Zhiang Zhang,Bing Han,Ruokun He,Shuaiqi Ren,Jiahao Fan,Wenzheng Han,Xumin Hou,Hesheng Wang,Zhuo-Chen Ma
Drawing inspiration from the doubly reentrant microstructures on springtail skins, surfaces exhibiting repellency to liquids with very low surface tension, are well developed. However, utilizing doubly reentrant microstructures for controllable wettability switching, especially for liquids with low surface tensions, still remains a challenge. Herein, a strategy is presented involving two-photon lithography-assisted molding to fabricate doubly reentrant soft microstructures (DRSMs) with real-time magnetic responsiveness. Owing to the high spatial resolution enabled by two-photon absorption and the dissolvable molding template, the 3D reentrant features are well preserved in the DRSMs based on the magnetic elastomer. Accordingly, the fabricated magnetic DRSMs exhibit switchable repellency for nearly all commonly used solvents within 1 s. Furthermore, the additional doubly reentrant micro-fence design surrounding the doubly reentrant micropillars allows the DRSMs to switch wettability even when fully immersed in liquids. These DRSMs demonstrate sufficient abilities for on-demand analyte enrichment and drug release. This work may not only serve as a design strategy to enhance the responsiveness of DRSMs but also significantly simplify the wetting switching system, which is highly attractive across various fields in biomedical and microelectronic applications.
Hydro- and oleophobic (namely, omniphobic) coatings or surfaces have many important applications, but tremendous challenges in fabrication aspects still remain. Herein, we report a bioinspired design and nanofabrication of three-dimensional (3D) tribrachia-post arrays with re-entrant geometry (3D TPARG) for superhydrophobic and oleophobic polymer films or surfaces. By simply controlling the temperatures and time to treat silica colloidal templates, we can readily fabricate 3D ordered polymer arrays of tribrachia-posts or hexagonal tribrachia-posts with re-entrant geometries that resemble the skin of a springtail insect after the template is removed. These polymer surfaces exhibit excellent and self-healing superhydrophobicity and oleophobicity even against temperature, acids, alkalis, and mechanical damage. Moreover, their liquid-infused nanostructured surfaces still display very good liquid-sliding ability for water and oils. Our 3D TPARG design strategy may help the development of omniphobic polymer coatings or surfaces for practical applications in self-cleaning surfaces, liquid transport, antifouling materials, and many other important fields.
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