Superomniphobic and Easily Repairable Coatings on Copper Substrates Based on Simple Immersion or Spray Processes

Abstract

Textures that resemble typical fern or bracken plant species (dendrite structures) were fabricated for liquid repellency by dipping copper substrates in a single-step process in solutions containing AgNO3 or by a simple spray liquid application. Superhydrophobic surfaces were produced using a solution containing AgNO3 and trimethoxypropylsilane (TMPSi), and superomniphobic surfaces were produced by a two-step procedure, immersing the copper substrate in a AgNO3 solution and, after that, in a solution containing 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES). The simple functionalization processes can also be used when the superomniphobic surfaces were destroyed by mechanical stress. By immersion of the wrecked surfaces in the above solutions or by the spray method and soft heating, the copper substrates could be easily repaired, regenerating the surfaces' superrepellency to liquids. The micro- and nanoroughness structures generated on copper surfaces by the deposition of silver dendrites functionalized with TMPSi presented apparent contact angles greater than 150° with a contact angle hysteresis lower than 10° when water was used as the test liquid. To avoid total wettability with very low surface tension liquids, such as rapeseed oil and hexadecane, a thin perfluorinated coating of poly(tetrafluoroethylene) (PTFE), produced by physical vapor deposition, was used. A more efficient perfluorinated coating was obtained when PFDTES was used. The superomniphobic surfaces produced apparent contact angles above 150° with all of the tested liquids, including hexadecane, although the contact angle hysteresis with this liquid was above 10°. The coupling of dendritic structures with TMPSi/PTFE or directly by PFDTES coatings was responsible for the superrepellency of the as-prepared surfaces. These simple, fast, and reliable procedures allow the large area, and cost-effective scale fabrication of superrepellent surfaces on copper substrates for various industrial applications with the advantage of easy recovery of the surface repellency after damage.

Bioinspired Superwettability Micro/Nanoarchitectures: Fabrications and Applications

“…The dip‐coating method, also known as the solution‐immersion process, involves immersing a substrate in a solution to create roughness ( Figure a) . By immersing a copper substrate in a fatty acid solution, the substrate can be covered by flower‐like clusters of Cu(CH 3 (CH 2 ) 12 COO) 2 (Figure b), which possess a large water contact angle and small sliding angle; dipping a copper substrate in a AgNO 3 solution or ammonia solution at 5 °C for 36 h and then treating the substrates with fluorinating agents, result in omniphobic surfaces (Figure c) with silver dendritic structures or copper hydroxide nanoneedle arrays (Figure d), respectively. Alternatively, aqueous suspensions containing low‐surface‐energy fluorocarbon surfactants and nanoparticles, such as TiO 2 , SiO 2 , or Al 2 O 3 nanoparticles, can also be used as dipping solutions to obtain superwettability .…”

“…c) Surface fabricated by dip coating; the inset shows the contact angle of a hexadecane drop on the surface. Reproduced with permission . Copyright 2015, American Chemical Society.…”

Chemical and Physical Pathways for Fabricating Flexible Superamphiphobic Surfaces with High Transparency

“…However, a rougher surface tends to have a lower transparency. Surfaces that are highly transparent, flexible, and superamphiphobic requires an optimized surface roughness that can trap air underneath (Cassie-Baxter state) and a passivation layer with a low surface energy coated Engineering transparent surfaces that actively repel water [34], oil [35], low-surface-tension liquids [36], and/or organic liquids have many applications in the fields of fluids [37,38], chemical shielding [39], stain-proof coatings [40,41], membrane technologies [42], and antifouling coatings [43]. During the past decade, superhydrophobic surfaces have received much attention because of the challenge of understanding their basis [1,[44][45][46] and the many technological implications they possess [47][48][49][50][51].…”

Facile fabrication of amphiphobic surfaces on copper substrates with a mixed modified solution

“…The hydrophilicity and oleophilicity of most metals, such as copper, limit their application in many special environments. 1 Superhydrophobic surfaces have been fabricated on copper substrates by etching, 2-5 electrodeposition, [6][7][8] femtosecond laser, 9,10 etc., which can repel water but lack oleophobicity at the same time, resulting in the surfaces being readily polluted by low surface energy oils. 11,12 Transforming the amphiphilicity of copper substrates to amphiphobicity can avoid oil and water contamination.…”