Stress internal curling force

Figure 11.2 Curling force o d, the product of the internal stress and thickness d of the plasma-deposited layer, versus d the three curves correspond to layers obtained by plasma polymerization of the following monomers O, pyridine A, acrylonitrile , thiophene , tetramethyldisiloxane.

First, internal stress is plotted against arbitrarily selected single parameters just as the data in glow discharge polymers were presented. All films prepared by LPCAT showed the same kind of curling force, from which internal stress can be calculated. Figure 11.6 shows the influence of LPCAT operation parameters on... 

With a cross linked structure, it is often characteristic of plasma polymers, that internal stress builds up as the film thickness increases. The internal stress can in fact be measured from the curling force produced when plasma polymer films of known thickness are deposited on a substrate (e.g. LIffE) for which the bulk modulus is known. Typical data are shown in Figure 13. 

Figure 13. Curling force as a measure of internal stress as function of thickness for plasma polymers prepared from fluorobenzenes.

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