It's very concise and introductory presentation. I hope you will like it.

1. Seminar on Surface
and Interfacial
phenomenon
BY
GAJANAN V NAIK
M PHARM IST YEAR
Swami Ramanand teerth Marathwada University Nanded
School Of Pharmacy
UNDER GUIDANCE OF
DR. A. D. KSHIRSAGAR
ASS. PROFESSOR

2. What is micelle and how it forms?
• Ampiphile :
• A monomer is consist of
– Head : Hydrophilic
– Tail: Hydrophobic

3. What is micelle and how it forms?
• At low concentration: amphiphiles exist separately (subcolloidal
size)
• At high concentration: form aggregates or micelles (50 or more
monomers) (colloidalsize i.e. 50 Ǻ)
Micelle
At Low concentration
At High concentration
Bulk
interfaceinterface

4. What is micelle and how it forms?
• Critical micelle concentration (CMC ): The concentration of
monomer at which the micelles are formed.
• aggregation number : The number of monomers that aggregate
to form a micelle.
• From Gibbs equation of adsorption
Concentration Saturation Structure Surface tension
Below CMC Unsaturated Separated High
At CMC Saturated Micelles Reached final value
Above CMC More saturation Micelles Constant

5. Factors influencing CMC
• Structure of hydrophobic group. –
length of hydrocarbon chain is
Micelle size CMC
• Addition of Electrolyte
Micelle Size CMC
• Effect of Temperature
up to cloud point
Micelle Size CMC

6. Electrical Properties at Interfaces
• Particles dispersed in liquid media may become charged mainly
in one of two ways
– A. selective adsorption
– B. ionization of groups
• Two types of potential forms
– Nenrst
– Zeta

7. Zeta potential
• The zeta potential is defined as the
difference in potential between the
surface of the tightly bound layer
(shear plane) and the electroneutral
region of the solution.
• The potential located at the shear
plane bb’

8. Importance of Zeta potential
• The zeta potential has application in the stability of systems
containing dispersed particles.
• The zeta potential allows you to study the mechanism of
stabilization of a sample.
• The destruction of unwanted colloid.al dispersions

9. References
• A. N. Martin, Martin's Physical Pharmacy and Pharmaceutical
Sciences, 6th edition, p. 389-390.
• M.E. Aulton, Pharmaceutics science of dosage form design, 2nd
Edition, p. 88-89
• Leon Lachman, The Theory and Practice of Industrial Pharmacy,
3rd edition, p. 106