Conformably Skin-Adherent Piezoelectric Patch with Bioinspired Hierarchically Arrayed Microsuckers Enables Physical Energy Amplification

An intimate contact interface between wearable energy harvesting devices and nonflat human surfaces is critical for harvestingenergy from the body's movements. The device can only absorb thedeformation strain under stable interfacial adhesion to biologicalsurfaces. Past developments have mainly examined the active layer ofsuch devices, but the device/body adhesive interface effects are rarelyconsidered. Here, we introduce a hierarchically arrayed octopus-inspiredpattern (h-OP) formed on piezoelectric composite patch devices. The h-OP enables robust wet adhesion to skin because its dome-likearchitecture achieves interfacial adhesion by generating cohesive forcesamong liquid molecules. We usedfinite element method simulation toinvestigate decohesion behaviors with bending-induced stress distribu-tion. The enhanced adhesion provided efficient energy generation understrain according to body movements. With 90 degrees wrist bending, the h-OP devices demonstrated approximately triple the energygeneration of implementations with no pattern, exhibiting stable adhesion and high energy generation efficiency, even on the wet skin