The influence of the substrate temperature on the growth mechanism of amine- and thiol-based plasma polymers: A comparative study

This work aims to provide new insights into the link between the growth mechanisms of functionalized plasma polymer films (PPFs) and the substrate temperature (TS). By means of AFM-based techniques, it has been demonstrated that the mechanical behavior of the coatings is dramatically affected by TS and the precursor employed (i.e., 1-propanethiol or 1-propylamine). While propylamine-based PPFs behave as hard elastic materials regardless of TS, propanethiol-based PPFs evolve from viscous liquids to elastic solids with increasing TS. This behavior can be understood considering the glass transition temperature of PPF. For both precursors, the latter is correlated to the cross-linking density controlled through the energy density brought by positive ions to the growing film. The growth mechanism of plasma polymer films prepared from two functionalized precursors is investigated as a function of the substrate temperature. A complete characterization of the physicochemical properties of the coatings is undertaken for each precursor (i.e., 1-propanethiol and 1-propylamine). Then, the obtained data are discussed to shed light on the influence of the precursor and of TS on the growth mechanism of the plasma polymers.image