Plasma polymerization of some organic compounds and properties of the polymers

Abstract

Plasma polymerizations (under 13.5‐MHz radiofrequency inductively coupled glow discharge) of some organic compounds are investigated by their properties (elemental analysis, surface energy, and infrared spectra) and their relations to the concentrations of free radicals in the polymers as detected by electron spin resonance (ESR) spectroscopy. Monomers that have been investigated are hexamethyldisiloxane, tetrafluoroethylene, acetylene, acetylene/N2, acetylene/H2O, acetylene/N2/H2O, allene, allene/N2, allene/H2O, allene/N2/H2O, ethylene, ethylene/N2, ethylene oxide, propylamine, allylamine, propionitrile, and acrylonitrile. Plasma‐polymerized polymers generally contain oxygen, even if the starting monomers do not contain oxygen. This oxygen incorporation is related to the free‐radical concentration in the polymer. Molecular nitrogen copolymerizes with other organic monomers such as acetylene, allene, and ethylene, and their properties are very similar to those of plasma‐polymerized polymers from nitrogen‐containing compounds such as amines and nitriles. The addition of water to the monomer mixture reduces in a dramatic manner the concentration of free radicals in the polymer and consequently the oxygen‐incorporation after the polymer is exposed to air. The concentrations of free radicals (by ESR) are directly correlated to the change of the properties of plasma‐polymerized polymers with time of exposure to the atmosphere. These changes are primarily the introduction of carbonyl (and possibly hydroxyl) groups. The addition of water to the plasma introduces these groups during the polymerization.

Enhancement of polymer hydrophobicity by SF6 plasma treatment and argon plasma immersion ion implantation

“…Yasuda et al, 13 for instance, have shown by using infrared absorption spectroscopy that the hydroxylation of plasma-deposited acetylene films increased continuously for >15 months after deposition. Assuming that such remnant radicals are present also in plasma-treated polymers, exposure of the treated PTFE to air can lead to the incorporation of oxygen, as observed by XPS, via post-plasma reactions.…”

“…It is worthwhile to comment that free radicals (or dangling bonds) have been observed 10,13 to stay active in plasmadeposited polymeric films for long periods of time. Yasuda et al, 13 for instance, have shown by using infrared absorption spectroscopy that the hydroxylation of plasma-deposited acetylene films increased continuously for >15 months after deposition.…”

Characterization of Plasma Polymerized Hydrocarbons Using CP-MAS Carbon- 13 NMR

“…The most widely used spectroscopic tools for analyzing these materials is Fourier transform infrared spectroscopy (FTIR) [1][2][3][4] and electron spectroscopy for chemical analysis (ESCA). 1 -3, 5 Although both techniques are of utility, they have significant limitations.…”

Primary Amine Implantation Onto Polypropylene Surfaces from Melamine and Urea RF Plasmas.

“…It has also been found that ammonia plasmas does not produce primary amine implantation efficiently [26] and accordingly saturated and unsaturated amine-plasmas were suggested to be employed as an alternative [27][28][29][30][31][32][33][34][35]. Successful surface amination of various polymeric substrates were reported, however due to the diversity of plasma reactors, nature of plasma gases and experimental conditions direct comparison of results from these experiments is difficult.…”