Preparation of Ultrathin Silsesquioxane Nanofilms via Polymer Langmuir−Blodgett Films

This Article describes a unique approach to building silsesquioxane nanoassemblies based on the Langmuir−Blodgett (LB) technique. Poly(N-dodecylacrylamide-co-3-methacryloxypropyl-T8-heptatrifluoropropyl (or heptaphenylpropyl) POSS)s (p(DDA/SQ)s) were synthesized through free radical copolymerization using propyl methacrylate-substituted polyhedral oligomeric silsesquioxane (POSS) monomers containing seven nonreactive trifluoropropyl or phenyl groups (R7(Si8O12)(CH2CH2CH2OCOCH3C═CH2) (where R is either trifluoropropyl (SQF) or phenyl (SQPh)) and amphiphilic copolymers. The p(DDA/SQ)s formed stable monolayers at the air/water interface. The monolayers were transferred onto solid substrates as Y-type LB films using a vertical dipping method. The polymer LB films had a well-defined layer structure and a surface flatness (rms values < 1 nm in 1 μm2). The high heat-resistant properties of the p(DDA/SQ) LB films were demonstrated using UV−vis spectroscopic reflectometry and FT-IR. The refractive index and the th...