Role of Preload in Adhesion of Rough Surfaces.

Adhesion between glass and bromobutyl and polydimethylsiloxane elastomers is investigated. We show that viscoelastic energy dissipation close to the opening (or closing) crack tip, and surface roughness, strongly affect the work of adhesion. We observe strong adhesion hysteresis and we show, in contrast to the Johnson-Kendall-Roberts theory prediction for elastic solids, that this results in a pull-off force, and effective work of adhesion to be dependent on the maximum loading force.