Gecko-inspired Carbon Nanotube-based Adhesives

Wall climbing lizards such as geckos have unique ability to attach to different surfaces without using viscoelastic glues. The micron-size hairs on the gecko feet make intimate contact and adhere to rough surfaces using van der Waals interactions. This carpet of hairs on the gecko feet also keeps the gecko feet clean and retains the adhesion in dusty environments. Synthetic gecko-inspired materials could form the basis of a new class of adhesives that would include two contradictory properties of self-cleaning and high adhesion. These adhesives will be useful for applications in the areas of wall-climbing robots, reversible adhesives, and adhesives suitable for use in space and electronic applications. In my presentation, I will discuss our strategy of using micro-patterned vertically aligned carbon nanotubes (CNT) to mimic the micron-size hairs found on the gecko feet. These CNT structures can be transferred to flexible plastic films to create flexible adhesive tapes. The hierarchical patterns of individual carbon nanotubes (8-10 nm in diameter) arranged in micron-size patches (50-500 mms) are important in mimicking the adhesion and self-cleaning properties observed by geckos.