Deposition of single plasma-polymerized vinyltriethoxysilane films and their layered structure

Plasma polymer films of vinyltriethoxysilane were prepared at the same deposition conditions but different film thicknesses and analyzed with respect to deposition rate, surface morphology and selected mechanical properties. The mean deposition rate decreased from 190 to 105 nm min(-1) and the RMS roughness increased from 0.1 to 17.5 nm with film thickness ranging from 15.8 nm to 8.4 mu m. The RMS roughness correlated to film thickness and the roughening coefficient was 0.92. Depth profiles of the elastic modulus and hardness revealed the gradient character of the films with thickness of up to 0.5 mu m and a layered structure of a thicker film. Results enabled the reconstruction of a thicker film (> 0.5 mu m) as the layered structure, which consists of a gradient interlayer at the substrate, a relatively homogeneous layer as the bulk, and gradient overlayer at the film surface.