Structural interpretation of plasma-polymerized propargyl alcohol

Vapor of propargyl alcohol under reduced pressure was glow-discharged for plasma polymerization by which hydrophilic polymer film could be deposited onto a solid substrate. The hydrophilic property was more enhanced with use of the same monomer containing water. An interpretation of chemical structures of the polymer molecules was therefore attempted to discover the reason of the hydrophilic property. The polymer materials were subjected to IR spectroscopy, ¹³C-NMR and ¹H-NMR spectroscopies, elemental analysis, number average molecular weight determination, mass spectrometry, and other wet chemical analysis for . The IR spectra of the polymers showed the presence of OH, C?O, and C?C groups with a disappearance of C?C group of the monomer. It was also found that the molecular formula of a solvent extract of the polymer derived from the plain monomer was C₂₆H₃₆O₉ ≒ 490, involving four hydroxyl, one carbonyl, and two to three olefinic unsaturation groups within a unit molecule. On the other hand, the polymer from 60% water-containing monomer showed its molecular formula as C₄₄H₆₆O₁₈ ≒ 890, containing seven to eight hydroxyl, two carbonyl, and one to two olefinic unsaturation groups. This information was used to establish the symbolic chemical structures of the polymer molecules. It has been found that both polymers were not as much crosslinked as other plasma polymers because of having side chains with fewer branching. The oxygen atoms were retained in the polymer not only as the forms of OH and C?O but also as a member of the principal frame of the polymers.