Bioinspired Underwater Adhesion to Rough Substrates by Cavity Collapse of Cupped Microstructures

Underwater or wet adhesion is highly desirable for numerous applications but counteracted by the liquids in contact which weaken intermolecular attraction. The problem exacerbated conjunction with surface roughness when partially remain grooves dimples of substrate. In present study, a cupped microstructure cavity inspired suction organs aquatic animals proposed. microstructures (cup radius 100 µm) are made from polyurethane using two-photon lithography followed replica molding. Adhesion to rough substrates emulated experimentally micropatterned model substrate varying channel widths. Pull-off stresses found be about 200 kPa, i.e., twice atmospheric pressure. Evaluation force–displacement curves together situ observations reveal mechanism, involves adaptation and an elastic force induced collapse that holds sealed during retraction. This new microarchitecture may pave way next generation applicable real, surfaces under conditions.