THIN MOLECULAR-SIEVE FILMS ON NOBLE-METAL SUBSTRATES

A novel method whereby dense thin microporous films less than 300 nm t hick may be prepared on noble metal substrates is exemplified by the d eposition of silicalite-l on a gold surface in a three-step process. T he gold surface is modified with a silane coupling agent, gamma-mercap topropyltrimethoxysilane, after which the silane is hydrolyzed to yiel d a negatively charged interface. Positively charged colloidal silical ite-l crystals are readily adsorbed as a monolayer upon this surface a nd are induced to crystallize further in a separate hydrothermal treat ment step to yield a dense thin silicalite-l film. (C) Elsevier Scienc e Inc. 1997.