Facile Creation of a Super‐Amphiphobic Coating Surface with Bionic Microstructure

Abstract

In nature, there are vast singular structures or morphologies on biological surfaces that exhibit super-water-repellent properties. [1,2] The two-length-scaled hierarchical structure of the surface of the sacred lotus leaf is a good example. [3] In the meantime, the wetting ability of liquids on solid surfaces has become very important in daily life as well as in many industrial processes. Super-hydrophobic surfaces and super-amphiphobic surfacesÐi.e., surfaces that exhibit both water-repellent and oil-repellent propertiesÐhave attracted much interest because of potential practical applications.[4] Previous works on obtaining super-hydrophobic or super-amphiphobic surfaces have often used a combination of depressed surface energy and enhanced surface roughness.[4±16] However, the strict preparation conditions, multi-step processes, limited applicability, and high cost of the previous methods made forming large-area super-hydrophobic surfaces in ambient atmosphere for applications very difficult. Hence real applications of such super-hydrophobic or super-amphiphobic surfaces have been very limited. We describe in this communication a simple one-step casting process for creating a super-amphiphobic polymeric coating from two easily synthesized or commonly available polymer materialsÐpoly(methyl methacrylate) (PMMA) and fluorine-end-capped polyurethane (FPU)Ðin air without further modification. It is very exciting that such a polymer coating exhibits super-hydrophobic and lypophobic properties. The study also shows that the polymer surface possesses natural lotus-like micro-and nano-hierarchical structure. Our method reveals the possibility of one-step preparation of a super-hydrophobic polymer surface utilizing the difference in solubility of two common polymers in a solvent. We believe that this is the first report of creating a super-hydrophobic surface with such a simple casting process under ambient atmosphere.The scanning electron microscopy (SEM) images of the synthesized polymer surfaces are shown in Figure 1. No obvious structures were observed by SEM for the pure FPUcoated surface (Fig. 1a). The contact angle (CA) on the surface is about 95 (Fig. 2a), which indicates that FPU film has better hydrophobicity than pure polyurethane without the fluorine group, whose CA is about 65. The pure PMMA surface (Figs. 1b,c) is rough and the water CA on it is relatively high (145, Fig. 2b). However, the water drop is pinned on the PMMA surface. It is interesting that the hydrophobicity of the polymer surface changes dramatically if the film is directly prepared by a one-step coating of a FPU/PMMA mixture solution between 10 and 40 C. The CA increases to 166 (Fig. 2c).We also use sliding angle (SA) as a criterion for the evaluation of hydrophobicity of a solid surface. SA is a measure of the sliding properties of water droplets on the surface and is also considered an important property in deciding the superhydrophobicity. [17,18] Figure 3a shows that SA can be dramatically decreased with a small amount of FPU, reaching...

Recent developments in polymeric superoleophobic surfaces

“…in which f is the fraction of the solid/liquid interface, while (1 À f) is that of the air/liquid interface, indicates that, when a rough surface, which possesses nano structures 30 or micro/nano hierarchical structures, 33 comes into contact with liquid, air may be trapped in the rough area. The trapped air layer will contribute greatly to repel the liquid.…”

“…107 Other Methods One-Step Casting Process Utilizing Difference in Solubility of Polymers Xie et al reported a superoleophobic PMMA and fluorineend-capped polyurethane film. 33 This film was fabricated by utilizing difference in solubility of the two polymers in one solvent. The SEM image showed the polymer surfaces possess natural lotus-like micro/nano structures [ Fig.…”

“…From then on, the study of superoleophobicity aroused with broad interest. In 2001 and 2004, our group reported nanostructured aligned carbon nanotube (ACNT) films 30 and micro/nano hierarchically structured polymer surfaces 33 with excellent superoleophobicity, respectively. Those studies revealed the significance of nanostructures and micro/nano hierarchical structures for constructing superoleophobic surfaces.…”

Superhydrophobic cotton fabrics prepared by sol–gel coating of TiO2and surface hydrophobization

“…In recent years, researchers have made impressive efforts to prepare superhydrophobic surfaces for potential applications in a variety of areas [1][2][3][4][5][6][7][8]. Among others, superhydrophobic textiles have been successfully obtained by a number of different approaches [9][10][11][12][13][14][15][16].…”

Numerical Control Device for Preparation Nano-Carbon Granule Coating Superhydrophobic Template and Its Application

“…No natural surface can show that it is greater than 150° of the static contact angle and below 10° of the rolling angle at the same time for water and organic liquid. Such surface is superhydrophobic and superoleophobic [13,14].…”