Adhesion Reduction at Solid/Liquid Interfaces Based on Topologically Optimized Microtextures

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