Bioinspired Photodetachable Dry Self-Cleaning Surface

Abstract

Geckos have adapted to the complicated natural environment with its excellent climbing ability. Current artificial gecko-inspired synthetic adhesives (GSAs) mimic gecko's attach-detach mechanism by creating anisotropic and hierarchical structures. Easy detachment and high self-cleaning capability are still the unsolved problems in GSAs. This study presents an unprecedented photodetachable mechanism of making bioinspired smart surfaces utilizing carbon dot (CD)-doped polydimethylsiloxane (PDMS) composites. Under ultraviolet (UV) irradiation, it could be triggered up to 80.46% reduction of adhesion force between PDMS-CDs bioinspired surfaces and contaminating particles. A load-drag-pull (i.e., LDP) test mimicking gecko's locomotion was adopted to test the dry self-cleaning capabilities of these bioinspired surfaces, where the falling rate of the model contaminates (PS micropellets; average size in diameter ∼8 μm) can reach up to 54.83% after seven repeated steps under UV irradiation. The significantly improved dry self-cleaning capability is attributed to the photothermal effect of CDs inside the PDMS matrix. The mechanism proposed in this work will find its applications in the realms of climbing robots, space adhesive devices, and self-cleaning, advanced gripping technologies for pick and place or assembly.