Reversible Solid Adhesion for Defense Applications; Rept. for 15 Jan-31 Dec 2007

摘要

In this six month project, we have investigated the adhesion behavior between two solid contacting surfaces with the aim of producing both large bond strength, and under conditions of tangential motion weal bond strength, thus achieving reversible adhesion. For this purpose we have used a newly developed dynamic adhesion tester, nominally flat and spherical surfaces ranging in size from micron to millimeter. Based on the experiments, it was found that the faster the velocity in the horizontal (friction) direction, the lower the bond strength, which could be used for debonding. To achieve a strong bond, larger surface areas with a softer material (e.g., gold coating or polymer-based material) should be used. The bond strength also depends on the surface roughness, applied contact force and the presence of humidity. For example, a polymer-based coated sample gave a 167 X reduction in the bond strength under small tangential motions. These results clearly indicate that the bond strength between solid surfaces can be reversed in a controlled manner. This concept can be further advanced for specific military applications and environments and it has the potential to succeed as solid surfaces are very controllable and can be engineered for many different hostile environments.