Product and Plasma Characterizations

The highly cross-linked nature of plasma-polymerized films dictates that in vestigations of structure, composition, and reactivity must be carried out via probes of the solid state. Thus, to date, the most meaningful studies of PP have come from i.r., XPS, electron microscopy, e.s.r. and surface free energy studies. It is not unreasonable to apply surface-sensitive techniques such as XPS to these systems since in most cases the surface is characteristic of the bulk. - Investigations of the gas plasma itself may be carried out by means of electric probes (to determine plasma potentials and electron temperatures), mass spectrometry, and spectroscopic studies. Many of these methods have been applied to plasma-polymerized systems during 1979/80 as summarized below. 

Several authors have examined the nature and behaviour of free radicals trapped in polymer films as a result of plasma polymerization. Some noted the reaction of the radicals with Oj when exposed to air but not with N. The behaviour of radicals upon heating plasma-polymerized films was also studied.  

The number of workers characterizing the gas plasma itself either by electrical probes or by sampling would seem to be increasing. The 

Several studies have presented the results of plasma polymer characterization by various techniques 3 - s - 52 such as i.r., wettability, and adhesion characteristics. The wettability properties of plasma-polymerized styrene films were dependent upon the degree of incorporation of N into the film. Severe polymerization conditions (high power, low pressure) resulted in a reduction in aromaticity of PP films. The electrical properties of certain plasma polymers were reported. Experiments to optimize coating parameters for the continuous coating of a moving substrate have been carried out. The reactivity of plasma polymers 

Yamaguchi, S. Nakamura, and A. Sav/a, Purazumo Jugo, Tokubetsu Toroukai, 1979, 252. 

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Since this is the first review of PP to appear in this series it is appropriate to begin with a brief description of the technique and the characteristic features of its products. The remainder of the review is divided into four sections kinetic and mechanistic studies of plasma polymerization, product and plasma characterization, applications of plasma polymerization to achieve technological goals (including patents), and finally plasma-induced polymerization of liquid monomers. 

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