PREPARATION AND CHARACTERIZATION OF ULTRAFINE SILICA

Silica dispersions of size ranging from 20-60 nm with solid content ra nging from 1-2 wt.% were prepared by hydrolysis followed by condensati on of TEOS in methanol. Aqueous dispersions were prepared by adding ap propriate amounts of water to the dispersion and removing the methanol by vacuum distillation in a rotary evaporator. The solid contents of the aqueous dispersions varied between 5 and 7 wt.%. These dispersions were produced for use as model colloids in thin-film coating experime nts. The dispersions were characterized by dynamic light scattering, g el permeation chromatography and zeta potential measurements. (C) 1998 Elsevier Science B.V.