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1. NANOCOMPOSITES (NC) BASED
ON METALAND METAL OXIDE
NANOPARTICLES AND
MAGNETIC NANOPARTICLES
ADITYA BHARDWAJ

2. CONTENTS
1. Metal nanoparticles based nanocomposites (Page 3-49)
2. Metal oxide nanoparticles based nanocomposites (Page 50-79)
3. Magnetic nanoparticles (Page 80-106)

3. METAL NANOPARTICLES BASED
NANOCOMPOSITES

4. CONTENTS
• Introduction
• Nanocomposites based on metal nanoparticles
 Why metal nanoparticles are used as NC?
 Synthesis method of metal nanoparticles
• Types of metal nanoparticles based nanocomposites
 Polymer – metal nanoparticles nanocomposites
 Metal nanoparticles – CNT nanocomposites
 Metal nanoparticles – Ceramic nanocomposites
• Nanocomposites based on metal oxide nanoparticles
• Synthesis method of metal oxide nanoparticles
• Types of metal oxide nanoparticles based nanocomposites

5. INTRODUCTION
• Nanocomposites are composites in which at least one of the phases
shows dimensions in the nanometer range.
• Nanocomposites are a class of materials in which one or more phases
with nanoscale dimensions (0-D, 1-D, and 2-D) are embedded in a metal,
ceramic, or polymer matrix.
Types of nanocomposites
• Ceramic matrix nanocomposites
• Metal matrix nanocomposites
• Polymer matrix nanocomposites

6. NANOCOMPOSITES BASED ON
METAL NANOPARTICLES

7. WHY METAL NANOPARTICLES USED AS NC?
• Large surface to volume ratio
• Optical properties
 Surface plasmon resonance
• Quantum size effects

8. LARGE SURFACE TO VOLUME RATIO
Surface area increases
(A)
h>>d
h= d
h<<d
Wire Disc
(B)
Schematic of :(A) High surface area of nanomaterials for a given volume.
(B) Ratio of h and d determines shape of nanomaterial.

9. OPTICAL PROPERTIES
SURFACE PLASMON RESONANCE (SPR)
• SPR is process which takes place when there is coherent
oscillation of conduction band electrons upon interaction with
an electromagnetic field.
• It takes place when size of nanoparticle is smaller than
wavelength of incident radiations.
• It occurs mostly in case of metal nanoparticles such as gold
nanoparticles.
Figure: Schematic of
Plasmon oscillation for a
sphere, showing the
displacement of the
conduction electron charge
cloud relative to the nuclei.

10. Surface plasmon absorption of spherical nanoparticles and its size dependence.
(a) Excitation of dipole surface plasmon oscillation
(b) Optical absorption spectra of 22nm, 48nm, 99nm spherical gold nanoparticles
(S Link and M.A. El- Sayed, Int. Rev. Phys. Chem. 19, 409 (2000))

11. • The unique optical properties of nanomaterials also arise due to
quantum size effects.
• When size of nanocrystal is smaller than De-Broglie wavelength,
electrons and holes are spatially confined and electric dipoles are
formed, discrete energy levels are also formed.
• Similar to particle in box, energy separation between adjacent levels
increases with decreasing dimensions.
QUANTUM SIZE EFFECTS

12. Schematic illustrating discrete
electronic configuration in
(a) Bulk
(b) Thin films
(c) Nanowires
(d) Nanocrystal
(Cao, Guozhong. Synthesis,
properties and applications.
Imperial college press, London,
2004.)
• These changes arise through systematic transformations in density of
electronic energy levels as a function of size, and these changes result in
strong variations in the optical and electrical properties with size.
• The quantum size effect occurs mostly in case of semiconductor
nanoparticles, where band gap increases with decreasing size, resulting in
interband transition shifting to higher frequencies.

13. SYNTHESIS METHODS OF METAL
NANOPARTICLES
• Metal nanoparticles prepared by:-
•Top Down Approach (Physical methods)
• In this approach a bulk material and then break it into smaller pieces using
mechanical, chemical or other form of energy.
• Metal nps prepared by mechanical subdivision of metallic aggregates
and evaporation of a metal in a vacuum by resistive heating or laser ablation,
Photolithography, Electron beam lithography, Ball milling, etc.
• Bottom up approach (Chemical methods)
• In this approach, material is synthesized from atomic or molecular species
via chemical reactions, allowing precursor particles to grow in size.
• Metal nps prepared by chemical reduction of metal salts in solution, Sol-gel,
Hydrothermal and solvothermal process, Chemical vapor deposition, Inert
gas condensation, Colloidal methods, Microemulsion route etc.

14. INERT GAS CONDENSATION
• Widely used technique for metal nanoparticle synthesis.
• In IGC, metals are evaporated in ultra high vacuum chamber filled with helium or argon
gas at typical pressure of few hundreds Pascal. The evaporated metal atoms lose their
kinetic energy by collisions with the gas, and condense into small particles. These particles
then grow by Brownian coagulation and coalescence and finally form nano-crystals.
• Used for synthesis of gold - palladium nanoparticles also.

15. Preparation of metal nanoparticles by chemical reduction in
presence of (a) cationic surfactant (b) polymers (PVA, PVP)
CHEMICAL REDUCTION OF METAL SALTS

16. • Functionalization of metal nps with thiols, amines, phosphines and
bipyridyls further improve properties for specific applications.
Fig (a) left, shows a general scheme for exchange reaction bw alkanethiol monolayer protected
gold nps and various functional thiols. X and m are no of new and original ligands.

17. SOL-GEL PROCESS
• The sol-gel process is a wet-chemical technique that uses either a
chemical solution (sol short for solution) or colloidal particles (sol for
nanoscale particle) to produce an integrated network (gel).
• Metal alkoxides and metal chlorides are typical precursors. They
undergo hydrolysis and polycondensation reactions to form a colloid, a
system composed of nanoparticles dispersed in a solvent. The sol
evolves then towards the formation of an inorganic continuous network
containing a liquid phase (gel).
• Formation of a metal oxide involves connecting the metal centers with
oxo (M-O-M) or hydroxo (M-OH-M) bridges, therefore generating
metal-oxo or metal- hydroxo polymers in solution.
• After a drying process, the liquid phase is removed from the gel. Then,
a thermal treatment (calcination) may be performed in order to favor
further polycondensation and enhance mechanical properties.

18. MICROEMULSION
• Microemulsions are clear, stable, isotropic liquid
mixtures of oil, water and surfactant, frequently in
combination with a co -surfactant.
• The aqueous phase may contain salt(s) and/or other
ingredients, and the "oil" may actually be a complex
mixture of different hydrocarbons and olefins.
• The two basic types of microemulsions are direct (oil
dispersed in water, o/w) and reversed (water dispersed in
oil, w/o).

19. HYDROTHERMAL/SOLVOTHERMAL SYNTHESIS
• In a sealed vessel (bomb, autoclave, etc.), solvents can be brought
to temperatures well above their boiling points by the increase in
autogenous pressures resulting from heating. Performing a chemical
reaction under such conditions is referred to as solvothermal
processing or, in the case of water as solvent, hydrothermal processing.
Effect of time and temperature on size and morphology of ZnO–SnO2 nanocomposite A)
160οC for 30min B) 160οC for 60min C) 160οC for 4h D) 160οC for 12h E) 180οC for 30min
F) 200οC for 12h
Wang et.al, Advanced Functional materials. Volume 17.2007.59-64

20. TYPES OF METAL NPS BASED
NANOCOMPOSITES
• TYPES OF METAL NPS NANOCOMPOSITES
1. Metal nanoparticles - Polymer Nanocomposites
2. Metal nanoparticles - CNT Nanocomposites
3. Metal nanoparticles - Ceramic nanocomposites

21. METAL NPS- POLYMER NANOCOMPOSITES
• Polymer nanocomposites, in particular, are composite materials in which
nanoscopic inorganic particles, with atleast one dimension in the nanoscale
regime, are dispersed in a polymeric matrix in order to alter or improve the
properties of the polymer.
• Based on type of nanofillers, polymer nanocomposites can be classified as:-
(i) particles (e.g. minerals, metal nanoparticles)
(ii) sheets (e.g. exfoliated clay stacks)
(iii) fibres (e.g. carbon nanotubes or electrospun fibres)

22. • Polymers are attached to surface of nanoparticles via covalent bond
or coordination bond.
• Attachment of metal nanoparticles to synthetic polymers adds film-
forming properties to the metal nanoparticles and also provides the
opportunity for microphase separation between the metal nanoparticles
and the polymer matrix.
• Why nanoparticles based fillers used?
• Small size of nanoparticles used as filler- so less scattering will take
place, composites with altered electrical or mechanical properties that
retain optical clarity can be made.
• due to small size, no large stress concentrations created and so ductility
of polymer is not affected.
• Small size leads to unique properties, For example, single-walled
nanotubes are essentially molecules, free from defects, and have a modulus
as high as 1 TPa and strengths that may be as high as 500 GPa. Single-
crystal particles that are optically active, but are unmanageable on the
macro scale can be combined in a polymer to achieve the optical gain of
the material and the ease of processing afforded by the polymer.

23. • Polymer-embedded nanostructures are potentially useful for a number of
technological applications, especially as advanced functional materials
(e.g., high-energy radiation shielding materials, microwave absorbers,
optical limiters, polarizers, sensors, hydrogen storage systems, etc.) .
• In addition to the intrinsic nanoscopic material properties and the
possibility to make transparent metal–polymer combinations, these
materials are interesting also because the presence of a very large filler–
matrix interface area can significantly affect the polymer characteristics
(e.g., glass transition temperature, crystallinity, free volume content, etc.),
allowing the appearance of further technologically exploitable mechanical
and physical properties (e.g., fire resistance, low gas diffusivity, etc.).

24. SYNTHESIS OF POLYMER NANOCOMPOSITE
(i) Solution casting - In solvent casting, the polymer and the nanofiller
are dispersed in a suitable common solvent and thoroughly mixed by
ultrasonication. The solvent is subsequently allowed to evaporate to
leave behind a thin film of the polymer nanocomposite.
(ii) Melt blending - In the case of melt blending, an extruder or an
internal mixer is used. The polymer and the nanofiller are added in
the extruder and subjected to intensive mixing till a uniform,
homogeneous matrix is obtained.
(iii) In-situ polymerization -The in-situ polymerization method
involves mixing of the nanoreinforcement with the monomeric or
oligomeric precursor of the polymer. Once uniform dispersion is
achieved, the polymerization is carried out by using a suitable agent
such as a catalyst, a radical initiator or by using high energy
radiation sources such as gamma and Electron beam.

25. • Other widely used methods for manufacturing composite parts are wet
lay-up, pultrusion, resin transfer molding (RTM), vacuum assisted resin
transfer molding (VARTM), autoclave processing, resin film infusion
(RFI), prepreg method, filament winding, fiber placement technology, etc.
• Radiation curing of a polymeric material involves the
use of radiation to generate radicals, which
subsequently result in cross linking to generate a
polymeric matrix of inter connected polymeric chains.
A typical radiation curable formulation comprises of
(a) a multifunctional monomer or oligomer such as
urethane acrylates,
(b) reactive diluents to optimize the viscosity and to
serve as a cross linking agent
(c) nanofiller.
• The thoroughly homogenized reaction mixtures
are exposed to a radiation source till the
formulation converts into a non-tacky, uniformly
cross linked, cured matrix, with the polymer
chains held together by the multifunctional
reactive diluent molecules acting as cross linkers.

26. SYNTHESIS METHODS OF
METAL NPS- POLYMER NANOCOMPOSITES
1. Ex situ approach, in which metal nanoparticles are produced, often by
some chemical approach or vapor deposition, then introduced into the
polymer, which may be a polymer solution, liquid monomer, dissolved
polymer solution or polymer powder, for example, by adding
nanoparticles during polymerization.
2. In situ approach, in which the metal nanoparticles are grown within the
polymer. This can be through the chemical reduction of a metallic
precursor that has been already dissolved in the polymer , thermolysis
decomposition , photolysis decomposition , photochemical preparation,
incorporation during polymer electrosynthesis or nanoparticle formation
during polymerization
• The ex-situ techniques for the synthesis of metal/polymer nanocomposites
are frequently preferred to the in situ methods because of the high optical
quality that can be achieved in the final product

28. PROPERTIES
• Mechanical properties
• The nanoparticle size, particle–matrix interface adhesion, and loading
amount strongly influence the mechanical properties of nanoparticle-
reinforced polymer composites.
• The nanoparticles readily enhance Young’s modulus of polymer matrices,
which is due to higher stiffness of nanoparticles as compared to pure
polymer.
• The stress transfer mechanism plays an important role in the
nanoparticle-reinforced polymer nanocomposites. The strength of the
polymer nanocomposites mainly depends on the stress transfer between
the polymer matrix and the nanoparticles. The strong interfacial adhesion
effectively improves the stress transfer mechanism from particles to
polymer matrix, resulting in an increase in strength of the polymer
nanocomposites.

29. • Strong interfacial adhesion between metal nps and polymers also improves
mechanical properties. For better adhesion, modification with suitable
coupling agents is beneficial.
• Chatterjee et al. observed that dispersion of Ag nanoparticles into a
hydrophobic polymer matrix significantly enhanced the mechanical
properties of the nanocomposite films. The polymer/Ag nanocomposites
film (containing 0.65% of Ag) , displayed storage modulus that are
up to 130% higher. This is due to the high surface area of the polymer
coated Ag nanoparticles in the polymer matrix and Van Der Waal's
attraction force between surface of Ag nanoparticles and host polymer
matrix.

30. Storage modulus versus
temperature plots of PMMA
and PDMA-b-PMMA-b-
PDMA-Ag/PMMA
nanocomposite films.
Inset of Figure shows plot of
storage modulus with
increasing amount of added
Ag nanoparticles.
Chatterjee et al. Polymer Composites 30.6 (2009): 827-834.

31. THERMAL PROPERTIES
• The loading amount of the nanoparticles is an important parameter for the
thermal properties of the polymer matrix.
• Mandhakini et al. studied the tribological properties of epoxy
nanocomposites with the addition of different weight ratios of alumina
nanoparticles. The authors observed that the addition of alumina content
from 1 to 5 wt% increases the Tg of the polymer nanocomposites, which
is attributed to decrease in the polymer–polymer interface and restricted
chain mobility of polymer segments resulting from good adhesion
between the nanoparticles and the surrounding polymer matrix. At a
higher loading (10 wt%), a decrease in Tg was observed, due to phase
segregation.
• Valmikanathan et al. observed that incorporation of Pd nanoparticles
(18.4 wt%) in Polycarbonate matrix improves the thermal stability of the
nanocomposite for both in-situ (425οC to 455οC) and ex-situ process (425οC
to 475οC)

32. ELECTRICAL PROPERTIES
• Polymeric materials are non conductors of electricity, so incorporation of
metal nanoparticles within the polymers can significantly enhance the
electrical properties of the nanocomposite formed.
• Luechinger et al. found that for a cobalt-nanoparticle-reinforced
polyethylene oxide composite this percolation level could be as low
as 1–2%. At this level the authors found that conductivity jumped
several orders of magnitude, but this depended on the processing
technique since it controlled the distribution of the nanoparticles.
• Electrical conductivity (σ, ohm-1 cm-1) of polymeric composites filled by
dispersed metals (Ag, Ni, Cu, Al) depends on the filler volume content ϕ and
the dependence is usually nonlinear because the small metal particles form
monolayers on the large particles of the polymer.

33. • Electroconductive properties appear themselves only at a given
component ratio in the metal– polymer system, when in the polymeric
matrix the conductive channels (i.e. the continuous chains of metal-
containing clusters) in polymer matrix there are the conductivity channels.
• There is some critical value (ϕcr) of filler volume content (the value is
called the percolation threshold), above which (at ϕ > ϕcr) an abrupt rise of
the electrical conductivity is observed
• The percolation threshold value linearly depends on the maximum filling
F (i.e. a theoretical limit of the system filling):
ϕcr = XcrF ,
where Xcr is a critical parameter defined by the number of conductive knots
in the solid body lattice. F is 0.64 for monodispersed spherical particles of
every size statistically packed into a composition

34. APPLICATIONS
1. Biomedical applications - Tissue engineering, drug delivery, detection of
pathogens, biosensors, cancer hyperthermia, antibacterial agents
2. Catalysis
3. Fuel cells
4. Solar cells
5. Electronic memory devices- Memory device based on polystyrene film
containing gold nanoparticles and 8-hydroxyquinoline sandwiched between two
metal electrodes. The as prepared device, which is in a low-conductivity state,
displays an abrupt transition to a high-conductivity state under an external bias of
2.8 V. These two states differ in conductivity by about four orders of magnitude.
Applying a negative bias of 1.8 V causes the device to return to the low-
conductivity state. The electronic transition is attributed to the electric-field-
induced charge transfer between the gold nanoparticles and 8-hydroxyquinoline.
Programmable polymer
thin film and non
volatile memory device.
Quyang et al,. Nature
materials 3.12 (2004):
918.

35. METAL NPS-CNT NANOCOMPOSITES
• The combination between CNT and metal nanoparticles is much
interesting because metal exhibits very important optical and
electronic properties that can be improved by the mix with CNT.
• Ag/ CNT nanocomposite can be used as catalyst, optical limiters,
advanced materials.
• Metal/CNT composites were prepared by sequence of mixing,
evaporation and drying processes that lead to the formation of
composites where a uniform network of metal nanoparticles is weaved
on a CNT matrix. Metal nanoparticles were produced by laser ablation.

36. SYNTHESIS OF METAL NP- CNT
NANOCOMPOSITE
1. Electrochemical deposition
2. Electroless deposition
3. Dispersion of metal nanoparticles on functionalized CNTs
4. Physical methods

37. ELECTROCHEMICAL DEPOSITION
• Electrochemistry is powerful process for deposition of metal nps as it
enables effective control over nucleation and growth rate of nps.
• Noble metal nps/CNT nanohybrids are obtained via reduction of noble
metal complexes, such as H[AuCl4] , H2[PtCl4] , (NH4) 2 (PdCl4).
• CNTs typically do not react with the noble metal salts but act as molecular
conducting wire and supports for the deposition of noble metal NPs.
• Importantly, the size of the noble metal NPs and their distribution on the
sidewalls of CNTs can be controlled by the concentration of the noble metal
salts and various electrochemical deposition parameters, including
nucleation potential and deposition time.
• Noble metal nps with high purity and good adhesion is formed.
• He et al. electrochemically deposited Pt or Pt-Ru nps on surface of substrate
grown CNTs with diameter 60-80 nm. deposition took place
potentiostatically at −0.25 V from a solution containing chloroplatinic acid
or ruthenium chloride and chloroplatinic acid in 0.5M H2SO4.

38. ELECTROLESS DEPOSITION
• Electroless deposition method relies on a chemical, as opposed to
electrochemical reduction process, whereby a chemical species whose
redox potential is suitably lower than that of the metal species being
reduced provides the driving force for the reaction.
• Dai et al. proposed direct redox reaction occurring between metal ions and
CNTs. Au, Pt NPs could be spontaneously deposited on SWCNTs with high
selectively when SWCNTs were immersed into corresponding metal salt
solutions.
• The main drawback is that metal ions can be transformed to metal nps on
CNT support only when redox potential of metal ions is higher than CNT.
Consequently Cu2+ (+0.34 V), Ag+ (+0.79 V) ions cannot be deposited on
CNT surface by electroless deposition due to lower redox potential than
CNTs (0.80 V). Method called substrate-enhanced electroless deposition
(SEED), was developed to spontaneously deposit Au, Pd, Pt metal with low
redox potential could deposit onto the CNTs by supporting the CNTs on a
metal substrate with a lower redox potential than that of the metal ion. CNTs
are not the reducing agent in this method and they only act as cathodes and
templates for metal deposition from the corresponding metal salts

39. • Lorencon et al. reported a one-pot method to synthesize noble metal
NPs/CNTs nanohybrids by a redox reaction between metal ions and
reduced CNTs .
• This process involved two steps.
1. First, CNTs were reduced by metallic Na in an aprotic organic solvent,
which could obtain a solution of exfoliated negatively charged CNTs.
2. In the second step, metal cations were added to the solution and
immediately reduced upon contact with the CNTs, because of excess
of electrons, forming metal NPs along the CNTs surface. This method
is very straightforward and also does not require metal ion with a
redox potential higher than that of CNTs.
• They successfully anchored Au and Pd NPs to the surface of MWCNTs and
SWCNTs by this method without any surfactants or previous CNT surface
functionalization.

40. DISPERSION OF METAL NPS ON
FUNCTIONALIZED CNT
• CNTs without surface modification has insufficient binding sites for
anchoring precursors of metal nps or metal ions, which leads to poor
dispersion and large nanoparticles at large concentrations.
• CNTs could be functionalized by:-
a) Covalent attachment of functional groups through forming covalent bonds
to Π conjugated skeleton of CNTs.
b) Non covalent absorption such as Π – Π stacking, hydrophobic interaction,
electrostatic interaction, or wrapping of polymers or functional molecules.
• Niu et al. firstly grafted amine-terminated ionic liquids (NH2 -IL) to the
carboxyl-functionalized MWCNTs (MWCNTs-COOH) by formation of the
amide linkage between MWCNTs-COOH and NH2 -IL. Then the gold salt
[AuCl4
-] was absorbed on the ionic liquid-functionalized CNTs via
electrostatic interaction and ionic exchange and Au NPs with uniform
dispersion and narrow size distribution were easily produced by in situ
reduction on CNTs. Using imidazolium - salt-based ionic liquids (IS-ILs) as
linkers, Guo et al. further prepared CNTs/IS-ILs/Pt NPs nanohybrids.

41. PHYSICAL METHODS
• Physical methods, including sputtering deposition, ion and electron beam
irradiation deposition and evaporation deposition are widely used.
• Sputtering deposition is an efficient method for the synthesis of noble metal
NPs/CNTs nanohybrids. Using this method, uniform-size noble metal NPs
can be conveniently deposited on the external wall surface of CNTs, by
selecting appropriate metal cathodes, and by controlling the current and
sample exposure time. Roy et al. deposited Pt NPs with the particle size of
3-5nm uniformly onto the surface of the vertically aligned carbon nanotubes
(VACNT) by DC sputtering system.
• Ion or electron beam irradiation can also be used, method has advantage of
homogenous reduction and nucleation leading to stable and small size nps.
• Wang et al. prepared Pt/CNT nanohybrid of size 2.5-4nm, Pt was deposited
onto CNT by γ irradiation method.
• Evaporation methods such as thermal evaporation deposition and electron
beam evaporation deposition have advantage of controlling size and
covering density of nps on CNT surface by varying evaporation temperature
and deposition time. Gingery et al. synthesized Au/MWCNT in size 4-150
nm by thermal deposition, electron beam was used for Rh,Pt /SWCNTs.

42. APPLICATIONS
1. Heterogenous catalysis
2. Fuel cells and electrocatalyst
3. Chemo/mechanical biosensor
4. Electronic devices – sink and solders (good thermal properties), Antennas
(electrical properties and stiffness)
5. Aerospace and automotive industries- structural radiator, gears, aircrafts fin,
Cylinder liner, disk brake and calipers.
6. Manufacturing of tennis, badminton racquets, bicycle frames

43. Wei et al, In case of PEMFCs, Pt
nps on CNT support increase
efficiency of fuel cell as they
increase the electron pathway, as
when Carbon black support is used
the current conduction decreases
due to inaccess of electron to
current collector
Chen et al, In case of DMFCs, Pt nps on CNT
support were stabilized by ionic liquid polymer thin
film, increase stability, methanol electrooxidation
has been improved obviously due to mechanical
isolation of PIL thin layer between PtNPs,
electrostatic and coordinating action between
PtNPs and N-heterocyclic cations of ILs to inhibit
the migration and agglomeration of PtNPs

44. METAL NPS-CERAMIC
NANOCOMPOSITES
(a) Nanoparticles embedded in matrix
(b) Nanowires embedded in matrix
(c) Nanometer size multilayer thin film

45. METHODS OF PREPARATION
1. Co-sputtering- metal nps embedded in ceramic- Si/SiO2 and Pt/TiO2 or
metal nps in semiconductor matrix- Ag/Si nanocomposite.
• Metal and ceramic targets used together in sputtering.
• Size controlled by deposition rate and substrate temperature.
2. Co-evaporation- superparamagnetic Fe2O3/Ag nanocomposites
• Used with gas condensation for Ag/Fe alloys, Fe embedded in Ag
matrix, followed by oxidation to convert Fe to Fe2O3.
3. Powder blending or high energy mechanical milling plus powder
consolidation- Mg/SiC, Plastic deformation, fracturing, cold welding
helps in breakdown of nanoparticles.

46. Eg: Cu-20 wt% W nanocomposite
I. Few W particles incorporated in Cu particles
II. After further milling, work hardening of Cu-W phases occur, W
particles are deformed, fractured and incorporated in Cu particles.
III. Less than 5nm size, W particles dissolve in Cu and Cu-W solid
solution is formed or Cu-W amorphous phase is formed.
• Similarly Cu-Al-CuO, Cu- Al2O3, Ni- Al2O3 NC can be formed.
• Microstructural evolution
of powder particles during
high energy mechanical
milling of Cu–20wt% W
powder.
• The dark phase is Cu and
the bright phase is W.

47. 4. Partial reduction of a ceramic or partial oxidation of metal
a) Partial reduction of ceramic
I. Nanostructured ceramic powder produced by precipitation
II. Ceramic powder reduced using mixture of argon and hydrogen, to
convert ceramic phase to metal nanoparticles.
III. Ceramic phase is oxide of inactive metals such as Cu, W, Ni.
IV. Then sintering and hot pressing forms the nanocomposite.
V. Used to prepare ceramic matrix nanocomposite powder.
b) Partial oxidation of metal
I. Alloy powder produced using atomization or mechanical alloying
II. Then powder is oxidized to bring Al element out of alloy to form oxide
nanoparticles.
III. The formation of oxide nanoparticles require nucleation and growth in
solid state.
5. Decomposition and devitrification- decomposing SiO or FeO or
crystallizing amorphous alloy such as Na-Ti-C or Nd2 (Fe, Co, Nb)15B
6. Ion implantation- Fe-Al nanocomposites, Pb - Sn nps in Al matrix,
Pb – Cd nanoparticles in Si matrix.

48. APPLICATIONS
• Recently a Japanese steel maker, NKK, has developed a steel-based
metal–ceramic nanocomposite which demonstrates high strength
(yield strength = 780MPa) and much improved ductility and formability
This steel-based nanocomposite is to be used for making automotive
underbody parts such as suspensions.
• Alumina ceramics (wafers or tubes) are generally used as substrates to support
sensing films. In the ceramic tube-based device, a piece of heating wire is
placed in the interior of the ceramic tube, while, in the ceramic wafer-based
device, heating paste is placed on the backside of the ceramic wafer.
Device structure for gas sensing based on Ceramic wafer/ceramic tube substrate

49. REFERENCES
1. Camargo, Pedro Henrique Cury, Kestur Gundappa Satyanarayana, and Fernando
Wypych. "Nanocomposites: synthesis, structure, properties and new application
opportunities." Materials Research 12.1 (2009): 1-39.
2. Cao, Guozhong. Nanostructures and nanomaterials: synthesis, properties and
applications. World Scientific, 2004.
3. Shodhganga.inflibnet.ac.in Introduction to metal np and polymeric nanoparticles
4. https://shellzero.wordpress.com/2012/05/14/inert-gas-condensation-method/
5. Naka, Kensuke, and Yoshiki Chujo. "Nanohybridized synthesis of metal nanoparticles
and their organization." Nanohybridization of Organic- Inorganic Materials. Springer
Berlin Heidelberg, 2009. 3-40.
6. Nanoparticle Synthesis Jimmy C. Yu Department of Chemistry Environmental Science
Programme.
7. Lateef, Ambreen, and Rabia Nazir. "Metal Nanocomposites: Synthesis, Characterization
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2004.

50. METAL OXIDE NANOPARTICLES
BASED NANOCOMPOSITES

51. CONTENTS
• Introduction
• Synthesis of metal oxide nanoparticles
• Types of metal oxide nanoparticles based nanocomposites
 Metal oxide nanoparticles- polymer nanocomposites
 Metal oxide nanoparticles- CNT Nanocomposites

52. INTRODUCTION
• Metal based elements can form number of oxide compounds with different
geometries that exhibit metallic, semiconducting or insulating
characteristics.
• Oxide nanoparticles can exhibit unique physical and chemical properties
due to their limited size and a high density of corner or edge surface sites.
• Particle size plays important role in 3 important properties of oxide nps:
1. Structural characteristics- lattice symmetry and cell parameters. Bulk
oxides are robust with well defined crystal geometries. For mechanical or
structural stability np must have low surface free energy. Intrinsic and
extrinsic strain must be also be considered, non stoichiometry, interactions
between solvent and substrate can induce structural defects.
2. Electronic properties of oxide- quantum size effect-discrete energy levels,
which lead to electron shifts and change in band gap.
3. Physical and chemical properties- In bulk, oxide have wide band gap and
low reactivity, but as size of nps decrease, band gap changes which causes
change in chemical reactivity and conductivity. Surface properties also play
key role, less vacancies, more adhesion to substrate surface of nanoparticle.

53. SYNTHESIS OF METAL OXIDE NANOPARTICLES
1. Coprecipitation reactions involve the simultaneous occurrence of nucleation,
growth, coarsening, and/or agglomeration processes.
• Coprecipitation reactions exhibit the following characteristics:
i. The products are generally insoluble species formed under conditions of high
supersaturation.
ii. Nucleation is a key step, and a large number of small particles will be formed.
iii. Secondary processes, such as Ostwald ripening and aggregation, dramatically
affect the size, morphology, and properties of the products.
iv. The supersaturation conditions necessary to induce precipitation are usually the
result of a chemical reaction.
xAy+ (aq) + yBx- (aq) AxBy (s)
• Typical coprecipitation synthetic methods:
(i) Metals formed from aqueous solutions, by reduction from nonaqueous solutions,
electrochemical reduction, and decomposition of metallorganic precursors;
(ii) Oxides formed from aqueous and nonaqueous solutions;
(iii) Metal chalconides formed by reactions of molecular precursors;
(iv) Microwave/sonication-assisted coprecipitation.

54. Coprecipitation method - Synthesis of Zno nanoparticles
Syadhameed et al. J. Mater. Chem. B, 2013, DOI: 10.1039/C3TB21068E [2]

55. 2. Sol-Gel process – Metal oxide formed via hydrolysis of precursors,
followed by condensation, polymerization, drying and calcination
Example: TiO2 nanoparticle-mediated mesoporous film by sol-gel processing
TiO2 nanoparticle mediated
mesoporous film (Yu, J.C et
al. Chem Mater. 2004,
16,1523) [3]

56. 3. Microemulsion or direct or inverse micelles
(Kumar, et al. RSC Publishing 2013, DOI: 10.1039/c3ra23455j [4]
represent an approach based on the formation of micro/nano-reaction vessels under a
ternary mixture containing water, a surfactant and oil. Metal precursors on water will
proceed precipitation as oxo-hydroxides within the aqueous droplets, typically leading to
monodispersed materials with size limited by the surfactant-hydroxide.
contact

57. 4. Solvothermal synthesis
5. Template/ Surface derivatized methods- in this method we use two type of
templates (a) Soft templates such as surfactant and (b) Hard templates such
as porous solids or carbon or silica.
6. Microwave assisted synthesis, sonochemical synthesis
7. Chemical vapor deposition- oxides with homogenous structure and size are
formed, these include Thermal CVD, Plasma assisted CVD,photo CVD,etc.
PLASMA
ELECTRODE
ELECTRODE
WAFER
HEATER
RF POWER INPUT
GAS OUTLET
GAS INLET
Plasma CVD for SiO2 nanoparticles

58. TYPES OF METAL OXIDE NANOPARTICLES
BASED NANOCOMPOSITES
1. Metal oxide np - polymer nanocomposite
2. Metal oxide np - CNT nanocomposite

59. METAL OXIDE NP-POLYMER
NANOCOMPOSITE
• Nanoparticle (NP) addition into polymers produces nanocomposites known
to improve mechanical strength, resistance to wear, and thermal stability.
• Polymers are good electrical insulators but we can modify the property by
appropriate combination with metal oxide nanoparticles. This is because of
high surface to volume ratio of metal oxide nanoparticles.
• The properties change with dispersion state, geometric shape and size of
nanoparticles.

60. SYNTHESIS METHODS
1. Direct mixing or blending of polymer and metal oxide nanoparticles,
either as discrete phase (melt mixing) or solution phase (solution mixing).
2. Sol-gel process, which starts with molecular precursor at ambient
temperature and then forms a metal oxide framework by hydrolysis and
condensation.
3. In-situ polymerization of monomers in presence of metal oxide
nanoparticles.

61. DIRECT MIXING OR BLENDING
• Blending is the simplest method of preparing polymer/metal oxide nanocomposites.
It is popular method as there is no limitation on the nature of the NPs and host
polymers used. According to the conditions, blending can be either melt blending or
solution blending.
• The effective dispersion of nps in polymer is key step in process.
• The strength of melt blending is the large quantity of material that can be produced
by extrusion, and most polymer blends are produced commercially in this way.
• Melt blending offers a number of appealing advantages, such as no requirement for
a solvent, ease of processing with conventional blending devices such as extruders,
relatively low cost, and being environmentally sound.
• Hong et al. prepared LDPE-ZnO nanocomposites using this technique.[8]

62. • Solution blending is a liquid-state powder processing method that produces a good
molecular level of mixing and is used widely in material preparation and
processing.
• The benefits of solution blending include the rigorous mixing of the inorganic filler
with the polymer in a solvent, which facilitates filler NP de-aggregation and
dispersion.
• This method consists of three steps:
a. dispersion of the filler NPs in a suitable solvent,
b. mixing with the polymer (at room temperature or elevated temperature),
c. recovery of the nanocomposite by precipitating or casting a film.
• Both organic and aqueous media have been used to produce nanocomposites. In
this method, the dispersion of filler NPs can be achieved by magnetic stirring, shear
mixing, reflux or, most commonly, by ultrasonication.
• Polystyrene (PS)/ZnO nanocomposites were prepared by solution mixing in
N,N- dimethylacetamide, followed by film casting.[9]

63. SOL-GEL PROCESS
• Sol–gel process is used because of its capability to control the miscibility between
organic and inorganic components at the molecular level.
• The term sol–gel is associated with two reaction steps: sol and gel. A sol is a
colloidal suspension of solid particles in a liquid phase and a gel is the
interconnected network formed between the phases.
• The metal reactivity, amount of water, solvent, temperature, and the use of
complexing agents or catalysts are the main reaction parameters. Whether to use
a catalyst or not depends on the chemical nature of the metal atom and steric
hindrance of the alkoxide group.
Preparation of
TiO2–polymer
nanocomposites via the in-
situ sol–gel route [10].

64. IN-SITU POLYMERIZATION
• Ex-situ processes generally suffer from the high agglomeration tendency of NPs
because the NP agglomerates are difficult to destroy, even using high external shear
forces.
• In-situ polymerization methods have been developed to overcome this problem. In-
situ polymerization involves the dispersion of inorganic fillers directly in a monomer
or monomer solution and the subsequent polymerization of the monomer dispersion
using standard polymerization techniques.
Formation of PS/TiO2 nanocomposites in a single step [11]

65. MECHANICAL PROPERTIES
• The nanoparticle size, particle–matrix interface adhesion, and loading
amount strongly influence the mechanical properties of nanoparticle-
reinforced polymer composites. The nanoparticles readily enhance Young’s
modulus of polymer matrices, which is due to higher stiffness of
nanoparticles as compared to pure polymer.
• Xiaong et al. observed that increasing TiO2 content caused an increase of
hardness (from 0.030 GPa for the pure polymer and 0.198 GPa for a TiO2
content of 10 wt %) and Young’s modulus (from 2.83 GPa for the pure
polymer and 4.98 GPa for a TiO2 content of 10 wt %). [13]
• Jeziorska et al. developed low-density polyethylene (LDPE)/ SiO2 NC via
melt extrusion method, studied the mechanical properties of the composites
with the effect of silica size, functionality, and compatibility. It was observed
that the addition of modified silica and glycidyl -methacrylate- grafted
ethylene/ n-octene copolymer (EOR-g-GMA) enhanced the tensile strength,
modulus, and impact strength due to better dispersion of SiO2 nanoparticles
and increased compatibility between silica and the LDPE matrix [14]

66. THERMAL PROPERTIES
• Polymers are poor conductors of electricity, so by making its composite
with metal oxide nanoparticles, we can decrease the value of polymer
degradation temperature and make a thermally stable nanocomposite.
• Laachachi et.al. compared the thermal stability of the PMMA by doping
equal amount of TiO2 and Fe2O3 (5 wt%) and observed with help of onset
degradation temperature (295οC for TiO2, 275οC for Fe2O3), that former
imparts better stability than the later.
TGA curves for pure PMMA,
PMMA- Fe2O3 and PMMA- TiO2
nanocomposites at 5 wt% of Fe2O3
and TiO2 under air
(heating rate: 10οC min-1 ).
Laachachi et al. Polymer
Degradation and Stability 89 (2005)
344e352 [15]

67. • Hamming et al. studied the quality of dispersion and interfacial interaction
between TiO2 nanoparticles and host polymer, along with the effect on glass
transition temperature (Tg), observed that bulk properties of nanocomposites
are highly sensitive to both the quality of the interfacial interaction and
quality of dispersion of the nanoparticles and that these factors must be
controlled to create the nanocomposites with specific and predictable
behavior.
Average value of Tg for each type of composite measured by
DSC. From left to right: 2wt% modified TiO2 in PMMA, PMMA
control, 0.5wt% TiO2 in PMMA, 2wt% TiO2 in PMMA,
3wt% TiO2 in PMMA, 10wt% TiO2 in PMMA, 20wt% TiO2 in
PMMA.
Hamming et al.2009,
Compos Sci Technology, 69,
1880-1886 [16]

68. APPLICATION
S.No Polymer-metal oxide composite Applications
1 Polycaprolactone/SiO2 For skeletal tissue repair.
2 Polyimide/SiO2 Microelectronics
3 PMMA/SiO2 Dental application, optical
devices
4 Polyethylacrylate/SiO2 Catalysis support, stationary
phase for chromatography
5 Poly (p- phenylene vinylene)/SiO2 Non-liner optical material for
optical waveguides.
6 Poly(amide-imide) / TiO2 Composite membranes for gas
separation applications.
7 Poly(3,4-ethylene-dioxythiophene)/V2
O5
Cathode materials for
rechargeable lithium batteries.

69. APPLICATION IN LITHIUM ION BATTERIES
PTG nanocomposite is a
promising anode material for
highly efficient lithium ion
batteries (LIBs) with fast
charge/discharge rate and
high enhanced cycling
performance [discharge
capacity of 149.8 mAh/g
accompanying Coulombic
efficiency of 99.19% at a
current density of 5C (1000
mA/g) after 100 cycles]
Zhang et al. Inorg. Chem. 2012, 51, 9544−9551 [17]

70. METAL OXIDE NP- CNT NANOCOMPOSITE
• CNT is well-known for its outstanding electrical and mechanical properties
such as high length to diameter ratio (up to 132,000,000:1) and intrinsically
metallic property .
• Its exceptional vertical growth mechanism facilitates the formation of a
continuous network for perfect charge transport along the longitude
direction. This mechanism can also form an excellent three-dimensional
template known as “CNT-forest” for depositing metal-oxide to improve the
energy storage capability.
• Carbon nanotube-forest (CNT-F) template has been coupled with MnO2,
NiO, Co3O4.
• CNT is not soluble in water, we can increase its solubility by combining it
with metal oxide nanoparticles.

71. SYNTHESIS METHODS
• Synthesis of CNT-Metal oxide nanoparticles is based on two
approaches:
1. The dispersion of CNTs in a metallic precursor solution followed by a
chemical synthesis step (i.e., hydrothermal, microwave synthesis, or
ultrasonication.
2. The functionalization of CNT sidewalls with organic ligands followed
by the physical or chemical attachment of nanoparticles.
• Both method types, use dispersed CNTs and lead to bulk composite
materials that incorporate randomly oriented CNTs among an inorganic
matrix. Such structures render a poor connection between the CNTs and
the matrix which ultimately affects the hybrid properties. So, this
approach is not suitable for fabricating 3D nanostructures.

72. Schematic representation of the experimental steps showing the fabrication of
3D mesoporous hybrid CNT/oxide architectures and 3D mesoporous metal
oxide structures. (Mazloumi et al. ACS Nano, 2013, Vol 7,4281-4288.)[18]

73. MICROEMULSION PROCESS
Synthetic scheme for
surface coverage of
metal oxide
nanoparticles onto
MWNTs using water-in-
oil microemulsions.[19]
CNTs + NaDDBS (sodium dodecylbenezenesulfonate) (in water) + Triton X (in
cyclohexane)
this mixture + metal ion (metal acetate + LiOH) 40 °C / 2 hr stirring Calcination
Sun et al. Chemical
Communications 7
(2004): 832-833.

74. • Illustration of the fabrication process of a TiO2. -CNT-Si solar cell involving the following steps:
1. Creating a cell device window by transferring a CNT film on a Si wafer (with 400 nm oxide)
and applying Ag paste around the film,
2. etching away the oxide layer to form direct CNT-Si contact and junction,
3. spin-coating a thin TiO2. colloid on top of the CNT film as antireflection layer,
4. chemical doping of the cell by vapor of HNO3. and H2O2.
Shi et al. Scientific Reports, Nov 2002, [20]
Application in solar cell

75. APPLICATION IN HYDROGEN STORAGE
Silambarasan et al. ACS applied materials & interfaces 5.21 (2013): 11419-11426[21]

76. APPLICATIONS
1. Application in environment - can be used as adsorbents, photocatalyst,
sensor to tackle pollution problems. Metal oxide nps are used in combination
with graphene, silica, CNT , polymers for removal of dye, metals such as Hg
2. Application in agriculture and food - Widely used is packaging foodstuff,
increase shelf life of products, TiO2 nps are commonly used, also used as
antibacterial agent (Silver oxide nanocomposites) . In agriculture sector,
metal oxide nps (ZnO, CeO, CuO) and their nanocomposite with fertilizer
and zeolite are used as slow and controlled release of fertilizers to provide
plant nutrition, also helps to prevent soil degradation
3. Application in health and medicine - drug delivery, detection and
screening of diseases, DNA sequencing, gene therapy, tissue culturing.
4. Coating - TiO2 -based organic coatings and reported that the TiO2
nanoparticles have advantages such as good stability, high refractive index,
hydrophilicity, ultraviolet (UV) resistance and excellent transparency for the
visible light, nontoxicity, high photocatalytic activity, and low cost.

77. REFERENCES
1. Sun Feng Yu, Liu Bo Shao Meng Li- Fan, Liu Yun-Jin, Jin Zhen, Kong Tao Ling and
Liu Huai- Jin “Metal oxide Nanostructures and their sensing properties: A Review”,
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2. Hameed, Abdulrahman Syedahamed Haja, et al. "Impact of alkaline metal ions Mg2+,
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4. Kumar, Ajeet, et al. "Facile synthesis of size-tunable copper and copper oxide
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6. Fernández‐García, Marcos, and José A. Rodriguez. "Metal oxide
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Nanocomposites." Organic-Inorganic Hybrid Nanomaterials. Springer International
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8. Hong, J. I., et al. "Rescaled electrical properties of ZnO/low density polyethylene
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78. 9. Chae, Dong Wook, and Byoung Chul Kim. "Characterization on polystyrene/zinc oxide
nanocomposites prepared from solution mixing." Polymers for advanced
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10. Lü, Changli, and Bai Yang. "High refractive index organic–inorganic nanocomposites:
design, synthesis and application." Journal of Materials Chemistry 19.19 (2009): 2884-
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11. Wu, Yanfei, et al. "One-step preparation of PS/ TiO2 nanocomposite particles via
miniemulsion polymerization." Journal of colloid and interface science 343.1 (2010): 18-
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12. Hanemann, Thomas, and Dorothée Vinga Szabó. "Polymer-nanoparticle composites: from
synthesis to modern applications." Materials 3.6 (2010): 3468-3517.
13. Xiong, M.; Zhou, S.; Wu, L.; Wang, B.; Yang, L. Sol-gel derived organic-inorganic hybrid
from trialkoxysilane -capped acrylic resin and titania: effects of preparation conditions on
the structureand properties. Polymer 2004, 45, 8127-8138.
14. Jeziórska, Regina, et al. "Structure and mechanical properties of low‐density
polyethylene/spherical silica nanocomposites prepared by melt mixing: The joint action
of silica's size, functionality, and compatibilizer." Journal of Applied Polymer
Science 125.6 (2012): 4326-4337.
15. Laachachi, A., et al. "Influence of TiO 2 and Fe 2 O 3 fillers on the thermal properties of
poly (methyl methacrylate)(PMMA)." Materials Letters 59.1 (2005): 36-39.
16. Hamming, Lesley M., et al. "Effects of dispersion and interfacial modification on the
macroscale properties of TiO2 polymer–matrix nanocomposites." Composites science
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79. 17. . Zhang, Fan, et al. "Enhanced anode performances of polyaniline–TiO2–reduced
graphene oxide nanocomposites for lithium ion batteries." Inorganic chemistry 51.17
(2012): 9544-9551.
18. Mazloumi, Mahyar, et al. "Fabrication of three-dimensional carbon nanotube and metal
oxide hybrid mesoporous architectures." Acs Nano 7.5 (2013): 4281-4288.
19. Sun, Jing, Lian Gao, and Mikio Iwasa. "Non covalent attachment of oxide nanoparticles
onto carbon nanotubes using water-in-oil microemulsions." Chemical Communications 7
(2004): 832-833.
20. Shi, Enzheng, et al. " TiO2 -coated carbon nanotube-silicon solar cells with efficiency of
15%." Scientific reports 2 (2012).
21. Silambarasan, D., et al. "Single Walled Carbon Nanotube–Metal Oxide Nanocomposites
for Reversible and Reproducible Storage of Hydrogen." ACS applied materials &
interfaces 5.21 (2013): 11419-11426.

80. MAGNETIC NANOPARTICLES

81. CONTENTS
• Magnetic Nanoparticles
• Types of magnetic nanoparticles
 Magnetic iron oxide nanoparticles
• Types of magnetic nanocomposites
 Core–shell inorganic nanocomposites
 Self-assembled nanocomposites
 Organic–inorganic nanocomposites
• Magnetic- polymer nanocomposites
 Synthesis methods
 Applications

82. MAGNETIC NANOPARTICLES
• Magnetic nanoparticles are nanoparticles type which can easily be tracked,
manipulated and targeted using external magnetic field.
• When magnetic field is applied to nanoparticle, a dipole is induced, when
no field is applied nanoparticles return to original non-magnetic state.
• These are composed of elements iron, cobalt, nickel and their oxides.
• Iron oxide nanoparticles are common magnetic nanoparticles used due to
high electrical resistivity, chemical stability, mechanical hardness, magnetic
properties in radiofrequency region.
• Magnetic nanoparticles are useful for catalysis, magnetic fluids, data storage,
biomedicine, magnetic resonance imaging (MRI), environmental remediation.

83. TYPES OF MAGNETIC NANOPARTICLES
1. Metal and metal oxide nanoparticles- Include transition metals Fe, Co,
Ni, show ferromagnetism at low temperature and paramagnetism at high
temperature. Oxides of these metals also show magnetic behavior, Iron
oxide commonly used.
2. Ferrites- Ferrites belong to nonconductive class of ferromagnetic
materials derived from metal oxides as α-Fe2O3, magnetite (Fe3O4).
Ferrites have three different structural symmetries: garnet, hexagonal, and
cubic or spinel ferrites which are determined by the size and charge of the
metal ions that balance the charge of the oxygen ions and their relative
amounts.
3. Dilute metal semiconductors- These possess characteristics of both
semiconductors as well as magnetic properties. In DMS, a fraction of the
cations in the lattice are substituted by magnetic ions, and atomic spin on
these magnetic ions interacts with the carriers in the lattice to bring
ferromagnetic order in the material. Thus, these materials have unusual
magnetic characteristics due to the presence of isolated magnetic ions in
semiconducting lattice. The DMS includes simple oxides like SnO2 ,
ZnO, TiO2 , or mixed oxides doped with several transition metals (Fe, Co,
Ni, Mn) or rare earth metals (Dy, Eu, Er).

84. 4. Polymer magnets
• A polymer magnet or plastic magnet is a nonmetallic magnet made from an
organic polymer.
• Torrance et al. synthesized poly(1,3,5-triaminobenzene) which when
oxidized with iodine was reported to show a ferromagnetic phase up to
400 °C. [3]
• In 2004, Zaidi et al. reported the synthesis of a novel magnetic polymer
PANiCNQ produced from polyaniline (PANi) and an acceptor molecule,
tetracyanoquinodimethane (TCNQ), the first magnetic polymer to function
at room temperature.
• PANiCNQ combines a fully conjugated nitrogen containing backbone with
molecular charge transfer side groups, and this combination gives rise to a
stable polymer with a high density of localized spins which are expected to
give rise to coupling. Magnetic measurements suggest that the polymer is
ferrimagnetic with a curie temperature of over 350 K and a maximum
saturation magnetization of 0.1 JT−1 kg−1. [4]

85. MAGNETIC IRON OXIDE
NANOPARTICLES
1. Co-precipitation
I. Widely used method for synthesis of oxide nanoparticles.
II. Addition of base (NaOH, NH4OH) to Fe2+/Fe3+ solution at room
temperature or elevated temperature.
III. Size and shape can be controlled by
• Variation of different salts such as chlorides, sulphates and nitrates
• Variation in Fe2+/Fe3+ ratio
• Temperature and pH variation (Eg: Precipitation at 60οC produces
Fe2O3 nps, precipitation at 80οC produces Fe3O4 nps)
• Ionic strength of media
Advantages Disadvantages
Low reaction temperature Insufficient size control distribution
Short reaction time Uncontrolled shape

86. 2. Microemulsion method – surfactant used for iron oxide nanoparticle
is sodium dioctylfosuccinate (Aerosol OT or AOT)
3. Solvothermal, hydrothermal method –
• The process takes place in autoclave and reactor under high
temperature and pressure.
• Low reaction temperature, low reaction time and low cost are
characteristic of this method.
• Can be used in combination with microwave, sol-gel processes that
help in formation of single phased material with higher stability.
4. Chemical vapor deposition -
• Synthesis of iron oxide by reaction of FeCl3 with water at 1000οC
• Low yield, existence of complex phase and difficulty in seperating iron
oxide nanoparticles from impurities.
• Thermal CVD and MOCVD can also be used for preparation of iron
oxide nanoparticles.

87. APPLICATIONS
• Fe3O4 or Magnetite nps used in numerous application due to
a) Chemical stability
b) Biocompatibility
c) Low toxicity
d) Small size, large surface area
e) Superparamagnetic property and easy manipulation under applied field
allows nps to be reused or recycled.
• Drug delivery - can be used for targetted drug delivery,
• Magnetic resonance tomography (MRT) –
• permits non invasive visualization of cross sectional images of human
body, where magnetic nanoparticles are used as contrast agents.
• Magnetite can differentiate between healthy and malignant liver cells.
• Functionalization with ligands can improve their use.
• Can also be used for removal of metals Hg, Cu, Co, Cr, Pb from water and
also used for hard disk drives.

88. TYPES OF MAGNETIC NANOCOMPOSITES
1. Core–shell inorganic nanocomposites
2. Self-assembled nanocomposites
3. Organic–inorganic nanocomposites

89. CORE-SHELL INORGANIC NANOCOMPOSITES
• Hybrid NPs provide a platform with dual imaging capabilities for medical
diagnosis (e.g., simultaneous magnetic and optical imaging), combines
magnetic imaging and therapy, and multiplexing in sensors.
• The general strategy for core-shell nanostructures is to first prepare NPs of
one material, and then use them as nucleation seeds to deposit the other
material.
• One of the simplest methods for preparing core–shell type NPs has been the
partial oxidation of magnetic metal NPs to form a shell of the native oxide on
the particle surface. Polycrystalline Fe3O4 shells, e.g., which were generated
by chemical oxidation on Fe particles, were shown to successfully protect and
stabilize Fe NPs against full oxidation. [8]
• Bimagnetic core–shell systems such as FePt-Fe3O4 or FePt-CoFe2O4, where
both core and shell are strongly magnetic (ferro- or ferrimagnetic), show
effective exchange coupling phenomena and facilitate the fabrication of
magnetic materials with tunable properties. Bimagnetic FePt/MFe2O4 (M=Fe,
Co) core/shell nanoparticles are synthesized via high-temperature solution
phase coating of 3.5 nm FePt core with MFe2O4 shell. [9]

90. SELF ASSEMBLED NANOCOMPOSITES
• The self-assembly of small building blocks (e.g., atoms, molecules,
and nanoparticles) into ordered macroscopic superstructures has
been an important issue in various areas of chemistry, biology, and
material science.
• Self-assembly of NPs into 2D and 3D superlattices with a high
degree of translational order has attracted a lot of attention .
• Bergström and coworkers self-assembled super crystals of iron
oxide nanocubes by a drying-mediated process, applying a magnetic field at
the initial stage of the process. These super crystals had both translational as
well as orientational order with crystallographic alignment of the nanocubes
[10]

91. ORGANIC- INORGANIC NANOCOMPOSITES
• This is the classical type of a nanocomposite, where the isolated NPs are
finely dispersed in a polymer. i.e. agglomerated NPs are dispersed in a
polymer matrix.
• Functional nanocomposites with improved physical properties allow various
applications (e.g., in biomedical, micro-optics, electronics, energy
conversion, or storage).
• In most of the cases, the change of the aspired feature correlates with the
filler load. The resulting composite flow behavior limits mostly huge solid
loadings and therefore property adjustment due to restrictions in shaping or
molding. Shear rate and temperature-dependent as well as oscillatory
rheological investigations are therefore necessary for a detailed description
of the composite flow properties prior to shape forming .
• In case of nanosized fillers, the specific surface area and the resulting huge
polymer-filler interfacial layer dominates the rheological behavior.

92. MAGNETIC NPS - POLYMER NANOCOMPOSITE
• Magnetic polymer nanocomposites can be defined as materials
composed of an inorganic magnetic component in the form of particles,
fibers or lamellae with at least one dimension in the nanometer range
(1±100 nm) embedded in an organic polymer or vice versa.
• The polymer can play several roles in magnetic nanocomposites:
 As a template to control size, shape and organization
 As a coating protecting from the environment, an isolator, a separator or
a compacting medium
 Endowing the magnetic material with the mechanical properties and
processability of the polymers
 As a functional component, adding its own optical, electrical or
chemical
properties, enhancing the properties of the magnetic component, or
creating new properties by interaction with the magnetic component.

93. TYPES OF MAGNETIC POLYMER NCS

94. SYNTHESIS METHODS
1. Separated precipitation of the magnetic component and polymerization, and
then mixing of the magnetic nanoparticles and the polymer.
 Large aggregates of nanocomposite formed and the polymer is not soluble
in a common solvent.
2. Precipitation of the magnetic component, mixing the magnetic nanoparticles
with the monomer, and then in-situ polymerization.
 Homogenous nanocomposites formed but still difficulty in controlling size
and solubilization of polymer is also a problem.
3. Polymerization, mixing of the precursor with the polymer, and then in-situ
precipitation.
 Most common synthesis route for producing homogenous nanocomposites
with controllable size.
4. Mixing monomer and precursor, and then simultaneous precipitation and
polymerization.
 Not used much due to poor control over the polymer and the nanoparticles.

96. MIXING OR BLENDING PRE-SYNTHESIZED
CONDUCTING POLYMERS AND MAGNETIC NPS
• Hybrid nanoparticles–polymer nanocomposites are typically prepared by blending or
mixing the different components in solution or in a melting process.
• Not feasible strategy for conjugated polymers as they are insoluble in common
solvent and present high melting temperature.
• Less examples of this approach as the polymer has to be soluble or dispersible in the
solvent and also the magnetic nanoparticles need to be colloidal stable in order to
avoid the aggregation in the final nanocomposite.
• Polymers such as poly(1-vinyl-1,2,4-triazole) , as well as a polypyrrole derivative,
poly (N- pyrrole phosphonic acid) , were mixed with Fe3O4 nanoparticles in aqueous
solution leading conducting and magnetic nanocomposites.
• PEDOT:PSS (polystyrene sulfonate) system was mixed with anionic iron oxide
nanoparticles to obtain nanocomposite.
• Layer by layer technique recently used to prepare several nanocomposite thin films
from conducting polymer solution and ferrofluids for different applications . In these
approaches layers of positively charged conducting polymer, such as PPy and
poly(o-ethoxyaniline), in combination with positively charged magnetic
nanoparticles were deposited alternatively with layers of negatively charged
polymers such as polystyrene sulfonate.

97. IN SITU SYNTHESIS OF MAGNETIC NANOPARTICLES
INTO CONDUCTING POLYMERS
• Magnetite nanoparticles were synthesized by coprecipitation method in an
aqueous solution containing a pre-synthesized poly (3-pyrrol-1-ylpropanoic acid)
• The incorporation of sulfonated groups into polyaniline allows the preparation of
the nanocomposites in aqueous solution by the in situ synthesis of iron oxide
nanoparticles in the polymer solution.
• Polymer chains can be chemically attached to the surface of the nanoparticles to
enhance the final properties of the nanocomposites. These polymers with
sulfonated groups, such as poly(pyrrole-N- propylsulfonate), are prepared by
reaction with FeCl3 to produce polymers with pendant SO3
− and Fe2+ ions that
provide overall charge neutrality in the material . Further treatment with NH4OH
allows the synthesis of iron oxide nanoparticles in the polymer solution.[11]

98. IN SITU POLYMERIZATION IN THE PRESENCE OF
MAGNETIC NANOPARTICLES
• It is used to prepare nanocomposites based on conducting polymers.
• Polymerization can be carried out in either homogeneous medium or
heterogeneous medium, i.e., in emulsion using surfactants, providing different
types of nanocomposites, from films to core–shell particles.
• The easiest strategy consists the in situ polymerization of monomers, such as
pyrrole or aniline, in solution and in the presence of magnetic nanoparticles.
• In this approach the selection of the solvent is of great importance to obtain a
proper nanocomposite with the nanoparticles well dispersed into the polymeric
matrix.
• The solvent should dissolve the monomer and the magnetic nanoparticles have
to be colloidally stable in it to avoid their agglomeration.
• Vigorous stirring of the solution and/or sonication are normally required to
suspend the nanoparticles and prevent their aggregation during the
polymerization. Once the polymer is formed, thus the nanocomposite, a black
precipitate is normally obtained in the reaction medium.

99. • Polyaniline is usually prepared by oxidative polymerization of aniline in acidic
aqueous solution using oxidants such as ammonium persulfate. Under those
conditions a wide number of magnetic nanocomposites based on PANI have
been prepared by incorporation of magnetic nanoparticles such as Fe3O4 ,
NiFe2O4 , CoFe2O4 , and ZnFe2O4 into the polymerization mixture.
• Microemulsion methods are also used in which surfactants such as SDS (sodium
dodecyl sulfate), DABS (dodecyl benzene sulphonic acid), CTAB
(cetyltrimethylammonium bromide) stabilize the magnetic nanoparticles. Then,
the monomer molecules are adsorbed at the surface of the magnetic
nanoparticles and the polymerization takes place to generate core–shell
structures
Schematic representation of the formation of particle nanocomposites
via in situ oxidative emulsion polymerization

100. SIMULTANEOUS POLYMERIZATION AND
SYNTHESIS OF MAGNETIC NANOPARTICLES
• In this methodology the synthesis of the nanoparticles and the
monomer polymerization is carried out simultaneously in order
to produce a homogenous nanocomposite.
• PANI/Fe3O4 nanocomposites have been obtained in one single
step in aqueous solution as common solvent. Typically, aniline
monomer is added to a mixed solution of FeCl2 and FeCl3,
which works as oxidant. The pH is controlled with NH3 and
after a certain time a black precipitate of PANI/Fe3O4 is
formed.[12]
• Poly(p- phenylenediamine) (PpPD)/Fe3O4 composites were
prepared by chemical oxidation polymerization of pPD
monomer with APS and Fe(NO3)3 as oxidizing agents. The
Fe3+ was partly reduced to Fe2+ allowing the formation of the
magnetite nanoparticles.[13]

101. APPLICATIONS
1. Electromagnetic shielding and Microwave absorbing materials
• Reduce interference induced by electronic signals in electronic device.
• Shielding material can be placed to increase light absorption.
• A core shell nanocomposite of barium ferrite and PEDOT (poly- (3,4
ethylenedioxythiophene)) by in-situ polymerization could be used as
electromagnetic shielding material, where barium ferrite has high resistivity,
while PEDOT provides conductivity and dielectric properties. Strong
absorption in 12-18 GHz.
Schematic representation
of EMI shielding

102. 2. Polymer solar cells
• Bulk heterojunction solar cell (BHJ) could be substituted for
inorganic solar cells due to ease of fabrication, flexibility, low cost
and large scale production.
(a) Schematic illustration of the fabrication procedure of a solution-processed Fe3O4
NP, followed by external magnetostatic field alignment, as a HEL for PSCs and (b) the
LUMO and HOMO energy levels of P3HT (poly(3-hexylthiophene-2,5-diyl) ) and PCBM
([6,6]-phenyl-C61-butyricacidmethyl ester )and work functions of PEDOT:PSS
(poly(3,4-ethylenedioxythiophene) polystyrene sulfonate), Fe3O4, ITO, and Ca (Al)
Zang, Kai et al. ACS applied materials & interfaces 5.20 (2013): 10325-10330.[14]

103. 3. Sensors
• Immobilization of magnetic nanoparticles on the surface of magnetic glassy
carbon electrode (MGCE) is considered very promising approach for fabrication of
biosensors due to its high specific surface area and stability.
• Polypyyrole - ZnFe2O4 on MCGE for enzymeless glucose sensor, Biosensor based
on Fe2O3 -Polypyyrole by immobilization of biotin was also prepared.
• Bilirubin, a common metabolite of hemoglobin, is normally conjugated with albumin to
form a water-soluble complex and excreted from hepatocytes into bile mainly as bilirubin
glucuronides. Serum bilirubin is helpful in detection of liver diseases.
Schematic for (a) fabrication and (b) detection mechanism of the photoelectrochemical bilirubin
biosensor
Yang, Zheng peng, et al. Sensors and Actuators B: Chemical 201 (2014): 167-172.[15]

104. REFERENCES
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2. Kalia, Susheel, et al. "Magnetic polymer nanocomposites for environmental and biomedical
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105. 11. Wan M, Fan J (1998) Synthesis and ferromagnetic properties of composites of a water-
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applied materials & interfaces 5.20 (2013): 10325-10330.
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106. Thank You