Design, synthesis, and properties of inorganic and hybrid thin films having periodically organized nanoporosity

This review presents an extensive discussion on the major advances in the field of periodically organized mesoporous thin films (POMTFs) obtained via surfactant templated growth of inorganic or hybrid polymers. A large variety of templating agents can be coupled with inorganic polymerization reactions for the design of periodically organized nanostructured hybrid phases that yield POMTFs. The tuning of the interface between the template and the polymerizing phase and the control over chemical and processing conditions are the key parameters in producing tailor-made POMTFs with a high degree of reproducibility. This dynamic coupling between chemical and processing conditions dictates extensive use of complementary ex situ measurements with in situ characterization techniques that follow, in real time, film formation from the molecular precursor solutions to the final stabilized POMTF. Among modern analytical tools, 2D-GISAXS, ellipsoporosimetry, HRTEM, X-ray reflectometry, WAXS, time-resolved infrared spectroscopy, SAW, and optically polarized xenon NMR have proved to be highly relevant for this purpose. POMTFs combine the intrinsic physical and chemical properties of the inorganic or hybrid matrices with a highly defined nanoporous network having a tunable pore size and connectivity, high surface area and accessibility, and a specific orientation with respect to the substrate. As such, POMTFs are a promising family of advanced materials for a host of future applications including micro-optics and photonic devices, microelectronics, nanoionics and energy, environment, functional and protective coatings, biomaterials, environmentally responsive materials, and biomicrofluidics, among others.