Manufacturing of\nBionic Adhesion Microstructure with\nExpanded Ends Based on Electroplating in the Restricted Area

The organisms of animals with full spatial motion ability\npresent\nfine and complex 3D structures, showing reliable adhesion ability\nto the substrate. As core issues, the design and manufacture of complex\nmorphology are essential in bionic adhesion technology. Specifically,\nthe end-expanded microstructure array of high adhesion under low preload\nhas widespread potential in the nondestructive fixation and handling\nof fragile objects. In the fabrication of end-expanded microstructures,\nthe design and manufacture of metal molds with good mechanical strength\nare the key. In this paper, a microfabrication technology for manufacturing\nnickel molds based on three-dimensional printing and electroplating\nwas proposed. The effect of the electric field inhomogeneity on the\nelectrodeposition morphology was systematically studied. Typical bionic\nadhesives with expanded ends were obtained by a roll-to-roll hot embossing\n(R2R-HE) process. The normal adhesion force of the bionic adhesives\nis 9.5 N/cm<sup>2</sup>, which is comparable to that of the gecko.\nThe electroplating process assisted by 3D printing provides a new\napproach for the fabrication of complex bionic morphologies and large-area\nbionic adhesion structures.