Bio-inspired micro-patterning for tunable, switchable and selective adhesion

Abstract of the related article: Achieving adhesion under unfavourable conditions, such as when van der Waals interaction is not available or in durst environments, is crucial in a number of applications, ranging from surgical sutures to wound-healing tapes, underwater adhesives, robotic grippers, and space grasping. Interestingly, plants, animals, and microorganisms such as mosquitoes, parasites, and plant diaspore, living in similar environmental conditions, show surface morphological traits optimised to achieve mechanical interlocking. Thus, they achieve an effective work of adhesion thanks to the interplay of friction and interfacially-storeable elastic energy, which otherwise typically suppress adhesion. In this work, we provide the design and fabrication fundamentals for achieving tailorable and robust mechanical adhesion, even switchable, effective under a general environmental condition, such as wet or dusty, bio-mimicking natural solutions. A theoretical framework for the design of mechanical adhesion, based on mean field continuum contact mechanics, is suggested, together with a facile micro-fabrication process. This study can pave the way for the development of new technologies, to be employed in situations where conventional adhesives may be ineffective, such as for surfaces exposed to water, solvent vapors, lubricants, high temperatures, dusty environments, high vacuum, or aerospace applications, or processes where switching and selective adhesion is needed such as grasping and sorting applications in semiconductor industry. The files are named after the numbering of the Figure in which they are used.