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Omniphobic surfaces, capable of repelling all types of liquids, are fundamentally reliant on the micro/nano doubly re-entrant structures, these overhanging structures, however, are prone to break under mechanical loading. Here, we report a robust technique to faithfully transfer an array of soft doubly re-entrant microstructures onto a target substrate, circumventing the limitation of demolding soft overhang structures, to realize a resilient omniphobic surface for the first time. The resulting surface not only exhibits omniphobic property, but also robust durability after substantial normal and shear mechanical stresses. The side view of the deformation and recovery of the structures against mechanical loads was captured under a microscope to help reveal the underlying mechanism. The innovative method presented in this study is scalable for the production of mechanically robust, omniphobic surfaces on a large scale. Such advancement facilitates the large-scale manufacturing of durable micro- and nanoscale surface textures, making them viable for practical applications. 

We present a versatile method to create 3-D surfaces with complex hierarchical microstructures that mimic the patterns found on springtail skin. Our method innovatively merges two fixed-spacing patterns at different scales to create patterns with varying spacing but does not require precise alignment. The key is to utilize localized stretching strain when gradually laminating a thin microstructured elastomer layer onto a wavy substrate. To demonstrate this new fabrication process, we laminated a micro-pillar thin polydimethylsiloxane (PDMS) film on a wavy PDMS substrate with millimeter-scale inverted pyramidal holes. This resulted in hierarchical surface micropillars that display varying spacings along the peaks and the valleys of the wavy substrate. To our best knowledge, this is the first report to generate controllable micro-patterns with a gradient spacing from fixed-spacing patterns. Our new process overcomes one of the major challenges in producing bio-inspired patterns with diverse variations for studies of biomimicry and biomutualism.