ABSTRACT
The morphology of the surface depends upon the use of solvent during Stöber synthesis. After treating hydrothermally, obtained silica spheres possess smooth surfaces on the use of the surfactant cetyltrimethylammonium bromide (CTAB), whereas corrugated shells are obtained on using isopropanol or butanol. Using static acidic conditions mesoporous spheres of silica whose size lies within the range of 2 to 6 µm have been synthesized. By using cetyl trimethyl ammonium bromide (CTAB) and amphiphilic block copolymer (polystyrene-b-poly(acrylic acid), PS-b-PAA) as the co-templates, dual-mesoporous silica spheres (DMSS) with pore size 2.0 nm can be synthesized. By varying the TEOS amount and length of the hydrophobic block, the size of the pore and the thickness of the shell can 56be tuned. In the case of a heterogeneous system, small particles kept on emerging during the synthesis. By increasing the amount of silica precursor particle size was found to be enlarged. On adding different silica precursor mesoporous sphere of silica having hydrophobic shell and hydrophilic core was obtained. In mesoporous silica spheres, immobilization of enzymes is obtained by layer-by-layer assembly of the thin shells. The use of enzyme provides the enhanced stability of the reaction by increasing the number of layers and reducing the stability of the reaction.
