Scaling Analysis of the Morphology of Nanostructured Poly(p-xylylene) Films Synthesized by Vapor Deposition Polymerization

The surface morphology of poly(p-xylylene) thin films prepared by the vapor deposition polymerization technique in the range of polymerization temperatures from -23 degrees C to + 35 degrees C was studied by atomic force microscopy. Silicon (100) single crystal wafers and freshly cleaved mica were used as substrates. To analyze the roughness of polymer films, we studied the height-height correlations for pairs of points on the surface as a function of the distance between them using the scaling approximation. An increase in the substrate temperature results in a decrease in the roughness exponent at temperatures higher than the poly(p-xylylene) glass transition temperature, leading to an increase in the surface irregularity. At polymerization temperatures of + 20 degrees C to + 35 degrees C and a low rate of polymer film growth on Si substrate of similar to 0.5-1 nm/min, the roughness exponent alpha = 0.73 +/- 0.02 can be interpreted as a result of bulk diffusion of the monomer. The effect of the nature of the substrate, growth rate of the polymer film, and temperature of the substrate on scaling coefficients of the synthesized films was discovered. An increase in the growth rate of the polymer film results in an increased roughness exponent.