Coatings were prepared from suspensions containing colloidal silica (20 nm) in isopropanol and 3-glycidoxypropyltrimethoxysilane (GPS). Thicker coatings without cracks were achieved by increased addition of GPS. The microstructure of the resultant coatings contained well packed colloids with some pore space. When high amounts of GPS were added (i.e., GPS:silica weight ratio (R) greater than 0.5), polymeric material appeared and covered the necks between particles and filled in pores. 29Si NMR of coating suspensions (R = 1) showed GPS hydrolysis within a few minutes and GPS adsorption on the silica surface within a few hours. The excess silane remained in solution and further polymerized, instead of forming a thick multilayer on the colloids. Diffuse reflectance IR spectroscopy data suggests saturated surface coverage beginning around 2 to 3 molecules/nm2 based on observed depletion of silica surface hydroxyls.
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - Dec 1 1996|
|Event||Proceedings of the 1996 MRS Spring Symposium - San Francisco, CA, USA|
Duration: Apr 8 1996 → Apr 12 1996