A model acrylic copolymer system was used to study the processes involved in the transfer of a thin viscoelastic film from a weakly adhesive elastomeric substrate to a more strongly adhesive surface. The film consisted of a layer of acrylic diblock copolymer micelles that was spun cast onto a silicone elastomer from a suspension in butanol. A circular portion of the layer was transferred to a hemispherical glass indenter with which it was brought into contact. The transfer of the film during tensile loading of the indenter began with nucleation of a cavity at the film/elastomer interface and was followed by delamination of the film at this interface. Statistical variations in cavity nucleation for identical loading conditions were quantified by defining a Weibull modulus similar to that used to describe the failure of brittle materials. The average energy release rate required for cavity nucleation at a fixed induction time increased with film thickness in a way that is consistent with the existence of a critical value of the hydrostatic tension at the film/substrate interface. This critical hydrostatic tension was comparable in magnitude to the elastic modulus of the substrate and was about ten times the elastic modulus of the thin film.
ASJC Scopus subject areas
- Physics and Astronomy(all)