Poly(methyl methacrylate) films deposited via non-equilibrium atmospheric pressure plasma polymerization using argon as working gas

A non-equilibrium atmospheric pressure plasma torch using argon (Ar) for sustaining plasma has been developed, and it was used to deposit plasma polymerized methyl methacrylate (PPMMA) films. The chemical structure and composition of the films obtained were examined by FT-IR and XPS analyses. It was found that, when raising the concentration of vaporized monomer to a certain level into the plasma, the plasma transitioned from a filamentary to a glow-like discharge, this resulting in a high retention of the monomer structure. Since the optical emission spectroscopy (OES) study of the plasma did not show any new excited species formed at higher concentrations of the monomer, it is clear that the fragmentation degree of the monomer in the plasma phase was quite low.