characteristically contain different
charged centers and they have the capability to bind water as well as solute molecules
in excess. The polysaccharides contain different functional groups which can interact
with water molecules. The uptake of water by biopolymers in presence of salt is
known as excess hydration.
A wide variety of experimental techniques are now available for the study of
water-biopolymer interactions. These are (i) Thermodynamic (Calorimetry), (ii)
Kinetic (i.e. hydrodynamic measurement of rotational diffusion constants, high

(10)
frequency dispersion techniques), (iii) Spectroscopy (e.g. Infrared, Raman and
Magnetic Resonance Spectroscopy) and (iv) Diffraction (e.g. small angle X-ray
scattering, high resolution studies and X-ray studies).
Interaction of water with proteins has been investigated by several workers150-156
in the presence and absence of neutral salts using different physicochemical
techniques. Following densitometry, Bull157
has given thermodynamic parameters for
bovine serum albumin-water interactions. Privalov and Mrevlishvili158
have studied
calorimetrically the interaction of water with several proteins in their native and
denatured states. Kaivarainen et al159
have studied the hydration of human serum
albumin in solutions of different viscosity in the temperature range 10–40C to
determine the nature of changes in the protein hydration at thermo induced structural
transitions. Using rotational diffusion technique, Edsall160
, Tanford161
, Benoit et al162
and Squire have studied hydration of protein. Infrared spectroscopy has been used by
several workers163-165
for the study of solutions and films of proteins for unraveling
the secondary structure of proteins. Kuntz and co-workers166-169
have performed an
interesting investigation of the hydration of a variety of proteins and their constituent
amino acids. The hydration of DNA has been studied by many workers.170-173
Chattoraj and co-workers150-156, 170
have studied the binding interaction of proteins
and nucleic acids using isopiestic vapor pressure technique from thermodynamic
stand points.
The water-polysaccharide interactions have been studied by several workers174-180
using different physico-chemical techniques. Recently Banerjee et al181
have studied
the thermodynamics of hydration of cellulose and starch in the absence and presence
of neutral salts. They have found that the extent of hydration depends both upon the
nature of neutral salts and on the nature of polysaccharide. The macromolecular
hydration is thoroughly reviewed by Tanford161
and others.182-185
Adsorption at Liquid-Vapor and Liquid-Liquid Interfaces
Adsorption of surfactant at liquid-vapor and liquid-liquid interfaces are in
principle the simplest, because the interface is mobile and the adsorbed phase should
be uniformly distributed in surface phase, so that interfaces attain equilibrium shape

(11)
quickly. But the boundary region between solid and liquid interface is highly
heterogeneous and rigid in structure, so that attainment of equilibrium at solid-liquid
interface takes longer times. Equilibrium at such interface is finally attained within
few hours or few days, so that application of thermodynamic principles appears to be
justified.
The Langmuir theory for the gas adsorption can be applied for the study of
solute adsorption from bulk solution. For the adsorption of solute from solution to the
liquid interface, Langmuir186, 187
has given the equation
2
2
1
2
2
1 KX
KX


 (1.3)
Where, 2 is the extent of adsorption of solute at a given bulk concentration X2 in
mole fraction scale. 1
2 is the maximum extent of adsorption of solute at the state of
monolayer saturation. K stands for the equilibrium constant for the solute-surface
interaction in the monolayer phase.
When the bulk concentration of the solute (X2) is very low, according to the
Langmuir equation, 2 versus X2 plot will be linear, but for higher values of X2 it
reaches a limiting value 1
2 . Gibbs adsorption equation188
(1.4) can be used for the
calculation of surface excess ( 1
2 ) of the component 2 adsorbed from binary solution
to the liquid-vapor and liquid-liquid interfaces.
2
21
2
da
d
RT
a 
 (1.4)
Here  is the boundary tension of the solution, which can be calculated from the
experiment, a2 is the activity of the component 2 in the liquid phase. For dilute
solution a2 can be taken as equal to the concentration C2. The measurement of  at
different values of a2 can be used for the calculation of 1
2 at different values of a2. If
2da
d
becomes negative that is interfacial tension decreases with a2, the component 2
is accumulated at the interface as positive excess and when
2da
d
is positive that is the
interfacial tension increases with a2, the component 2 is accumulated at the interface

(12)
as negative excess.
Many imaginary models for the interfacial region have been put forward by
several workers189-199
in deriving theoretical equations relating , a2 and 1
2 . Gibbs188,
200
regarded the surface phase as an idealized model possessing zero thickness. This
may be achieved by the arbitrary placement of phase-dividing mathematical plane at a
specific position near the actual interface such that relative accumulation of solvent
component 1 at the interface becomes zero.
For a multicomponent liquid system containing i components, in contact with
gas, the Gibbs equation reads
i
x
i
xx
dddd   2211 (1.5)
Here 1, 2 ………. i are chemical potentials of the components in the bulk phase
and x
i
xx
 21 , are values of surface excess of these components per unit area
when the dividing plane is placed at a fixed position x very near the surface. If the
dividing plane is placed at a particular position of x when the surface excess of
component 1 ( x
i ) becomes zero then
ii dddd  1
3
1
32
1
2   (1.6)
Here 11
3
1
2 , i  are relative surface excesses of solute with respect to the
solvent component 1. It has been shown from the theoretical analysis that the values
of 1
2 , 1
2 and 1
i are not dependent on the arbitrary position of the dividing plane.
For dilute binary solution of non-electrolyte, replacing d2 = RTdlna2, equation (1.6)
can be converted to equation (1.4).
If the dividing plane is placed at a position such that the surface excess of
component 2 becomes zero then
- ii dddd  2
3
2
31
2
1   (1.7)
Here 2
1 , 2
3 , …….. 2
i are relative surface excesses of component 1, 3, 4 …… i with
respect to the solute component 2.
Equilibrium Adsorption of Proteins at Solid-Liquid Interfaces
Adsorption of proteins onto solid-liquid interface is important in

(13)
biotechnological and biomedical fields.201,202
To understand the complex features of
the interaction of proteins with heterogeneous interfaces, the adsorption of proteins at
model solid surfaces has been studied extensively203-208
at varying pH, ionic strength
and temperature. From these studies the surface concentration of proteins on various
materials, orientation of the protein molecules on the solid surface at the state of
monolayer saturation, shapes of various adsorption isotherms and various
thermodynamic parameters for protein adsorption have been evaluated. The rich
source of information on protein adsorption upon solid surfaces is chromatographic
studies209-212
and biomaterials.203-215
The chromatographic studies have established
the importance of electrostatic, hydrophobic and charge transfer interactions of
proteins with solid support.
Andrade216
has reviewed the various features of protein adsorption at solid-liquid
interfaces in details. Norde217
has examined the adsorption of globular proteins in
terms of roles played by various properties of proteins, sorbent and medium. Greig
Russel at al218
has discussed in detail the protein adsorption with special attention to
the importance of ascertaining the presence of polymeric species on adsorption
studies of proteins. In relation to bio and blood compatibility and fouling,
Lundsfroem219
have reviewed the protein adsorption on metal and metal oxides.
Sevastianov220
has examined the role of protein adsorption in blood compatibility of
polymers. Norde et al221
have examined the protein adsorption and bacterial adhesion
based on a colloidal chemical approach. The role of hydrophobic, electrostatic and
van der Waal’s forces in these processes have been discussed.
Bull222
has studied the adsorption of BSA on Pyrex glass as function of pH and
ionic strength of the medium. A definite effect of hydrophobicity of interface on the
electrophoretic mobility of protein coated particles has been studied by Chattoraj and
Bull223
. MacRcitchie has observed that maximum amount of protein adsorbed on
hydrophobic surfaces is higher than that of hydrophilic silica under identical
conditions. Mitra and Chattoraj224
have studied adsorption of BSA on positively
charged alumina surface at both low and high concentration of proteins. Sarkar and
Chattoraj225,226
have studied the excess adsorption of lysozyme at different solid-
liquid interfaces under varied physico-chemical conditions. They have also studied

(14)
the effect of denaturants and stabilizer on protein adsorption at different solid-liquid
interfaces. Dillman and Miller227
have investigated the adsorption of proteins on a
series of polymer membranes and they have distinguished two independent types of
adsorption on these membranes. Fair et al228
have reported the bi-model
characteristics of adsorption isotherms of BSA and -globulin at polystyrene latex
surfaces. Norde and co-workers229,230
have studied adsorption of human plasma
albumin (HPA) and dextran on silver iodide-water interface and they have concluded
that the adsorption is competitive in nature and the process is entropy controlled.
Norde and Lyklema203-208
have observed that the adsorption of HPA and bovine
pancreas ribonuclease on negatively changed polystyrene latex have reached a plateau
levels at higher protein concentration. The effect of neutral salts, urea and glutamic
acid on the adsorption of various proteins on silicone coated glass surface has been
studied by Mizutani. Hazra and Chattoraj231-234
have studied adsorption of different
proteins at different solid-liquid interfaces in pure or mixed forms.
The adsorption of proteins at solid-liquid interfaces has been studied using
different instrumental techniques such as radiotracer,235
tunneling microscopy,236
ellipsometry,237
total internal reflection fluorescence spectroscopy.238-241
Desorption Phenomena
Protein molecules are adsorbed at solid surfaces by the attachment of different
functional segments in a specified conformation and the adsorption process is
irreversible. Desorption of adsorbed protein by dilution is very difficult,242,243
However, cleaning of the surface has been achieved by change of pH, ionic strength
of the solvent as well as by alkaline or detergent solutions. Another important finding
is that adsorbed proteins can exchange with the proteins dissolved in the solvent.244,245
The difference between desorption and exchange have been explained by
Jennisen.246-250
The protein molecule adsorbed at the surface with multiple binding
sites called foot and statistically a binding site may lift off from the surface now and
then. For complete desorption all the binding sites must be lifted off from the surface.
This is statistically improbable and thus desorption can not occur. Exchange is a
different phenomenon. Here the proteins present in the local environment, diffusing

(15)
to and colliding with surface. If one of the proteins statistically places a foot on the
space vacated by a desorbing foot of an adsorbed protein, then a competition
develops. Under these circumstances, one molecule of one protein can in essence be
lifted off by a number of protein molecules adsorbing and attempting to accommodate
with the surface.
Recently Lundström and Elwing245
have proposed a simple kinetic model for
protein exchange reactions on solid surface. They have discussed some microscopic
details related to spontaneous desorption and exchange reactions and made some
general conclusions about different surfaces. The results obtained from the model
calculations are in qualitative agreement with experimental results. They particularly
emphasize the importance of slow dynamic phenomena taking place after initial
adsorption of protein molecules. Norde and Favier251
have made a comparative study
of the structure of adsorbed and desorbed proteins.
The surfactant mediated elution of adsorbed proteins from solid surfaces has been
undertaken by many workers recently.252-260
These studies may provide information
regarding the index of protein binding strength. The incomplete removal of adsorbed
protein has been attributed to the presence of multiple states of adsorbed protein i.e.
some of the protein is apparently bound through a number of noncovalent contacts
sufficient to render it nonremovable under the selected experimental conditions.
These studies have also shown that in addition to its binding strength, the elutability
of an adsorbed protein is influenced by the type of eluant and surface used as well.
Recently McGuire and co-workers261-263
have studied the elution of proteins from
salinized silica surfaces. The kinetics of desorption of different proteins from alumina
surface has been studied by Sarkar et al.264
They have found that desorption of
proteins follow a multistep kinetic rate equation.
Thermodynamics of Adsorption at Different interfaces
The thermodynamic treatment of adsorption from solution involves a satisfactory
treatment of the solution itself as well as of the interfacial phenomena. Attempt has
been made for the calculation of standard free energy of adsorption at different types
of interfaces. The Langmuir adsorption equation (1.3) is used for the calculation of

(16)
standard free energy change (G) for monolayer adsorption from the value of
equilibrium constant K (equal to RT
G
e
0


). Traube265
observed regularity in the lowering
of the surface tension of water by members of the three homologous series of fatty
acids, alcohols and esters at low concentrations. This can be generalized as follows, in
a homologous series of surface-active substances there is a constant ratio between the
molar concentrations of two successive homologues giving rise to the same very
lowering of surface tension in aqueous solutions. This law is usually known as
Traube’s rule.266
The physical significance of Traube’s rule has been given by
Langmuir267
and he from theoretical consideration has shown that the standard free
energy per –CH2- group for such adsorption is -625cal/mole at 25C at the air-water
interface. The quantitative application is shown in Haydon and Taylor’s268
data for
adsorption of the fatty alcohols from aqueous solutions at the petroleum–ether
interface. The magnitude of free energy of adsorption increases linearly with
increasing chain-length, corresponding to an increase of -820cal per mole for each -
CH2- group. This value of 0
2CHG depends on the change of environment of the
interface. The value of 0
2CHG is only 50-100cal/mole for adsorption of long-chain
alcohols at the octane-water interface. These aspects of Traube’s rule have also been
considered by Vignes.269
The Langmuir equation, with some modifications for adsorption at liquid interfaces
may be written as270





 

 RT
GC
AA
A
AA
A R
0
0
0
0
0
exp
5.55
exp (1.16)
Where CR is the concentration of solute in bulk, A is area occupied per molecule at
the interface; Ao is the physically excluded area at the interface per molecule.
Equation (1.16) has been used for the calculation of standard free energy (G) for
adsorption of monobasic and dibasic acids at oil-water interfaces.271-273
The approach
for the calculation of G in this manner has been modified to take into account ionic
nature of adsorbed molecule. The free energy of adsorption at liquid interface has
been calculated on the basis of Szyszkowsk,274
equation. Ronsen and Aronson275
have
proposed a thermodynamic equation for calculation of free energy of adsorption.

(17)
Many workers have calculated the standard free energy change (G) for
adsorption of solute from binary solution at solid-liquid interfaces using equation
(1.17)276, 277
2
1
2
ln
C
RTG


 (1.17)
Where C2 is the solute concentration in the bulk,  is the thickness of the interfacial
phase. Bull and Breese278
have calculated values of G for a series of amino acids
adsorbed at air-water interface. Equation (1.18) has been used by many workers279-281
for the calculation of standard free energy change for monolayer adsorption at air-
liquid interfaces
bRTG  0
(1.18)
Where b is a constant and equals to
2dC
d
.  is the boundary tension measured at
extremely dilute solution.
Bull282, 283
has deduced an explicit expression (1.19) for the free energy change of
adsorption using the concept of the Gibbs adsorption equation
2
2
0
1
22
1
2
2
ln
C
dC
RTCRTG
C
B  (1.19)
Her GB stands for standard free energy change for the transfer of 1
2 moles of solute
from solution in the bulk to the solid-liquid interface, when bulk concentration C2 is
altered from zero to unity. From the slope of the linear plot of GB and 1
2 , Bull has
calculated the standard free energy change 0
BG . Chattoraj and co-workers have used
the above equation for calculation of 0
BG due to adsorption of different proteins,
surfactants at oil-water interface284
and different solid-liquid interfaces285-287
using
mole fraction scale rather than molar scale for solution activity.
After necessary correction of the reference state in Bull’s equation (1.19),
Chattoraj et al286,287,66,67
have calculated the free energy change (G) from the
following equation
2
1
22
0 2
1
2
ln
2
XRTdX
X
RTG
X


  (1.20)

(18)
The standard free energy change (G) have been calculated using equation
(1.21)97,287, 288
m
GG
2
1
20


 (1.21)
where m
2 is the maximum extent of adsorption at the interface. The value of G can
be obtained from the slope of the linear plot of G vs. m
2
1
2


for various systems and
can be compared with each other under identical state of reference.
Further equation (1.21) can be written as
0
1
2
0
2
0
B
ap
m
G
GG






(1.22)
Where 0
BG is the standard free energy change for transfer of one mole of solute from
the bulk to the interface when bulk activity of solute is varied from zero to unity.
The standard enthalpy change (H) for the transfer of one mole of a solute to
the interface can be calculated from the Gibbs free energy using the following
thermodynamic relation
0
0
1
H
T
d
T
G
d












 
(1.23)
Kinetics of Adsorption from Liquid Phase
Like adsorption from gaseous phase, adsorption from liquid phase at the interface
takes place in different kinetic steps until the state of equilibrium is attained. The time
required for attainment of equilibrium depends on the nature of interface, the nature
of solvent and on the presence of different additives in the liquid phase. The
molecular weight and also the concentration of adsorbate influence the rate of
adsorption, which may reflect the possibility of diffusion of adsorbate at the
interfacial region.

(19)
Kinetics of Adsorption at Liquid-Vapor and Liquid-Liquid Interfaces
Surfactants and proteins are surface-active agents. Due to excess accumulation of
these substances from solution phase to interfacial phase, the surface tension is
lowered considerably. Thus variation of surface tension with time gives a convenient
method for following the kinetics of adsorption at these two interfaces. The transfer
of surface-active substances from the bulk solution to the smooth gas-liquid and
liquid-liquid interfaces under various solution parameters (like pH, temperature and
ionic strength) have been carried out by several workers289-292
from the rate of
decrease of boundary tension () with time, when bulk solution is not stirred. Under
this unstirred condition, Phillips et al293
have measured the rate of adsorption of
labeled protein to the fluid surface by radio tracer technique and they have calculated
the diffusion co-efficient of protein using classical Ward and Tordai equation294
which reads

Dt
C0
2
1
2 2

D
2   2
1
0
2  dtC
t
S
 (1.24)
Here 1
2 stands for extent of adsorption in moles per square centimeter, 0
2C and s
C2
are the bulk and subsurface concentration of the protein in cm3
, D is the diffusion co-
efficient in cm2
/sec. as defined by Fick’s equation. Also, t stands for time in seconds
and  is the dummy time variable. The second part in the right hand side of equation
(1.24) arises due to the desorption of solutes from the surface.
At early stages of adsorption, desorption from the interface has been neglected
when the rate of arrival of molecules at an interface is diffusion controlled and
activation energy is zero. Neglecting at this stage the second term on the right hand
side of equation (1.24), 1
2 can be related to D by the following equation

Dt
Cp
01
2 2 (1.25)
Alexander and co-workers295-298
have outlined the likely stages of adsorption of
proteins at liquid-vapor and liquid interfaces. These are (1) diffusion of protein to the
interface, (2) penetration and anchorage of protein to the surface, (3) conformational
change of the biopolymer at the interface. Due to the presence of both nonpolar and

(20)
polar groups in its side chain, a protein molecule on reaching the interface can
penetrate the interfacial region which results in the increase of surface pressure.
Thus changes in  provide a convenient way of monitoring penetration of biopolymer
molecule onto the surface as well as the configurational rearrangement of protein
molecules in the adsorbed state. The rates of these processes can be analyzed by the
first order equation299
having rate constant k.


 t
ss
tss








0
ln 
Where, ss, 0, and t are values of surface pressure at steady state, at t equal to zero
and at any time t respectively.  is the relaxation time (equal to k-1
).
The rate of change of  with time can also be analyzed by the following equation
given by Ward and Tordai294
and modified by Mac Ritchie and Alaxander297
kT
A
Ck
dt
d
b






 
)log(log 1 (1.27)
here, k1 is the kinetic rate constant and Cb is also a constant. Also k and T are
Boltzman constant and absolute temperature respectively A is the work done in
creating space of area A in a film of surface pressure . A represents the surface
area swept out by the protein residues during their adsorption at the interface.
Ghosh and Bull300
have used the pendant drop method for measuring interfacial
tension of proteins. Das and Chattoraj301
have studied the interfacial tension between
polar oil and a protein solution as a function of time by Wilhelmy plate method and
found that globular BSA is more sensitive than denatured gelatin in lowering
interfacial tension at a fixed pH and ionic strength. The kinetics of adsorption of
proteins at liquid-vapor and liquid-liquid interfaces has been studied by many
workers302-312
with many interesting results.
The dynamic and mechanistic aspects of adsorption of surfactants at liquid-vapor
and liquid-liquid interfaces have been investigated by several workers313-324
using
different techniques such as Oscillating jet method, inclined plane method, the
dynamic capillary method, the free falling film method, drop-volume method and the
maximum bubble pressure method. The general picture for the adsorption process is

(21)
that the surfactant molecules are transported from the bulk to the subsurface by
diffusion and then transfer occurs from the subsurface to the actual surface. The
second order harmonic generation has been used by Rasing et al325
for the study of
kinetics of adsorption of surfactants at liquid-air interface. They have found two
different regimes in the dynamic process, the initial fast adsorption due to diffusion
followed by a slow adsorption regime. The equilibrium and dynamic aspects of
surfactant adsorption at fluid interfaces can be obtained from the recent reviews made
by Miller et al326
. Borwarkar et al327
have proposed a model for equilibrium and
dynamics of adsorption at fluid-fluid interfaces
Kinetics of Adsorption at Solid-Liquid Interfaces
Unlike liquid-vapor and liquid-liquid interfaces, the kinetics of adsorption at
solid-liquid interfaces cannot be monitored by measuring the change of surface
pressure with time. The analysis of dynamic aspects of adsorption at solid-liquid
interfaces is relatively a new development. The amount of protein adsorbed at solid-
liquid interfaces as function of time at fixed temperature can be studied by solution
depletion technique, reflection fluorescence spectroscopy, reflection IR spectroscopy,
reflection Raman spectroscopy, ellipsometry and radiotracer techniques. All of these
techniques are developed within twenty years.
For the study of adsorption kinetics at solid-liquid systems, the solution has to be
stirred to keep the solid particles in the suspended state, so that its maximum surface
area has been fully exposed for adsorption to take place. Whereas, the study of
adsorption at liquid-vapor and liquid-liquid interfaces no such stirring is necessary.
Thus in the case of solid-liquid systems, the Ward and Tordai295
equation cannot be
applied.
Following an alternative approach, Bull328
has derived an equation for the
calculation of the diffusion co-efficient of proteins at solid-liquid interface, when the
bulk solution is in contact with the suspended solid particles is stirred. According to
the Fick’s law
X
CD
t
C pp





(1.28)

(22)
Here X is the distance from the surface and Cp is the protein concentration.
When during adsorption study, the solution in contact with the solid surface is
stirred, the gradient in the bulk solution vanishes and protein concentration becomes
uniform throughout the bulk. In this case however, this layer of bulk solvent adhered
to the surface of the solid remains fixed and unaffected by bulk stirring process.
The solute dissolved in adhered solvent attached to the plane solid surface
may vary in gradient manner from bulk concentration Cp at X = X1
to its maximum
concentration 0
pC at X = 0. Assuming the gradient to be linear, -
dX
dC p
will be equal
to

0
pC
 (The negative sign implies that Cp increases as X decreases) Equation (1.28)
now assumes the form

0
0
p
x
p DC
dt
dC







(1.29)
Since

p
x
p
dt
dC 






0
we can write

tDC p
p
0
 (1.30)
Which on integration between the limit t = 0 to t, gives the final mass transfer
equation for stirred solution

tDC p
p
0
 (1.31)
Kinetics of Adsorption of Surfactants at Solid-Liquid Interfaces
The kinetics of adsorption of non-ionic surfactants onto hydrophilic solids has
been studied by Klimenko et al329
and Partyka et al.330
Klimenko and co-workers329
have concluded that adsorption involves a surface aggregative process that is similar

(23)
to bulk micellisation. They further found that the rate of adsorption to be directly
correlated to the monomer surfactant concentration in water, leading to the common
opinion that micellar transport is not involved in the adsorption process.
Ghosh et al331
have studied the kinetics of adsorption of ionic surfactants at
alumina-water interface. They have found that the adsorption process is diffusion
controlled and the diffusion co-efficient calculated from kinetic data are dependent
upon the chain length of surfactant molecule.
Very recently Tiberg et al332,333
have investigated the adsorption and desorption
kinetics of non-ionic surfactants at hydrophilic silica surface using in situ
ellipsometry. They have proposed a kinetic model based on their experimental data.
They have also found that the adsorption process is diffusion controlled and the
thickness of adsorbed layer remains fixed during the major part of adsorption-
desorption process.
Scope of the Present Work
From all these discussion, it is evident that extensive work has been done on the
interaction of surfactants with proteins and nucleic acids. Compared to this, the
interest on the study of interaction of surfactants with polysaccharides and their
derivatives has been shown by several workers only in recent years. These studies are
regarded to be useful in understanding different phenomena occurring in biological
systems. In the present study we have chosen three different polysaccharides
cellulose, dextrin and carboxymethyl cellulose for the study of their interaction with
different cationic surfactants. The role of hydration, hydrophobic and electrostatic
interaction in the binding process may be of considerable interest and this will be
dealt with in detail in the present investigation. Earlier discussion in the introduction
in Chapter 1 has indicated that the equilibrium aspects of adsorption of surfactant at
liquid-vapor, liquid-liquid and solid-liquid have already been investigated most
extensively by many workers. Elaborate research work have also been done
simultaneously for a few decades on the kinetics of adsorption of surfactants at
liquid-air and liquid-liquid interfaces. But in contrast to this investigation on the
kinetics of adsorption of surfactants at solid-liquid interfaces are undertaken by only

(24)
by a few workers quite recently. For these reasons, the study will be undertaken in the
present thesis on the kinetics of adsorption of cationic surfactants at silica-water and
charcoal-water interfaces under various physico-chemical conditions. Attempt will be
made to evaluate the different rate constants associated with such kinetic processes.
Based on these experimental results, probable mechanism for such adsorption process
will also be proposed.
We also note from the discussion given earlier that adsorption of proteins at
different solid-liquid interfaces has been the subject of extensive study for the last
few decades but investigation on the desorption phenomena of proteins from solid
surfaces is relatively new. In the present work, the kinetics of desorption of proteins
from hydrophilic silica and hydrophobic charcoal in the presence of different
desorbing agents will be studied at different physico-chemical conditions. Attempt
will be made for the evaluation of kinetic rate constants associated with the
desorption process. The values of different activation parameters will evaluated and a
probable mechanism for the desorption of adsorbed protein will be proposed.

(25)
References
1. Stryer, L.; Biochemistry, 2nd
Ed., W. H. Freeman Co., San Francisco, 1981.
2. Dickerson, R. E.; Geis, I., Structure and Action of Proteins, Harper and Row,
New York, 1969.
3. Schulz, G. E.; Schirmer, R. H., Principles of Protein Structure, Springer-Veriag,
New York, 1979.
4. Friefelder, D., Physical Biochemistry, 2nd
Ed., W. H. Freeman Co., San Francisco,
1982.
5. Cantor, C. R.; Schimmel, P. R., Biophysical Chemistry, W.H. Freeman Co., San
Francisco, 1980.
6. Dickerson, R. E; Geis, I., Hemoglobin, Benjamin/Cummings, Menlopark, CA,
1983.
7. Walton, A. G.; Blackwell, J., Biopolymers, Academic Press, New York, 1973.
8. Walton, A. G., Polypeptide and Protein Structure, Elservier, New York, 1981.
9. Tanford, C., Physical Chemistry of Macromolecules, Wiley, New York, 1961.
10. Lehninger, I. L., Principles of Biochemistry, CBS Publications, (Indian Edition).
11. Dey, P. M.; Prinson, K., In “Advances in Carbohydrate Chemistry and
Biochemistry, Tipson, R. S.; Hortor, D., Eds., Academic Press Inc., New York,
London, 1984, Vol. 42, PP. 294.
12. Safterthwaite, R. W.; Iwinski, D. W., In “Industrial Gums,” Whistler, R. L.;
Bensiller, J. N., Eds; 2nd
Edition, 1973.
13. Dexter, F. In Advances in Carbohydrate Chemistry, Wolfform, M.L. and Tipson,
R. M., Eds., 1965, Vol. 12, pp. 189.
14. Balasubramanian, D.; Raman, B.; Sundari, C. J. Am. Chem Soc., 1993, 115, 74.
15. Bhaskar, S. M., In “Adhesion in Biological System,” (R. S. Mandy, Cd),
Academic Press, New York and London, Chapter 12, 1970.
16. Corkill, J. M.; Goodman, J. F., Adv. Colloid Interface Sci., 1969, 2, 297.
17. Ivin, K. J., In “Polymer Handbood,” (J. Brandrup and E.H. Immergut, eds.)
Wiley-Interscience, New York, 1966, P. 11.
18. Miller, T. A.; Adams, R. N., J. Amer. Chem. Soc., 1966, 88, 5713.

(26)
19. Muller, N., In “Reaction Kinetics in Micelles,” Amer. Chem. Soc. Symp. (E.
Corles, ed.) Plenum Press, New York, 1953, P.1.
20. Schiek (ed.) “Nonionic surfactants,” Marcel Dekker, New York, 1967.
21. Shinoda, K.; Nakagawa, T. in “Colloidal Surfactants,” (B.I., Tamamushi and T.
Isemura eds.), Academic Press, New York, 1963.
22. Mukherjee, P.; Perrin, J.; Witzke, E., J. Pharm. Sci., 1970, 59, 1513.
23. Peri, J. B., J. Colloid Interface Sci., 1969, 29, 6.
24. Muller, N.; Birkham, R. H., J. Phys. Chem., 1968, 72, 563.
25. Lindman, B.; Danielsson, I., J. Colloid Interface Sci., 1972, 39, 349.
26. Johansson, A.; Eriksson, J. C.; Andersson, L. O., Chem. abstr. 1971, 74, 118097.
27. Rehfeld, S. J., J. Colloid Interface Sci., 1970, 34, 518.
28. Malcolm, G. M.; Rowlinson, J. S., Trans. Faraday Soc., 1957, 53, 921.
29. Williams, E. J.; Smoler, V. F., J. Pharm. Sci., 1972, 61, 639.
30. Schinozuka, N.; Suzuki, H.; Hayano, S., Kolloid-Z. Z-Polym., 1971, 248, 959.
31. Choulis, N. H.; Loh, L. H., Can. J. Pharm. Sci., 1967, 23, 1038.
32. Klevens, H. B., J. Phys. Chem., 1948, 52, 130.
33. Malik, W. U.; Jhamb, O. P., Kolloid-Z, 1970, 242, 1209.
34. Ray, A.; Nemethy, G., J. Amer. Chem. Soc., 1971, 93, 6787.
35. Anacker, E. W.; Rush, R. M.; Johanson, J. S., J. Phys. Chem., 1964, 68, 81.
36. Herrmann, K. W.; Benjamin, l., J. Colloid Interface Sci., 1967, 23, 478.
37. Attwood, D.; Elwarth, P. H.; Kayne, S. B., J. Phys. Chem., 1970, 74, 3529.
38. Muller, N.; Platko, F. E., J. Phys. Chem., 1971, 75, 547.
39. Suzuki, H.; Sasaki, T., Bull. Chem. Soc. Japan, 1971, 44, 2630.
40. Jacobs, P. T.; Geer, R. D.; Anacker, E. W., J. Colloid Interface Sci.,1972, 39, 611.
41. Yalkowsky, S. H.; Zografi, G., J. Colloid Interface Sci., 1970, 34, 525.
42. Courchene, W. L., J. Phys. Chem., 1964, 68, 1870.
43. Scatchard, G.; Ann. N. Y., Academic Sci., U.S.A., 1949, 51, 660.
44. Tanford, C., Physical Chemistry of Macromolecules, Wiley, New York, 1961.
45. Poland, D., Cooperative Equilibria in Physical Biochemistry, Oxford Univ. Press,
Oxford, 1978.
46. Lavitski, A., Quantitative Aspects of Allosteric Mechanisms, Springer – Verlag,

(27)
Berlin, 1978.
47. Steinhardt, J.; Reynolds, J. A., Multiple Equilibria in Protein, Academic Press,
New York, 1969.
48. Van Holde, K. E., Physical Biochemistry, Prentice Hall, Englewood Cliffs, New
Jarsey, 1971.
49. Marshall, A. G., Biophysical Chemistry, Wiley, New York, 1978.
50. Klotz, I. M., Protein Interactions, in: The Proteins, Vol. 1B (H. Neurathand K.
Bailey eds.) Academic press, New York, 1953, P. 729.
51. Scatchard, G.; Coleman, J. S.; Shen, A. L., J. Amer. Chem. Soc., 1957, 79, 12.
52. McMichael, J. C.; Lauffer, M. A., Arch. Biochem. Biophys. 1975, 169, 209.
53. Durham, A. C. H.; Hendry, D. A.; Von Wechmar, M. B., Virology, 1977, 77(2),
524.
54. Sundararanjan, N. R.; Witney, R. Mel., J. Dairy Sci., 1969, 52, 1445.
55. Walterson, J. G.; Kohler, L.; Schaub, M. C., J. Biol. Chem., 1979, 254, 6470.
56. Bagshaw, C. R., J. Muscle Res. Cell Motil. 1980, 1, 255.
57. Eristavi, T. M.; Dzhapasidze, Z. O.; Charkviani, G. G., Biofzika, 1981, 26, 931.
58. Yamada, K.; Kometani, K., J. Biochem., 1982, 92, 1505.
59. Wakameda, A.; Arai, K., Nippan Suisan Gakkaishi, 1983, 49, 643.
60. Wakameda, A.; Arai, K., Nippan Suisan Gakkaishi, 1986, 52, 293.
61. Clarke, S., J. Biol. Chem., 1975, 250, 5459.
62. Steinhardt, J.; Scolt, J. R.; Birdi, K. S., Biochemistry, 1977, 16, 718.
63. Megard, D.; Kitabatake, N.; Cheftel, J. C., J. Food Sci., 1985, 50, 1364.
64. Egelandsdal, B.; Fretheim, K.; Harbitz, O., J. Food Sci., 1985, 50, 1399.
65. Reynolds, J. A.; Tanford, C., J. Biol. Chem., 1970, 24, 5161.
66. Sen, M.; Mitra, S. P.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1980, 17, 370.
67. Sen, M.; Mitra, S. P.; Chattoraj, D. K., Colloids and Surfaces, 1981, 2, 259.
68. Sen, M.; Mitra, S. P.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1980, 17, 405.
69. Sadhukhan, B. K.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1983, 20, 66.
70. Maulik, S.; Jana, P. K.; Moulik, S. P.; Chattoraj, D. K., Biopolymers, 1995, 35,
533.
71. Das, M.; Chattoraj, D. K., Colloids Surfacs. 1991, 61, 1.

(28)
72. Maulik, S.; Maulik, S. P.; Chattoraj, D. K., Bull. Chem. Soc., 1996, 69, 1.
73. Isemura, T.; Imanishi, A., J. Polym. Sci., 1958, 33, 337.
74. Jonnes, M. N., J. Colloid Interface Sci., 1967, 23, 36.
75. Sarkar, D. K.; Doty, P., Porc. Natl. Acad. Sci., U.S.A., 1966, 55, 981.
76. Grourke, M. J.; Gibbs, J. H., Biopolymers, 1967, 5, 586.
77. Satake, I.; Yang, J. T., Biochem. Biophys. Res. Commun., 1973, 54, 930.
78. Basenkova, V. L.; Zubkova, Yu. N., Khim. Tver. Topl. (Moscow), 1977, 11, 137.
79. Przhegorlinskaya, R. V.; Zubkova, Yu. N., Khim. Tver. Topl. (Moscow), 1978,
12, 125.
80. Hanna, H. S.; Somasundaran, P., J. Colloid Interface Sci., 1979, 70, 181.
81. Law, J. P. Jr.; Kunze, G. W., Soil Sci. Am. Proc., 1966, 30, 321.
82. Howler, W. F., Clays. Clay Miner, 1970, 18, 97.
83. Aria, H.; Murata, M.; Shinoda, K., J. Colloid Interface Sci., 1971, 37, 223.
84. Satake, I.; Yang, J. T., Biopolymers, 1976, 15, 2263.
85. Satake, I.; Gonda, T.; Kimizuka, H., Bull. Chem. Soc., Jpn. 1979, 52, 361.
86. Shirahama, K.; Yuasa, H.; Sugimoto, S., Bull. Chem. Soc. Jpn., 1981, 544, 375.
87. Hayakawa, K.; Kwak, J. C. T., J. Phys. Chem., 1982, 86, 3866.
88. Hayakawa, K.; Kwak, J. C. T., J. Phys. Chem., 1983, 87, 506.
89. Santerre, J. P.; Hayakawa, K.; Kwak, J. C. T., Colloids Surfs., 1985, 13, 35.
90. Abuin, E. B.; Scaiano, J. C., J. Amer. Chem. Soc., 1984, 106, 6274.
91. Chu, D.; Thomas, J. K., J. Amer. Chem. Soc., 1986, 108, 6270.
92. Gao, Z.; Wasylishen, R. E.; Kwak, J. C. T., J. Colloid Interface Sci., 1988, 126,
371.
93. Gao, Z.; Wasylishen, R. E.; Kwak, J. C. T., J. Phys. Chem., 1990, 94, 773.
94. Goddard, E. D., Interactions of Surfactants with Polymers and Proteins; Goddard,
E. D.; Ananthapadmanabhan, K. P. Eds.; CRC Press, Boca Raton, 1993.
95. Hayakawa, K.; Kwak, J. C. T., Cationic Surfactants – Physical Chemistry,
Rubingh, D., Holand, P., Eds.; Dekker, New York, 1991.
96. Saito, S., Non-ionic Surfactants – Physical Chemistry; Schiek, M. J., Ed. M.
Dekker, New York, 1989, Chap. 15.
97. Lindman, B.; Thalberg, K., In Interactions of Surfactants with Polymers and

(29)
Proteins; Goddard, E. D., Ananthapadmanabhan, K. P., Eds.; CRC Press, Boca
Raton, 1993.
98. Thalberg, K.; Lindman, B.; Karlström, G., J. Phys. Chem., 1991, 95(8), 3370.
99. Hansson, P.; Almgren, M., J. Phys. Chem., 1995, 99, 16694.
100. Hansson, P.; Almgren, M., Langmuir, 1994, 10, 2115.
101. Hansson, P.; Almgren, M., J. Phys. Chem., 1996, 100, 9038.
102. Kamenka, N.; Burgaud, I,; Zana, R.; Lindman, B., J. Phys. Chem., 1994, 98,
6785.
103. Weckström, K., FEBS Lett. 1985, 192(2), 220.
104. Brackman, J. C.; Van, OS, M. M.; Engberis, B. F. N., Langmuir, 1988, 4, 1266.
105. Wormuth, K. R., Langmuir, 1991, 7, 1622.
106. Zhang, K., Karlström, G,; Lindman, B., Colloids surfaces, 1992, 67, 147.
107. Penders, M. H. G. M.; Nilsson, S.; Picullel, L.; Lindman, B., J. Phys. Chem.,
1993, 97, 11332.
108. Zhang, K.; Jonström, M.; Lindman, B., J. Phys. Chem., 1994, 98, 2459.
109. Johnsson, L.; Hedberg, P.; Löfroth, J.E., J. Phys. Chem., 1993, 97, 747.
110. Carlsson, A.; Karlström, G.; Lindman, B., Langmuir, 1986, 2, 536.
111. Winnik, F. M., Langmuir, 1990, 6, 522.
112. Hu, Y. Z.; Zhao, G. L.; Winnik, M. A.;Sundaranjan, P. R., Langmuir, 1990, 6,
880.
113. Sivadasan, K.; Somasundaran, P., Colloids Surfaces, 1990, 49, 229.
114. Tanaka, R.; Meadows, J.; Phillips, G.O.; Williams, P.A., Carbohydrate Polym.,
1990, 12, 443.
115. Dualeh, A. J.; Steiner, C. A., Macromolecules, 1990, 23, 251.
116. Carlsson, A.; Karlström, G.; Lindman, B., Colloids Surfaces, 1990, 47, 147.
117. Dualeh, A. J.; Steiner, C. A., Macromolecules, 1991, 25, 112.
118. Magny, B.; Iliopoulos, I; Audebert, R.; Picullel, L.; Lindman, B., Prog. Colloid.
Polym. Sci., 1992, 89, 118.
119. Tanaka, R.; Meadows, J.; Williams, P. A.; Phillips, G. O., Macromolecules, 1992,
25, 1304.
120. Kastner, U.; Hoffman, H.; Dönges, R.; Ehrler, R., Colloids Surfaces A, 1994, 82,

(30)
279.
121. Hulden, M., Colloids Surf. A., 1994, 82, 263.
122. Annable, T.; Buscall, R.; Ettelaie, R.; Shephered, P.; Whittlestone, D., Langmuir,
1994, 10, 1060.
123. Effing, J. J.; McLennan, I. J.; Van Os, N. M.; Kwak, J. C. T., J. Phys. Chem.,
1994, 98, 12397.
124. Niklas, Y. J.; Blankschtein, D., Langmuir, 1994, 10, 5312.
125. Shaw, K. G.; Leipold, D. P., J. Coat. Technol., 1985, 57, 63.
126. Schaller, E. J., Surf. Coat. Aust., 1985, 22, 6.
127. Nyström, B.; Thuresson, K.; Lindman, B., Langmuir, 1995, 11, 1994.
128. Moilliett, J. L.; Collie, B.; Black, W., “Surface Activity,” Spon London, 1961, 2nd
Edition.
129. “Surface Activity and Detergency,” (K. Durham, Ed.), MacMillan, London, 1961.
129(a). Giles, G., Solution Behavior of Surfactants, K. L. Mittal,; E. J. Fendher,
Eds., Plenum Press, New York, 1982, Vol. 1.
130. Rose, G. R. F.; Weatherburn, A. S.; Bayley, C. H., Textiles Res. J., 1951, 21, 427.
131. Corrin, M. L.; Lind, E. L.; Roginsky, A; Harkins, W. D., J. Colloid Sci., 1949, 4,
485.
132. Fava, A.; Eyring, H., J. Phys. Chem., 1956, 60, 890.
133. Tamamushi, B.; Tamaki, K., “Proceedings of the 2nd
International Congress of
Surface Activity,” Butterworths, London, 1957, Vol. – III, P. 449.
134. Tamamushi, B.; Tamaki, K., Trans Faraday Soc., 1959, 55, 1007.
135. Zettlemoyer, A. C.; Schneider, C. H.; Skewis, J. D., “Proceedings of the 2nd
International Congress of Surface Activity,” Butterworths, London, 1957, Vol.
III, P. 472.
136. Chattoraj, D. K.; Mahapatra, P. K.; Biswas, S., In “Surfactants in Solution,” K. L.
Mittal and Chattopadhyay, Eds., 1996, Vol. 12, P. 83.
137. Cuming, B. D.; Schulman, J. H., Austral. J. Chem., 1959, 12, 413.
138. Kaganovski, A. A., Colloid. J. (USSR), 1962, 24, 597.
139. Somasundaran, P.; Kunjappu, Joy. T., Innovations Mater. Procees. Using
Aqueous, colloid Surf. Chem. Proc. Top Symp. 1989, P. 31.

(31)
140. Somasundaran, P; Kunjappu, Joy. T., Colloids Surf. 1988, 37, 245.
141. Rannie, A. R.; Lee, E. M.; Simister, E. A.; Thomas, R. K., Langmuir, 1990, 6 (5),
1031.
142. Arnebrant, T., Baeckstroem, K., Joensson, B.; Nylander, J., J. Colloid Interface
Sci., 128, 303 (1989).
143. Wierer, K. A.; Dobias, B., In “Surfactants in Solution,” K. L. Mittal, Ed., Plenum
Press, New York and London Vol. 9, P. 359 (1989).
144. Somasundaran, P.; Chandra, P.; Turro, N. J.; Waterman, K. C., In “Surfactants in
Solutions,” K. L. Mittal, Ed., Plenum Press, New York and London, Vol. 9, P.
339 (1989).
145. Lindman, B.; Jonsson, B; kabalnov, A.; Olson, U.; Piculell L.; Tiberg, F., Abst.
Plenary Lect., 10th
Int. Sym. on “Surfactants in Solution,” Caracas, Venezuela,
1994, P. 5.
146. Martin, K.; Hellsten, E.; Klingberg, Anders, W.; Karisson, B. T., Gunvor, L.,
JAOCS, J. Amer. Oil. Chem. Soc., 1989, 66 (9), 1381.
147. Jurkiewicz, K.; Janust, W.; Sprycha, R.; Szczypa, J., in “Surfactants in Solution,”
K. L. Mittal, Ed., Plenum Press, New York, London, Vol. 9, P, 371. (1989).
148. Arshid, F. M.; Giles, C. H.; Melure, E. C.; Ogilicic, A.; Rose, T. J., J. Chem. Soc.,
1953, 67.
149. Arshid, F. M.; Giles, C. H.; Jain, S. K., J. Chem. Soc., 1956, 859.
150. Chattoraj, D. K.; Mitra, S. P., Indian J. Bichem. Biophys. 1977, 14, 1.
151. Mitra, S. P.; Chattoraj, D. K.; Das, M. N., Indian J. Biochem. Biophys. 1977, 14,
1001.
152. Das, M.; Chattoraj, D. K., J. Biol. Sci., 1984, 6, 689.
153. Sadhukhan, B; Chattoraj, D. K., Indian J. Biochem. Biophys. 1983, 20, 66.
154. Chattoraj, D. K.; Mitra, S. P., Indian J. Biochem. Biophys. 1977, 14, 7.
155. Mitra, S. P.; Chattoraj, D. K.; Das, M. N.; Sen, A., Indian J. Biochem. Biophys.
1978, 15, 153.
156. Mitra, S. P.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1978, 15, 239.
157. Bull, H. B.; Breese, K., Arch. Biochem. Biophys. 1979, 197, 199.
158. Privalov, P. L.; Mrevlishvili, G. M., Biofizika, 1967, 12, 19.

(32)
159. Kaivarainer, A.; Guryunov, A. A.; Sukhanova, G., Folia Biol. (Prague), 1984,
30(4) 221.
160. Edsull, J. T., in “The Proteins” (H. Neurath and K. Bailey, Eds.), 1st
Edition,
Acad. Press, New York, 1953, Vol. 1, P. 549.
161. Tanford, C., “Physical Chemistry of Macromolecules,” John Wiley and Sons.
Inc., New York, 1961.
162. Benoit, H.; Freund, L.; Spach, G., in “Poly. α-amino Acids,” (G. D. Fasman ed.),
Dekker, New York, P. 105.
163. Fraser, R. D. B.; Suzuki, E., in “Physical Principles and Techniques of Protein
Chemistry,” (S. Leach, Ed.), Part-B, Academic Press, New York, 1970, P. 213.
164. Miyazawa, T., In “Poly -amino Acids,” (G. D. Fasman, ed.), Dekker, New
York, 1967, P. 69.
165. Susi, H., in “Structure and Stability of Biological Macromolecules,” (S. N.
Timasheff and G. D. Fasman, Eds.), Dekker, New York, 1969, P. 575.
166. Kuntz, I. D., J. Amer. Chem. Soc., 1971, 93, 516.
167. Kuntz, I. D., J. Amer. Chem. Soc., 1971, 93, 514.
168. Kuntz, I. D.; Brassfield, T. S., Arch. Biochem. Biophys. 1971, 142, 660.
169. Kuntz, I. D.; Brassfield, T. S.; Law, G. D.; Purcell, G. V., Science, 1969, 163,
1329.
170. Chattoraj, D. K.; Bull, H. B., J. Colloid Interface Sci., 1971, 35, 220.
171. Kresheek and Gordon, C., Methods. Enzymol. 1986, 127, 141.
172. Gray, H. B.; Bloomfield, V. A.; Hearst, J. E., J. Chem. Phys., 1967, 46, 1493.
173. Hearst, J. E.; Stockmayer, H., J. Chem. Phys., 1962, 37, 1425.
174. Edward, J. T., J. Chem., 1957, 35, 571.
175. Ihart, M.; Stabo, A.; Goring, D. A. I., J. Chem. Soc. (A), 1968, 1500.
176. Neal, J. L.; Goring, D. A. I., J. Polym. Sci., 1969, 103.
177. Ramiah, M. V.; Goring, D. A. I., J. Polym, Sci. (C), 1965, 27.
178. SHHO, H., J. Amer. Chem. Soc., 1958, 80, 70.
179. Moulik, S. P.; Mondal, A. B.; Biswas, A. M.; Ray, S., J. Phys. Chem., 1986, 34,
856.
180. Moulik, S. P.; Mondal, A. B.; Gupta, S., Indian J. Chem. Sect. A, 1985, 24, 670.

(33)
181. Banerjee, P.; Chattoraj, D. K., J. Indian Chem. Soc., 1993, 70, 1.
182. Bradbury, J. H. in “Physical Principles and Techniques of Proteins Chemistry,”
(S. J. Leach, Ed.), Part-B, Academic Press, New York, 1970, P. 99.
183. Yang, J. T., Adv. Protein Chem., 1961, 16, 325.
184. Scheraga, H. A., “Protein Structure,” Acad. Press, New York, 1961.
185. Edsall, J. T., in “The Proteins,” (H. Neurath and K. Bailey, eds.), First Edition,
Part-B, Acad. Press, New York, 1953, Vol. 1, P. 549.
186. Langmuir, I., J. Amer. Chem. Soc., 1916, 38, 2221.
188. Gibbs, J. W., The Collected Works of J. W. Gibbs, Vol. I, New Haven, Yale
University Press, 1948.
189. Kono, S.; Kondo, S., Encyclopaedia of Physics, Vol. X, Berlin, Gottengen,
Heidelberg, 1960.
190. Defay, R.; Priggogine, I.; Bellemano, A., Surface Tension and Adsorption
(Translated by Everatt, D. H.), Longman, London, 1966.
191. Motumura, K., J. Colloid Interface Sci., 1978, 64, 348.
192. Goodrich, F. C., Trans. Faraday Soc., 1968, 64, 3403.
193. Eriesor, J. C., Arkiv. Kemia, 1966, 25, 331.
194. Rusanov, A. I., Kolloid Zhur. 1962, 24, 309.
195. Hanser, R. C., J. Phys. Chem., 1962, 66, 410.
196. Fowkes, F. M., J. Phys. Chem., 1962, 66, 385.
197. Tolman, R. C., J. Chem. Phys., 1948, 16, 758.
198. Guggenheim, E. A., Trans. Faraday Soc., 1940, 36, 398.
199. Verschaffelt, J. E., Acad. Roy. Belgiane. Bull Classes Sci., 22, 373, 390, 402
(1936).
200. Adam, N. K., Physics and Chemistry of Surfaces, 3rd
Edition, Oxford University
Press, London, 1941.
201. Andrade, J. D; Hlady, V., Adv. Polym. Sci., 1986, 79, 1.
202. Mosbach, K., Ed.; Methods in Enzymology, Academic Press, new York, 1987,
Vol. 135.
203. Norde, W.; Lyklema, J., J. Colloid Interface Sci., 1978, 66, 257.

(34)
209. Lyklema, J., Molecular Interactions in Affinity Chromatography, in : Affinity
Chromatography (Gribanau, T.C.J., Ed.), Elsevier, Amsterdam, 1982, pp. 11-27.
210. Hjerter, S., Adv. Chromatogr., 1980, 19, 111-123.
211. Porath, J., Chromatogr. Chromatgr. Rev., 1978, 159, 13.
212. Porath, J., Pure Appl. Chem., 1979, 51, 1549.
213. Vroman, L. and Leonand, E. F., eds. Behavior of Blood and Its Components at
Interfaces, Ann. N. Y., Acad. Sci., 1977, 283.
214. Bair, R. E., Ed., Applied Chemistry at Protein Interfaces, Adv. Chem. Ser., 1975,
145.
215. Cooper, S. L; Peppas, N. A., Biomaterials, Adv. Chem. Ser. 1982, 199.
216. Andrade, J. D., Surface and Interfacial Aspects of Biomedical Polymers, Andrade,
J. D., Ed., Plenum Press, New York, 1985, Vol. 2, Part-1.
217. Norde, W., Polym. Sci. Technology, 12B (Adhes. Adsorption Polym. Part B),
1980, 801.
218. Greig Russell, G.; Brooks, D. E., J. Colloid Interface Sci., 1981, 83, 661.
219. Ivarsson, B.; Lundstroem, I., CRC, Crit. Rev. Biocompat., 1986, 2(1), 1.
220. Sevastianov, V. I., CRC, Crit. Rev. Biocompt., 1988, 4(2), 109.
221. Norde, W.; Fraaye, J. G. E. M.; Lyklema, J., ACS Symp. Series, 1987, 343, 36.
222. Bull, H. B., Biochem. Biophys. Acta, 1956, 19, 464.
223. Chattoraj, D. K.; Bull, H. B., J. Amer. Chem. Soc. 1959, 81, 5128.
225. Sarkar, D.; Chattoraj, D. K., Colloids Surfs. 1994, 2, 411.
226. Sarkar, D.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1994, 31, 100.
227. Dillman, W. J.; Miller, I. F., J. Colloid Interface Sci., 1973, 44, 221.
228. Fair, B. D.; Jamieson, A. M., J. Colloid Interface Sci., 1980, 77(2), 525.
229. Matuszewska, B.; Norde, W.; Lyklema, J., J. Colloid Interface Sci., 1981, 82(2),

(35)
652.
230. Kutssoukos, p. G.; Mumme – Yong, C. A.; Norde, W.; Lyklema, J., Colloid
Surfs., 1982, 5, 93.
231. Hajra, S; Chattoraj, D. K., Indian J. Biochem. Biophys. 1991, 28, 114.
235. Van Dulm, P.; Norde, W.; Lyklema, J., J. Colloid Interface Sci., 1981, 82(1), 77.
236. Feg, L.; Andrade, J. D.; Hu, C. Z., Scanning Microscope, 1989, 3(2), 399.
237. Welin-Klintstroem, S.; Wikstroem, M.; Askendal, A.; Elwing, H.; Lundstroem, I.;
Karlsson, J.; Renvert, S., Colloids Surfs., 1990, 44, 51.
238. Horsley, D.; Herror, J.; Hlady, V.; Andrade, J. D., ACS, Symp. Series, 1987, 343,
290.
239. Lok, B. K.; Cheng, Y.; Robertson, C. R., J. Colloid Interface Sci., 1983, 91, 87.
240. Hlady, V.; Reinecke, D. R.; Andrade, J. D., J. Colloid Interface Sci., 1986, 111,
555.
241. Beissinger, R. L.; Leonand, E. F., ASAIO, J., 1980, 3, 60.
242. Chan, B. M. C.; Brash, J. L., J. Colloid Interface Sci., 1981, 82(1), 217.
243. Norde, W.; MacRitchie, F.; Nowicka, G.; Lyklema, J., J. Colloid Interface Sci.,
1986, 112, 447.
244. Brash, J. L.; Samak, O. M., J. Colloid Interface Sci., 1978, 65, 495.
245. Lundström, I.; Elwing, H., J. Colloid Interface Sci., 1990, 136.
246. Jennissen, H. P., J. Chromatogr. 1978, 159, 71-83.
247. Jennissen, H. P., L. Physiol. Chem., 1976, 357, 1727.
248. Jennissen, H. P.; Botzet, G., Int. J. Biologie Macromolecules, 1979, 1, 171.
249. Jennissen, H. P., Adv. Enzyme Reg., 1981, 19, 377.
250. Jennissen, H. P., Protein Adsorption Hysteresis in : Surface and Interfacial
Aspects of Biomedical Polymers, J. D. Andrade Ed., Vol. 2, Plenum Press, New
York, 1985, P. 295.
251. Norde, W.; Favier, J. P., Colloids and Surfaces, 1992.
252. Bohnert, J. L.; Horbett, T. A., J. Colloid Interface Sci., 1986, 111, 363.

(36)
253. Rapoza, R. J.; Horbett, T. A., J. Biomater Sci. Polym. Ed., 1989, 1, 99.
254. Rapoza, R. J.; Horbett, T. A., J. Colloid Interface Sci., 1990, 136, 480.
255. Rapoza, R. J.; Horbett, T. A., J. Biomed. Mater. Res., 1990, 24, 1263.
256. Ertel, S. I.; Ratner, B. D.; Horbett, T. A., J. Colloid Interface Sci., 1991, 147, 433.
257. Wahlgren, M. C.; Arnebrant, T., J. Colloid Interface Sci., 1991, 142, 503.
258. Wahlgren, M. C.; Arnebrant, T., J. Colloid Interface Sci., 1992, 148, 201.
259. Wahlgren, M. C.; Paulsson, M. A.; Arnebrant, T., Colloids Surf. A : Physicochem.
Eng. Aspects, 1993, 70, 139.
260. Wahlgren, M. C.; Arnebrant, T.; Astendal, A.; Welin - Klinström, S., Colloids
Surf. A : Physicochem. Eng. Aspects, 1993, 70, 151.
261. Krisdhasima, V.; Vinaraphong, P.; McGuire, J., J. Colloid Interface Sci., 1993,
161, 325.
262. Krisdhasima, V.; McGuire, J.; Sproull, R., J. Colloid Interface Sci., 1992, 154,
337.
263. Vinaraphong, P.; Krisdhasima, V.; McGuire, J., J. Colloid Interface Sci., 1995,
174, 351.
264. Sarkar, D.; Chattoraj, D. K., J. Colloid Interface Sci., 1996, 178, 1.
265. Traube, J., Annalen, 1891, 265, 27.
266. Guastalla, J.; J. Colloid Sci., 1956, 11, 623.
268. Haydon, D. A.; Taylor, F. H., Phil. Trans., 1960, 252, 225.
269. Ward, A. F. H.; Tordai, L., Rec. Trav. Chim., 1952, 71, 482.
270. Vignes, A., J. Chim. Phys., 1960, 966.
271. De Boer, J. H., The Dynamic Character of Adsorption, Oxford University Press,
London, 1953.
272. Haydon, D. A.; Taylor, F. H., Phil. Trans. Roy. Soc., London, A225, 253,
255(1960).
273. Chatterjee, A. K.; Chattoraj, D. K., J. Colloid Interface Sci., 1968, 26, 1.
274. Pal, P. P.; Chatterjee, A. K.; Chattoraj, D. K., J. Colloid Interface Sci., 1975,
52(1), 46.
275. Szyszkawaski, B. V., Z. Phys. Chem., 64, 385(1908).

(37)
276. Ronsen, M. L.; Aronson, S., Colloids and Surf. 1981, 3, 201.
277. Crisp, D. J., J. Colloid Interface Sci., 1956, 11, 356.
278. Daniel, S. G., Trans. Faraday Soc., 1951, 47, 1345.
279. Bull, H. B.; Breese, K., Arch. Biochem. Biophys. 1974, 161, 665.
280. Posner, A. M.; Anderson, J. R.; Alexander, A. E., J. Colloid Interface Sci., 1952,
7, 623.
281. Belts, J. J.; Pelhica, B. A., Trans. Faraday Soc., 1960, 56, 1515.
282. Gillap, W. R.; Weiner, N. D.; Gibaldi, M., J. Phys. Chem., 1968, 72, 2218.
283. Bull, H. B., Biochem. Biophys.Acta, 1956, 19, 464.
284. Bull, H. B., Arch. Biochem. Biophys. 1957, 68, 102.
285. Das, K. P.; Chattoraj, D. K., J. Colloid Interface Sci., 1980, 78, 422.
287. Hajra, S.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1991, 28, 114.
288. Hajra, S.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1991, 28, 267.
289. Nag, A.; Sadhukhan, B.; Chattoraj, D. K., J. Surface Sci. and Technol., 1988,
4(1), 91.
290. Cumper, C.; Alexander, A. E., Trans. Faraday Soc., 1950, 46, 235.
291. Hauser, E. A.; Swearingen, L. E., J. Phys. Chem., 1941, 45, 644.
292. James, L. K.; Ray, B. R., J. Colloid Interface Sci., 1972, 38, 477.
293. Ishii, T.; Maramatsu, M., Bull. Chem. Soc. Jpn., 1971, 44, 679.
294. Graham, D. E.; Phillips, M. C., J. Colloid Interface Sci., 1979, 70(3), 403.
295. Ward, A. F. H.; Tordai, L., J. Chem. Phys., 1946, 14, 453.
296. Cumper, C. W. M.; Alexander, A. E., Rev. Pure Appl. Chem., 1951, 1, 121.
297. MacRitchie, F.; Alexander, A. E., J. Colloid Sci., 1963, 18, 453.
300. Frisch, H. L.; Al-Madfai, S., J. Amer. Chem. Soc., 1958, 80, 3561.
301. Ghosh, S.; Bull, H. B., Biochem. Biophys. Acta. 1963, 66, 150.
302. Das, K. P.; Chowdhury, J.; Chattoraj, D. K., Indian J. Biochem. Biophys. 1981,
18, 387.
303. James, L. K.; Ray, B. R., J. Colloid Interface Sci., 1972, 38, 477.

(38)
304. Donaldson, T. L.; Boonstra, E. F.; Hammond, J. M., J. Colloid Interface Sci.,
1980, 74(2), 441.
305. Kiosseoglou, V. D.; Sherman, P., Colloid and Polym. Sci., 1983, 261, 502.
306. Bull, H. B., J. Amer. Chem. Soc., 67, 10(1945).
307. Pearson, J. T.; Alexander, A. E., J. Colloid Interface Sci., 27, 53(1968).
308. Ydenfreund and Becher, P., Monolayers, Edited by E. D. Goddard, Adv. in Chem.
Ser. No. 144 (Ammer. Chem. Soc., Washington D. C.) PP. 192(1975).
309. Samanta, A.; Chattoraj, D. K., Progress, Colloid and Polymer Sci., 68. 144(1983).
310. Samanta, A.; Chattoraj, D. K., “Properties of Surfactants in Solution (K. L. Mittal
and J. Bothorel, eds.), Plenum Press, New York (1986).
311. Samanta, A.; Chattoraj, D. K., J. Colloid Interface Sci., 116, 168(1987).
312. Hunter, J. R.; Kilpatrick, P. K.; Carbonell, P., J. Colloid Interface Sci., 137(2),
462(1990).
313. Duillard, R.; Lefebrre, J., J. Colloid Interface Sci., 139(2), 488(1990).
314. Joos, P.; Bleys, G.; Petre, G., J. Chem. Phys., 1982, 79, 387.
315. Joos, P.; Serrien, G., J. Colloid Interface Sci., 1989, 127, 97.
316. Bleys, G.; Joos, P., J. Phys. Chem., 1985, 89, 1027.
317. Burcik, E. J.; Joos, P., J. Colloid Interface Sci., 1950, 5, 421.
318. Rellaerts, E.; Joos, P., J. Phys. Chem., 1982, 86, 3471.
319. Van den Dogart, R.; Joos, P., J. Phys. Chem., 1979, 83, 2244.
320. Van Hansel, J.; Joos, P., Colloids Surfs. 1987, 24, 139.
321. Balaert, I.; Bleys, G.; Joos, P., J. Colloid Interface Sci., 1987, 115, 362.
322. Fowkes, F. M., J. Phys. Chem., 1963, 67, 1094.
323. Tornberg, E., J. Colloid Interface Sci., 1977, 60, 50.
324. Mysels, K. J., Langmuir, 1986, 2, 428.
325. Mysels, K. J., Langmuir, 1989, 2, 442.
326. Rasing, T.; Stehlin, T.; Shen, Y. R.; Kim, M. W.; Valink, P. Jr., J. Chem. Phys.,
1988, 85 (5), 3386.
327. Miller, R.; Kretzschman, G., Adv. Colloid Interface Sci., 1991, 37 (1-2), 97.
328. Borwarkar, R. P.; Wasar, D. T., Chem. Eng. Sci., 1988, 43 (6), 1323.

(39)
329. Bull, H. B., Introduction to Physical Biochemistry, Second ed. (F. A. Davis,
Philadelphia), PP. 277 (1971).
330. Klimenko, N. A.; Permilovsaya, A. A.; Trayasorukova, A. A.; Kaganovskii, A.
M., Kolloids, Zh., 37, 972 (1975).
331. Partyka, S.; Zaina, S.; Lindheimer, M.; Brun, B., Colloids Surfs. 12, 255 (1984).
332. Ghosh, L.; Das, K. P.; Chattoraj, D. K., J. Indian Chem. Soc., LXIII, 144 (1986).
333. Tiberg, F., J. Chem. Soc., Farady Trans, 92 (4), 531, 1996.
334. Tiberg, F.; Jönsson, B.; Lindman, B., Langmuir, 10, 3714 (1994).

POLYSACCHARIDE-SURFACTANT INTERACTION PART: 1
ADSORPTION OF CATIONIC SURFACTANTS AT
CELLULOSE-WATER INTERFACE
Chapter-2

POLYSACCHARIDE-SURFACTANT INTERACTION PART-1
ADSORPTION OF CATIONIC SURFACTANTS AT CELLULOSE-
WATER INTERFACE
Introduction
Recently, extensive studies have been made on the interaction of cationic and
anionic surfactants with natural and synthetic polymers.1-5
Such studies are found to be of
importance from fundamental and technological standpoints. In the last two decades,
thermodynamic and kinetic aspects of binding of cationic and anionic surfactants to
proteins5-8
and nucleic acids9
have been extensively investigated using various
experimental techniques. Compared to this, the study of interaction of ionic surfactants
with different types of polysaccharides has been undertaken in depth only in recent years
with many interesting results. The physicochemical principles involved in cellulose-
surfactant interactions are known for a long time to be closely associated with detergent
action and laundry cleaning of oiled fabrics.10-12
By use of equilibrium dialysis and other
techniques, the extent of binding of surfactants to soluble cellulose derivatives has been
investigated under different physicochemical conditions.13-16
Goddard et al.17,18
in their
reviews have extensively covered the techniques and principles used for the study of
interaction of surfactants with cellulose derivatives. Lindman and co-workers19-22
and
others23
have studied the interaction of ionic surfactants with hydrophobically modified
cellulose and other derivatives using different physicochemical conditions. Interactions of
surfactants with cellulose have been studied by few workers recently.24-26
Giles and
Arshid27, 28
from the adsorption of a series of chemically related solutes onto cellulose
and chitin have reported that cellulose is hydrophobic in nature.
In our present work, we have studied the adsorption of cationic surfactants of
varied chain lengths onto cellulose at different physicochemical conditions and in the
presence of different neutral electrolytes and urea. The role of hydration over the binding
interaction of surfactants has been critically examined. The changes of free energy due to
the binding of surfactants to cellulose under different physicochemical conditions have
been evaluated using an integrated form of the Gibbs adsorption equation. The nature of

(41)
surfactant-cellulose interaction has also been analyzed from thermodynamic
considerations.
Experimental Section
Materials:
Highly pure cellulose (TLC-Grade) was obtained from CSIR Centre for
Biochemicals, New Delhi. The cationic surfactants cetyltrimethyl ammonium bromide
(CTAB), myristyltrimethyl ammonium bromide (MTAB), and dodecyltrimethyl
ammonium bromide (DTAB) were obtained from Nakarai Chemicals Ltd. (Guaranteed
Reagent), Japan, and TCI (GR), Japan, respectively. The purity and critical micelle
concentration (cmc) of the surfactants have been determined by measurement of surface
tension of solutions as a function of surfactant concentration. The values of cmc for
CTAB, MTAB, and DTAB were found to be 0.89, 3.4, and 13.4 mM, respectively, which
agreed with those reported earlier.7,9,29
Other common electrolytes, acids, and urea used
were of analytical grade. Urea was recrystallized from warm alcohol before use. Double
distilled water was used all throughout the experimental work.
Before use, cellulose was dehydrated completely in a vacuum desiccator
containing concentrated sulfuric acid for 7 days, and then the dried cellulose was kept in
a desiccator containing anhydrous CaCl2.
Stock quantities of phosphate buffer solution of desired pH 6.0 and 8.0 and
acetate buffer of pH 4.0 were used in these experiments. The ionic strength of the
solution was maintained by direct addition of calculated amount of NaCl.
Adsorption Experiment:
In the adsorption experiments, a fixed amount, W (equal to 2 x 10-4
kg), of dried
cellulose was taken in different standard joint stoppered round bottom conical flasks
(capacity 100 mL). Then a fixed volume, V (equal to 20 mL), of solutions of different
molar concentrations ( t
C2 ) was taken into each flask. The flasks were then sealed and
shaken gently on a horizontal shaker for 24 h at constant temperature. The flasks were
taken away from the shaker and kept undisturbed for another 24 h. The temperature of the

Equilibrium and kinetics of surfactant adsorption

Equilibrium and kinetics of surfactant adsorption

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Equilibrium and kinetics of surfactant adsorption

Similar to Equilibrium and kinetics of surfactant adsorption (20)

More from Samares Biswas

More from Samares Biswas (17)

Recently uploaded

Recently uploaded (20)

Equilibrium and kinetics of surfactant adsorption