Glow discharges plasma formation

Monomers Not Polymerizable by Plasma Initiation. When styrene and a-methy1styrene were subjected to plasma treatment, the monomers became yellowish and only trace amounts of insoluble films were formed. The discoloration was intensified and extensive formation of dark films were observed if carbon tetrachloride was added as the solvent. No post-polymerization was detectable for these monomers. Generally styrene and a-methylstyrene readily undergo thermal polymerization. However, no thermal polymerization was possible for these monomers after having been subjected to plasma treatment for one minute or less. It has been demonstrated from the emission spectra of glow discharge plasma of benzene (6) and its derivatives (7 ) that most of the reaction intermediates are phenyl or benzyl radicals which subsequently form a variety of compounds such as acetylene, methylacetylene, allene, fulvene, biphenyl, poly(p-phenylenes) and so forth. It is possible that styrene and a-methylstyrene also behave similarly, so that species from the monomer plasma are poor initiators for polymerization. 

Pan, C., King, EL. (1993) Ion formation processes in the afterpeak time regime of pulsed glow discharge plasmas. J. Am. Soc. Mass. Spectrom., 4,727-732. 

Analysis of intrinsic InAs oxide formation in glow-discharge plasma... 

In the next section we describe the results of our study of chemical composition and formation kinetics of super-thin (5-10) nm intrinsic oxide films on the surface of InAs in oxygen plasma, in normal and glow discharge plasma, and the effects of cathode and anode sample polarization and influence of gas atmosphere, obtained in situ using the XPS method. 

Mass spectrometer studies of oxidant additions to fluoro- and chlorocarbon gases have demonstrated that the relative reactivity of atoms with unsaturate species in a glow discharge follows the sequence F -- O > Cl > Br (41), Of course, the most reactive species present will preferentially undergo saturation reactions that reduce polymer formation and that may increase halogen atom concentration. Ultimately, determination of the relative reactivity of the plasma species allows prediction of the primary atomic etchants in a plasma of specific composition. 

Plasma formation and the characteristics of glow discharge processes are subjects of extensive monographs [27,28],... 

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