Authors Tiwari, A. ; Dorogin, L. ; Tahir, M. ; Stöckelhuber, K.W. ; Heinrich, G. ; Espallargas, N. ; Persson, B.N.J.
Title Rubber contact mechanics: adhesion, friction and leakage of seals
Date 28.12.2017
Number 54003
Abstract We study adhesion, friction and leak rate of seals for four different elastomers: Acrylonitrile Butadiene Rubber (NBR), Ethylene Propylene Diene (EPDM), Polyepichlorohydrin (GECO) and Polydimethylsiloxane (PDMS). Adhesion between smooth clean glass balls and all the elastomers are studied in both the dry state and in water. In water adhesion is observed for the NBR and PDMS elastomers, but not for the EPDM and GECO elastomers, which we attribute to the differences in surface energy and dewetting. Leakage of water is studied with rubber square-ring seals squeezed against sandblasted glass surfaces. Here we observe a strongly non-linear dependence of the leak rate on the water pressure ·P for the elastomers exhibiting adhesion in water, while the leak rate depends nearly linearly on ·P for the other elastomers. We attribute the non-linearity to some adhesion-related phenomena, such as dewetting or the (time-dependent) formation of gas bubbles, which blocks fluid flow channels. Finally rubber friction is studied at low sliding speeds using smooth glass and sandblasted glass as substrates, in both the dry state and in water. The measured friction coefficients are compared to theory, and the origin of the frictional shear stress acting in the area of real contact is discussed. The NBR rubber, which exhibits the strongest adhesion in both the dry state and in water, also show the highest friction in both the dry state and in water.
Publisher Soft Matter
Citation Soft Matter 13 (2017) 9103-9121
Tags hydrophobic surfaces rough surfaces temperature hysteresis

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