Adhesion Reduction\nat Solid/Liquid Interfaces Based\non Topologically Optimized Microtextures

Artificial microtextures adopted to achieve adhesion\nreduction\nhelp avoid the vulnerability associated with chemical coatings. Most\ncurrent microtextures strongly rely on biological inspiration or designers’\nphysical intuition. There are also manufacturing challenges due to\nthe complex geometrical configurations. Topology optimization can\ndetermine the structural configurations encompassing geometric information\non topology, shape, and size and ensure the manufacturability of the\noptimized microtextures by controlling the feature size corresponding\nto a specified fabrication process. Herein, we present an approach\nto reduce the liquid adhesion on solid surfaces by employing artificial\nmicrotextures with hexagonal periodicity, where the microtextures\nare inversely designed through topology optimization. The microtextures\nare fabricated of polydimethylsiloxane by using a soft lithography\nprocess. The liquid adhesion on the microtextures is measured via\nthe tilting plate method. Experimental results demonstrate that the\ntopologically optimized microtextures can significantly reduce the\nliquid adhesion by 45.0%, which is achieved by the robust Cassie–Baxter\nstate of the wetting behavior. The topologically optimized microtextures\ncan also support the robust Cassie–Baxter state underwater\nand accelerate the speed when the droplets slide off the surface with\nthem. The findings can be utilized in the context of the reduction\nof underwater drag and bioadhesion.