STUDY OF PENETRATION OF WATER INTO HYDROPHOBIZED POROUS SILICAS

Intrusion of water into a pore space of silicas hydrophobized with alk ylsilanes is studied. The water porosimetry technique is introduced an d construction of a water porosimeter is described. The effects of bon ded alkyl chain length, bonding density, structure of alkylsilane, and average pore diameter of silica on the parameters of water intrusion are studied. Advancing and receding angles of water on chemically modi fied silica surfaces are estimated. It is shown that contact angles in crease as bonding density and bonded chain length are increased. The c orrelation between the structure of a bonded alkylsilane monolayer and its hydrophobicity is discussed. (C) 1997 Academic Press.