Bioinspired Design of Three-Dimensional Ordered Tribrachia-Post Arrays with Re-entrant Geometry for Omniphobic and Slippery Surfaces

Abstract

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.

Bioinspired Superwettability Micro/Nanoarchitectures: Fabrications and Applications

“…Intriguingly, such reentrant structures are also observed on the surface of protein‐based nanoparticles, which provides protection against contamination . As such, reentrant design is essential for designing surfaces with antioil, anti‐biofouling, and anticorrosion functions …”

Fabrication of a flexible transparent superomniphobic polydimethylsiloxane surface with a micropillar array

“…Superomniphobic surfaces that can repel a wide range of liquids with high contact angle and low sliding angle have received increasing attention as they have versatile applications, including antibiofouling, 1,2 liquid transportation, 3,4 drag resistance reduction 5,6 and self-cleaning surfaces, [7][8][9][10] etc. Building such surfaces usually requires the combination of micronanostructured hierarchical surfaces and the subsequent treatment of low surface energy chemicals 11 The chemical treatment can be implemented by peruorocarbon materials onto structured surfaces, including vapor deposition [12][13][14][15] and dip-coating.…”

“…Building such surfaces usually requires the combination of micronanostructured hierarchical surfaces and the subsequent treatment of low surface energy chemicals 11 The chemical treatment can be implemented by peruorocarbon materials onto structured surfaces, including vapor deposition [12][13][14][15] and dip-coating. 7,8,[16][17][18] To make hierarchical micro/nano structures, methods such as stacking micro and nanospheres, 9,16 texturing bers, 17 and spray coating, 7,12,18,19 have been commonly used while fabrication of such surfaces with special surface topography such as nanopatterned micropillars, usually involves photolithography or reactive ion-etching using sophisticated tools with complex preparation process. [13][14][15][19][20][21][22][23][24] Recently, the unique structure observed on the skin of springtails has been reported to have extraordinary liquidrepellent characteristics.…”

“…25 It is believed that the so-called doubly-re-entrant structures attribute to the super-repellency. Inspired by the surface structure of springtail skin, we have successfully fabricated bio-inspired superomniphobic surface mimicking this doubly-re-entrant structure, 9,10 through simply heat-treating silica colloidal templates combined with the fabrication of polymer inverse opals. In addition, several works on transparent and exible PDMS-based superomniphobic surfaces have been reported.…”

Selective Liquid Sliding Surfaces with Springtail‐Inspired Concave Mushroom‐Like Micropillar Arrays

“…Consequently, it is now well understood that negative slope shapes such as the re‐entrant profile of microstructures are critical factors in achieving robust and energetically favorable superomniphobic surfaces . More recently, several research groups effectively demonstrated omniphobic, liquid sliding and slippery surfaces by drawing inspiration from nature such as springtail, rice leaf, and pitcher plant . These liquid repellent surfaces have many practical applications, ranging from academia to precision industries such as microfluidics, electronic devices, oil–water separation system, and oil collecting or transportation area …”