The document discusses surface modification of nanoparticles to improve their properties and applications. Surface modification can make nanoparticles more hydrophilic, hydrophobic, conductive or anticorrosive. Functionalizing nanoparticle surfaces is necessary to optimize properties for use in various fields like engineering, medicine and biology. Common modification techniques discussed are NMR, FTIR, RAMAN spectroscopy, and TEM imaging. Surface modification can improve nanoparticle dispersion, enhance coatings for scratch/corrosion resistance, and develop transparent, wear resistant or superhydrophobic coatings.
2. There are limitations in the applications of
nanomaterials because of their restricted
behaviour in different solvents
Surface modifications of nanomaterials help to
tune their properties to suit different applications
in the field of nanotechnology, because surface
properties determine the interaction among the
components, as well as the solubility and
agglomeration behaviour in different solvents
3. Chemical modification of nanoparticle surface
Main aim is to make nanomaterial;
To gain Hydrophilic, hydrophobic, conductive or anticorrosive properties
4. Development of multi-functional hybrid coating for scratch and
corrosion resistance: inorganic (nanoparticle) and organic component
(active site)
• Functionalized nanoparticles can be applied in different areas:
engineering, medical, biological, etc.
Its necessary optimize the active sites on the nanoparticle surface
(hydrophilic, hydrophobic, conductive etc)
5.
6.
7. • NMR (Nuclear Magnetic Resonance) spectroscopy 1H and 13C;
• FTIR (Fourier Transform Infrared in the transmission mode at
400 – 4000 cm-1 – degree of modification of the nanoparticles;
• RAMAN SPECTROSCOPY
• TEM (Transmission Electron Microscopy) images – effect of
modification of nanoparticles on their dispersion properties;
• EIS (Electrochemical Impedance Spectroscopy) – estimate the
corrosion protection performance of the prepared coatings
8. FTIR VIBRATION SURFACE TRANSMISSION ELECTRON
CHARACTERIZATION MICROSCOPY
Aggegation size
• Relatively dispersed at the scale of
100 – 170 nm
A – aminopropyl trimethoxy silane (APS)
B – untreated ZrO2 nanoparticles •Some aggregates particles can be
C – APS – treated ZrO2 nanoparticles observed (-OH: hydrogen bonding)
9. Development of nanotechnology-based organic coating to enhance
anticorrosion properties (incorporation of nanoparticles)
• The improvement in the properties of the nanocoatings is attributed
to their nanoparticles functionalized ;
• Nanomaterials mostly used in coating system: SiO2, TiO2, ZnO,
Al2O3, Fe2O3, nano-aluminum, nano-titanium
10. Improvement of UV-Blocking Coatings
•Inorganic nanoparticles, as alternative to UV-blockers in coating applications
•Nano-ZnO, nano-TiO2, nano-CeO2 : excellent photo- and thermal stability
•Example: transparent ZnO/epoxy nanocomposite coating via in situ
polymerization. Optical properties of the nanocomposite coating depends on
ZnO particle size
11. Development of transparency and wear resistance
•The interface between particle and polymer matrix plays an important role as a
well integrated filler provides better mechanical reinforcement
•When grafted with silanes having a reactive group, particles can be bound
covalently to the polymer matrix via silane surface modification
E. Barna et al, Surface Modification of Nanoparticles for Scratch Resistant Clear Coatings, 2007
14. Improvement of colloidal stability of nanoparticles
•Attractiveness between the grafted polymer and the silica material
In image (a), the silica particles have similar colloidal shape and size, with near-
monodispersed. In image (b), the polymer-grafted silica nanoparticles are further apart.
This indicates that thick layers of hydrophilic methacrylate material were formed
Perruchot, Cat al., Synthesis of Well-Defined, Polymer-Grafted Silica Particles by Aqueous ATRP. Langmuir 2001
15. Fullerene and CNT functionalization
•For improvement of reactivity and adhesion properties
C60 C60(OH)24
Chemically
Phospholipid-coated SWCNT
Fullerene Modified
Fullerene Sayes et al., NanoLet, 2004
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