CARBON COATING OF SILICA SURFACE .1. PYROLYSIS OF SILICA-GELS ESTERIFIED WITH ALCOHOLS

A silica gel was esterified with alcohols and reacted with carbon tetrachloride to cross-link the RO-(R, alkyl or arylalkyl) groups on the silica surface. These esterified and cross-linked silica gels were subsequently pyrolyzed under vacuum to yield carbon-coated silica gels (CSG). The surface properties and pore structure of the CSG were compared with those of CSG prepared by a conventional chemical vapor deposition method. It was found that the new method remarkably improved the extent of carbon coating of the silica surface. The carbon film was formed uniformly on both the inner and the outer surfaces of the silica gel; the thickness of the carbon files was about 1 nm. No blockage of the pores of the silica gel was observed when this method was used. © 1993 Academic Press, Inc.