Modeling the chemistry of plasma polymerization using mass spectrometry

摘要

The goal of the project is a solvent free painting shop. The environmental technologies laboratory is developing processes of plasma etcing and polymerization. Polymerized thin films are first-order corrosion protection and primer for painting. Using pure acetylene we get very nice thin fims which were not bonded very well. By using air as bulk gas it is possible to polymerize, in an acetylene plasma, well bonded thin films which are stable first-order corrosion protections and good primers. UV/Vis spectroscopy shows nitrogen oxide radicals in the emission spectra of pure nitrogen and air. But nitrogen oxide is fully suppressed in the presence of acetylene. IR spectroscopy shows only C=O, CH_2 and CH_3 groups but no nitrogen species. With the aid of UV/Vis spectra and the chemistry of ozone formation it is possible to define reactive traps and steps, molecule depletion and proceses of proton scavenging and proton loss. Using a numerical model it is possible to evaluate these processes and to calculate theoretical mass spectra. Adjustment of theoretical mass spectra to real measurements leads to specific channels of polymerization which are driven by radicls especially the acetyl radical. The estimated theoretical mss spectra show the specific channels of these chemical processes. It is possible to quantify these channels. This quantification represents the mass flow through this chemical system. With respect to these chemical processes it is possible to have an idea of pollutant production processes.