title: Sol-gel network silica/modified montmorillonite clay hybrid nanocomposites for hydrophobic surface coatings.
abstract: Sol-gel silica/nanoclay composites were prepared through sol-gel polymerization technique using tetraethylorthosilicate precursor and montmorillonite (MMT) clay in aqueous media. In this study, both montmorillonite-K(+) and organically modified MMT (OMMT) clays were used. The prepared composites were coated on glass substrate by making 1 wt% solution in ethyltrichlorosilane. The incorporation of nanoclay does not alter the intensity of characteristic Si-O-Si peak of silica network. Thermogravimetric studies show that increasing clay content increased the degradation temperature of the composites. Differential scanning calorimetry (DSC) results of organically modified MMT nanoclay incorporated composite show a shift in the melting behavior up to 38°C. From DSC thermograms, we observed that the ΔH value decreased with increasing clay loading. X-ray diffraction patterns prove the presence of nanoclay in the composite and increase in the concentration of organically modified nanoclay from 3 to 5 wt% increases the intensity of the peak at 2θ=8° corresponds to OMMT. Morphology of the control silica gel composite was greatly influenced by the incorporation of OMMT. The presence of nanoclay changed the surface of control silica gel composite into cleaved surface with brittle in nature. Contact angle measurements were done for the coatings to study their surface behavior. These hybrid coatings on glass substrate may have applications for hydrophobic coatings on leather substrate.
authors: Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Polymer Division, Adyar, Chennai, India.
authors: Kamal Mohamed Seeni
authors: KM
authors: Meera
authors: Rajavelu Murali
authors: RM
authors: Sankar
authors: Adhigan
authors: A
authors: Murali
authors: Sellamuthu N
authors: SN
authors: Jaisankar
authors: Asit Baran
authors: AB
authors: Mandal
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D000077215:Clay; D005898:Glass / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D044367:Phase Transition; D058105:Polymerization; D012821:Silanes / Q000737:chemistry; D058428:Silica Gel / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D012821:Silanes; D001546:Bentonite; D058428:Silica Gel; D000077215:Clay