The preparation of surfactant-templated periodic mesoporous silica thin films functionalized with N-((trimethoxysilyl)propyl)-N,N,N-trimethylammonium chloride (TMAC) is described. The supramolecular self-assembly of the triblock copolymer, Pluronic 123, served as a template for the formation of these functionalized silane films. In the as-prepared and extracted conditions, the films exhibited the p6 mm type hexagonal mesostructure with a large unit cell (a = 8.5-9.6 nm). Contraction of the films during heat treatment (250 degreesC for 2 h) reduced the pore spacing perpendicular to the substrate yielding Fm3m pore ordering, confirmed by X-ray diffraction and transmission electron microscopy. Ellipsometry measurements revealed the films to have thickness of similar to400 nm in the as-prepared condition and similar to300 nm in the heat-treated condition, a total shrinkage of similar to25% perpendicular to the substrate. X-ray photoelectron spectroscopy measurements showed the incorporation of the TMAC to be 76-90% of the amount initially added followed surfactant extraction.