Fabrication of Stretchable Superamphiphobic Surfaces with Deformation‐Induced Rearrangeable Structures

Abstract

we now profit from an improved understanding of the mechanisms of a superamphiphobic surface, a less complex method of preparation and a high mechanical stability of the surface are still two of the main challenges that have hindered its widespread adoption. [7] Recently, superliquid-repellent surfaces with deformation-resistant performance are becoming increasingly significant in various situations such as flexible electronics, [8] artificial skin, [9] textile dressings, [10] and liquid manipulation. [11] Currently existing superamphiphobic surfaces appear to lose their superliquid-repellency to nonpolar liquids under small deformation, in particular when being stretched. [12] The breakup of the surface structures during stretching usually cause the lowsurface-tension liquids on the surface transiting from the Cassie state to the Wenzel state (fully wetted) easily. Pan et al. reported an excellent textile which repels the wetting of liquid nitrogen with surface tension of 8.8 mN m −1 , yet it loses the superoleophobicity when being stretched to 20%. [12a] Even till now, there is no effective way proposed to solve this problem that the loss of superamphiphobicity due to stretching.In this work, we fabricated a stretchable surface whose superamphiphobicity is maintained during stretching via construction of spontaneously rearrangeable microstructures, and which is fabricated by spray-coating silicone nanofilament (NF) on a pre-stretched elastic substrate. A single NF usually has a diameter of the order of 10 nm and can form on the overhanging structures due to its round, spaghetti-like shape. [6c] After spray-coating process, the NFs together with their assembly lead to a re-entrant geometry from tens of nanometer to hundreds of micrometers providing the underlying structure for a superamphiphobic surface. Releasing the tension of the substrate after fabrication leads to relatively compacted structures. During the surface stretching process, we observed the rearrangement of these structures in situ. The rearrangement of the structures includes the breakup of the largest NF clusters and the movement of the structures with respect to each other due to surface stretching. Through monitoring the size and density of the structure, the reason why the surface remains its superamphiphobicity in a high strain was understood. This surface was further utilized to fabricate a programmable liquid manipulation system to achieve drop coalescences and synthesis of asymmetric hydrogels.Stretchable superamphiphobic surfaces with a high deformation resistance are in demand to achieve liquid-repellent performance in flexible electronics, artificial skin, and textile dressings. However, it is challenging to make mechanically robust superamphiphobic coatings, which maintain their superliquid repellency in a highly stretched state. Here, a stretchable superamphiphobic surface is reported, on which the microstructures can rearrange during stretching to maintain a stable superamphiphobicity even under a high tensile strain. The sur...

A Skin‐Inspired Design Integrating Mechano–Chemical–Thermal Robustness into Superhydrophobic Coatings

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and thermal properties of engineered surfaces to impart multifunctions in complex operating environments including varying temperature and humidity is critical. Of special interest is natural superhydrophobic surfaces found on the skins of many living organisms, [2][3][4][5][6] and bioinspired artificial coatings widely adopted in energy-related processes such as self-cleaning, [7][8][9] thermal management, [10][11][12] energy harvesting, [13][14][15] droplet manipulation, [16,17] antifogging, [18,19] anti-biofouling, [20] and anti-icing. [21][22][23] In spite of extensive progress, practical implementations of superhydrophobic coatings with preferred functionalities and durability for energy saving dictate a wide-spectrum robustness including mechanochemical strength, high adhesion with substrates, and flame resistance, a challenge remaining unsolved to date.However, it appears difficult to mutually achieve all these features in one design.

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Advances in the Fabrication and Characterization of Superhydrophobic Surfaces Inspired by the Lotus Leaf

“…It was shown that by increasing the silane loading, although the transparency of the surface decreased, the WCA increased. In another study, Zhou et al [ 48 ] first spray-coated PDMS (as the binding layer) and then a solution of silicone nanofilaments (NF) in toluene on a pre-stretched substrate (a commercial cis-1,4-polyisoprene tape), followed by curing the surface at 80 °C for 2 h, and fluorination by chemical vapor deposition ( Figure 10 ). The NFs formed dense re-entrant nano- and micro-scale structures that showed repellency against water and oil (n-hexadecane) for at least one thousand stretch-release cycles, resulting in a durable stretchable superamphiphobic surface.…”

“…Scale bar = 200 μm; ( c ) SEM images of the NFSS surface at various magnifications. Scale bar = 50 μm ( top ), 2 μm ( bottom ), and 500 nm (inset); and ( d ) schematic illustration of microstructures on the NFSS after releasing the surface from the stretched state (Reproduced from [ 48 ] with permission from John Wiley and Sons).…”

A versatile “3M” methodology to obtain superhydrophobic PDMS-based materials for antifouling applications

“…One-dimensional nanoparticles can exhibit nanorod ( Selim et al, 2019 ; Selim et al, 2022a ; Selim et al, 2022b ), nanowire ( Zhang et al, 2013 ; Li et al, 2020 ), nanofilament ( Zhou et al, 2022 ), nanotube ( Wang et al, 2010 ), and nanofiber structures ( Chen et al, 2009 ; Liang et al, 2020 ), among other morphologies. Mohamed S. Selim et al fabricated a superhydrophobic nanocoating based on PDMS and ZnO nanorods; the coating exhibited long-term antifouling abilities for marine applications ( Selim et al, 2019 ).…”