Preparation and some properties of organically modified layered alkali titanates with alkylmethoxysilanes

The silylation of K₂Ti₄O₉·nH ₂O with organosilanes (methyl, n-butyl, n-octyl, n-dodecyl, n-octadecyltrimethoxysilanes and n-octadecyldimethylmethoxysilane) was conducted using the octylammonium-exchanged form as the intermediate. The surface coverage of the octadecylsilylated derivative was controlled by changing the employing amounts of octadecyltrimethoxysilane. The swelling behaviors of the octyl, dodecyl, and octadecylsilylated derivatives in organic solvents were investigated to show that the degree of the swelling varies depending on the kind of solvents, the alkyl chain length of the attached alkylsilyl groups, and the surface coverage. The octadecylsilylated derivative with the largest surface coverage was converted to film with a thickness of ca. 500 nm by casting the chloroform suspension on a substrate. The octadecylsilylated derivative showed a reversible thermoresponsive change of the basal spacing by ca. 0.5 nm in the temperature range between 15 and 60°C.