Authors: Robert M Bielecki Maura Crobu Nicholas D Spencer
Publish Date: 2012/11/04
Volume: 49, Issue: 1, Pages: 263-272
Abstract
We report a highly effective macroscopic nonaqueous lubrication strategy employing polymerbrushbased surface modification Polyalkyl methacrylates with hexyl dodecyl and octadecyl side chains have been prepared on both silicon and iron substrates by means of surfaceinitiated atomtransfer radical polymerisation Frictional properties of the three polymers have been evaluated in hexadecane ethanol and toluene For the case of the polydodecyl methacrylate the study additionally involved nine base lubricating fluids of different chemical natures with viscosities ranging from 4 to 2200 cSt at 20 °C By constructing a set of Stribeck curves at low values of speed × viscosity at constant load it was possible to identify an extended hydrodynamic lubrication regime and for P12MAbased coatings a lowfriction brushlubrication regime reinforced by timedependant effects which appeared to replace the mixed and boundary regimes observed for conventional lubricants Selfmated polydodecyl methacrylate brushes maintained low coefficientoffriction values eg 0012 in hexadecane over thousands of reciprocating cycles 100 m total distance under low speed × viscosity conditions 01 cm/s and 4 cSt
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