Meeting Abstract
The strong, yet reversible adhesive performance of geckos has been admired for many years. However, despite significant interest, there is still uncertainty about the governing adhesive mechanisms. For example, adhesive performance in variable temperature and humidity challenges two leading adhesion hypotheses: capillary adhesion and gecko setal softening. Both hypotheses consider variable relative humidity, but neither fully explain the interactive effects of temperature and humidity. Interestingly, gecko-inspired synthetic adhesives (GSAs) have shown similar adhesive performance in the same variable temperature and humidity environments. These GSAs represent a more controllable system that can be leveraged to test both hypotheses independently. Therefore, we conducted a comparative study between live geckos and GSAs in variable temperature and humidity to investigate the roles capillary adhesion and material softening have on gecko adhesion. In our gecko experiments, we identified an optimal range of environmental conditions for gecko adhesion. However, our GSA data remained relatively static across the same environmental conditions. This disparity in adhesive performances points towards both capillary adhesion and material softening playing significant roles in gecko adhesion, and only capillary adhesion affecting GSA adhesive performance. These results will help drive predictions into how geckos utilize various habitats, aid in the fabrication of new GSAs for robotics, biomedical, and commercial applications, and highlight an opportunity to use the gecko adhesive system as a model to explore an understudied area of basic surface science: temperature and humidity effects on micro and nanoscale systems.
