We describe a synthetic method for the formation of surfactant-templat
ed periodic mesoporous silica thin films. The films, when deposited be
tween 0.22 < t/t(gel) < 0.67, are crack-free, consist of aggregated su
bmicrometer particles, each of which contains the familiar honeycomb a
rrangement of 30-44 Angstrom diameter channels, and have specific surf
ace areas greater than 400 m(2)/g. The synthetic method, which we call
gas-catalyzed thin film synthesis (GCTFS), involves diffusing ammonia
into a homogeneous micellar coating solution on a nonporous substrate
. This method ameliorates the problems associated with coating substra
tes from inhomogeneous solutions. We have studied and optimized GCTFS
with light scattering, Si-29 NMR, XRD, optical microscopy, SEM, TEM, a
nd isothermal N-2 sorption measurements.