Page 178 - Handbook of Surface Improvement and Modification

11.1 Methods and mechanisms of improvement of the coefficient of friction 173

Figure 11.10. EDS elemental mapping: the worn surface of the Epomet–PTFE-12.5 sliding for (a) 0 m, (b) 10 m
(c) 50 m, (d) 200 m, (e) 700 m, and (f) 1000 m against the steel ball, under 60 N normal load and 2 cm/s sliding
speed. The arrow indicates the relative sliding direction of the steel ball. [Adapted, by permission, from Shen, JT;
Top, M; Pei, YT; De Hosson, JTM, Wear, 322-323, 171-80, 2015.]
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ing velocity depended on molecular weight. The length of polymer chains noticeably
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influenced the tribological behavior of amorphous polystyrene. The molecular weight
increased with significant macromolecular mobility led to a greater density of chains in
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the contact with the atomic force microscopy tip (Figure 11.11). Higher chain density
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permits the van der Waals and acid-base interactions to take place. Thus, with higher