Abstract
Chemical structures of solid films produced by plasma polymerization of pyridine and aniline, the representative examples of nitrogen-containing aromatic monomers, were elucidated. The work was aimed to reveal the nitrogen-containing polar groups retained in the polymer matrices by which hydrophilic nature of the plasma polymers was introduced. IR and NMR spectroscopies with the aid of some chemical modifications of the polar groups showed the presence of amines, nitrile, imines (including hetero-cyclic ring), and amides. While these groups were commonly observed in either polymer, relative abundances of the groups were different. Additional informations from elemental analysis, molecular weight determination, and high-resolution mass spectrometry suggested different modes of net work between the structures of the two polymers; more rigid and cage-like configuration was considered for the pyridine polymer in contrast to the aniline polymer, the latter of which involved some flexible free-rotation sites of the alkyl chain. The chemical structures of the two polymers were finally proposed. It was also found that some nitrogen atoms were eliminated during the polymerization process, while some oxygen atoms were introduced within the polymers possibly because of air oxydation underwent after the polymers exposed to atmosphere.
