Pure and molecularly mixed inorganic films for protection against atomic oxygen in lower earth orbit were prepared using radio-frequency (rf) plasma magnetron sputtering technique. Alumina (Al2O3) and silica (SiO2) films with average grain size in the range of 30-80 nm and fully,dense or dense columnar structure were synthesized under different conditions of pressure and power. Simultaneous oxide sputtering and plasma polymerization (PP) of hexafluoropropylene (HFP) led to the formation of molecularly mixed films with fluoropolymer content. The degree of plasma polymerization was strongly influenced by total chamber pressure and the argon to HFP molar ratio (n(Ar)/n(M)). An order of magnitude increase in pressure due to argon during codeposition changed the plasma-polymerization mechanism from radical-chain- to radical-radical-type processes. Subsequently, a shift from linear CH2 group based chain polymerization to highly disordered fluoropolymer content with branching and cross-linking was observed. Fourier transform infrared spectroscopy studies revealed chemical interaction between depositing SiO2 and PP-HFP through appearance of absorption bands characteristic of Si-F stretching and expansion of SiO2 network. The relative amount and composition of plasma-polymerized fluoropolymer in such films can be controlled by changing argon to HFP flow ratio, total chamber pressure, and applied power. These films offer great potential for use as protective coatings in aerospace applications. 0 2008 American Vacuum Society.