ABSTRACT
Observations made with a scanning electron microscope provided direct evidence for a soft polyester-polydimethyl-siloxane block copolymer substrate undergoing extensive surface force induced plastic deformation upon contact with micrometer or submicrometer size spherical particles. To investigate surface force deformations of materials and, in particular, the effect of tensile forces on substrate deformations, it is desirable to examine the contact of particles on a substrate having a Young’s modulus between that of typical elastomers and that of a typical thermoplastic. Anomalously large menisci, interparticle bridging and particle encapsulation phenomena were observed between rigid micrometer size spherical particles and a polyester-polydimethylsiloxane alternating block copolymer substrate. The observed menisci, which arise from surface force induced tensile interactions, are approximately an order of magnitude larger than expected from the analysis of adhesion induced deformations based on the Johnson-Kendall-Roberts theory.
