Peeling rate coefficients

The rate coefficients for chemical stopping decreased with time for both substrates in a pattern similar to that for peeling. Thus, as the accessible reducing endgroups occupied progressively more ordered regions of the structures, their reactivity toward chemical stopping also decreased. 

ND = Rate coefficients not determined due to simultaneous complete peeling or dissolution... 

To evaluate the wear resistance of the PMMA brush, a continuous friction test for 600 s was performed by sliding a stainless steel ball on substrates covered with 20 nm of thick polymer brush or cast film under a load of 0.49 N at a sliding rate of 90 mm/min (fig. 5.12). In the early stage of the friction test, the friction coefficient of the brush surface increased to 0.5 from 0.25, but there was no further increase during continuous friction, as shown in fig. 5.12a. On the other hand, the friction coefficient of the cast film continuously inaeased with friction cycles (fig. 5.12b), and the surface polymer gradually peeled away to form debris ( wear elements ), some of which was adsorbed on the surface of the probe ( transfer particles ) or left in the wear track, interfering with the smooth sliding of the probe. Finally, the PMMA layer in the wear track had completely peeled off. 

For any values of P and D there will be an angle, 6r, at the debond point as shown in Fig. 10. For an applied force P only a fraction, i.e. (1 — fx)P, is applied at the peeling front since friction arises in the roller, where fx is the coefficient of friction. The energy release rate, G, for this roller-assisted peel test is given by ... 

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