Contact Adhesion of Thin Gold Films on Elastomeric Supports: Cold Welding Under Ambient Conditions

Thin gold films placed in contact on compliant elastomeric poly(dimethylsiloxane) supports weld together. This ``cold welding'' is remarkable both for the low loads required and for the fact that it occurs under ambient laboratory conditions, conditions in which the gold surfaces are covered with films of weakly adsorbed organic impurities. These impurities are probably displaced laterally during the welding. Welding can be prevented by the presence of a self-assembled gold(I) alkylthiolate monolayer on the gold surfaces. The welded contacts have low electrical resistivity and can be made thin enough to transmit light. This system is a promising one with which to study interaction between interfaces.