(5dk) Surface Interactions in Polymer and Biological Systems at the Micro and Nano Scales

Characterization of the adhesion, tribological properties and dynamics of polymer and biological surfaces has been of great interest both experimentally and theoretically for many years. Improving our fundamental understanding of the interactions of polymer surfaces and biological systems at the micro and nano scales is needed to develop further techniques in chemical engineering and materials science. This poster will show our recent progress in:

(1) Adhesion and detachment mechanisms of polymer thin films, especially the transient surface deformations, flows and dynamics during both detachment and attachment (coalescence or spreading) of two polymer films. We find that there is a continuous transition between the failure modes of viscous liquids and glassy solids. A new type of self-organized periodic transient surface fingering pattern and instability was also found to generally exist during the adhesive contact and coalescence of two polymer films.

(2) Understanding the gecko adhesive and related biomimetic Systems. We present a recent theoretical analysis that models the quick attachment and detachment of gecko feet based on a tape mode, and demonstrate the role of the geometry in the enhancement of the adhesion and coupled friction; we also show an analysis of the adhesion and coupled friction of bio-inspired patterned surfaces. Our results, when considered with recent experiments, suggest criteria for simultaneously optimizing the adhesion and friction of patterned surfaces.