Surface Textures on Nonplanar Surfaces Fabricated via Modified Soft Lithography and Electrochemical Etching

Three-dimensional surface textures on non-planar surfaces are increasingly important for optical, electronic, biomedical, and mechanical applications. Traditional micro-fabrication methods, based on photolithography and dry/wet etching processes, were originally developed for planar surfaces. This paper introduces a novel photolithographic technique that employs a large-size soft mask to fabricate surface textures onto curved metal surfaces. A soft lithography mask was successfully developed by transferring master patterns onto an elastomeric polymer film, (which serves as the soft mask. The soft mask was then directly applied to a curved (r other complex-shaped surface for the photolithography process, followed by electrochemical etching. It has been confirmed that the fabricated soft mask can reproduce the master pattern on a curved surface with controlled texture feature shapes and dimensions. As an illustration of potential applications, the tribological behavior of the textured sample was investigated using reciprocating friction testing. Compared to untextured samples, testing results demonstrated friction reduction and potential energy savings with samples textured using the soft mask technique. The research not only holds significant value for enhancing material corrosion protection technology—such as improving surface performance, precise texture control, and expanding the scope of material applications—but also has potential implications for the surface texturing of curved components in aircraft to improve aerodynamics, and in the field of flexible electronics to integrate more functional components.