Effects of Gamma Irradiation on Adhesion of Polymer Microstructure-Based Dry Adhesives

Irradiation of polymer-based directional dry adhesives with gamma photons has been performed. This irradiation is commensurate with the radiation that an adhesive sample would be exposed to if deployed in a nuclear glove box or other high-radiation environment. Before and after irradiation, samples were tested using a three-axis adhesive testing stage and were analyzed via a scanning electron microscope and a water droplet contact angle analyzer. At doses in excess of 270 kGy, the adhesive performance began to deteriorate, continuing to an overall performance reduction of 55% at a dose of [approximately]500 kGy. Significant changes in the surface energy of the bulk polymer are also indicated by changes in water droplet contact angles, contributing to the adhesion performance loss. Such analyses allow for quantitative statements to be made about the expected performance of these adhesives when deployed in high-radiation environments.