Bio-Inspired Interlocking Micro-Patterning for Tunable, Switchable and Selective Adhesion in Wet and Dusty Environments.

Achieving adhesion under unfavorable conditions, such as when van der Waals interaction is not available or in dust environments, is crucial in applications ranging from surgical sutures to wound-healing tapes, underwater adhesives, robotic grippers, and space grasping. Interestingly, plants, animals, and microorganisms living in such environmental conditions show surface morphological traits optimized to achieve mechanical interlocking. Thus, they achieve an effective work of adhesion thanks to the interplay of friction and interfacially-storable elastic energy, which otherwise typically suppress adhesion. In this work, the design and fabrication fundamentals for achieving tunable, switchable, and robust mechanical adhesion is provided 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 and validated experimentally. 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 the semiconductor industry.