Nucleation, first growth stages and structure of nano-sized polymer coatings deposited from active gas phase

Abstract

This paper presents an analysis of the structural-morphological, kinetic patterns of the initial growth stages of single-component and composite (polymer-polymer and metal-polymer) nanoscale coatings based on the products of electron-beam dispersion of polymers. The main features of the deposition processes from the active gas phase occurring on the substrate surface and the established size dependences of the structure and molecular composition are explained on the basis of the adsorption-polymerization mechanism for the formation of coatings. It was established that among the most important features of the deposition process from the active gas phase is the simultaneous flow of polymerization and structure formation of adsorbed molecular fragments of the polymer under the conditions of exposure of the active components of the plasma, dispersive filler, and the substrate surface. This feature has a decisive influence on the nucleation of polymer particles, the molecular structure and morphology of nanoscale layers, as well as the dependence of their properties on thickness. Using the PTFE and PE coatings, it was shown that the orientation and ordering of the formed layers changes during the coating growth: at the initial stages of deposition in the layer up to 150 nm, the molecules are oriented predominantly parallel, and in thicker layers due to the bulk structure formation perpendicularly substrate surface. When deposited on the surface subjected to plasma treatment, the growth rate of the formed coating at the initial stages of growth increases by more than 5 times. At the same time, such layers contain predominantly linear molecules with a relatively lower molecular weight. The introduction of micro-and nanoscale polymer coatings in the process of their growth of the formed silver or copper nanoclusters leads to the formation of highly oriented, continuous, highly dispersed layers already at the initial stages of growth. The orientation of the macromolecules of the matrix with the maintenance of Ag or Cu nanoclusters in it has parameters characteristic of single-component coatings. In PTFE+Mo coatings, a linear dependence of molecular orientation on the layer thickness appears. In composite coatings containing silver nanoclusters, the effect of selective plasmon absorption was established.