Hybrid Nanosecond Laser Processing and Heat Treatment for Rapid Preparation of Super-Hydrophobic Copper Surface

Abstract

The super-hydrophobic copper surface was obtained by using a nanosecond pulsed laser. Different micro-and nano-structures were fabricated by changing the laser scanning interval and scanning speed, before heating in an electric heater at 150 • C for two hours to explore the effect of laser parameters and heat treatment on the wettability of the copper surface. It was found that the laser-treated copper surface is super-hydrophilic, and then, after the heat treatment, the surface switches to hydrophobic or even super-hydrophobic. The best super-hydrophobic surface's apparent contact angle (APCA) was 155.6 • , and the water sliding angle (WSA) was 4 • . Super-hydrophobic copper is corrosion-resistant, self-cleaning, and dust-proof, and can be widely used in various mechanical devices.In order to find the best super-hydrophobic metal surface, we should know the reasons behind certain materials being super-hydrophobic.A dense column micro-or nano-structure is the key factor causing a super-hydrophobic surface. Thus, when we look for a super-hydrophobic surface, micro-and nano-scale dense column structures, such as the microstructures of lotus leaves, bird feathers, and butterfly wings, are considered. Although there are many ways to fabricate the hybrid micro/nano-structure on the material surface, such as chemical vapor deposition, chemical etching, nano-imprint lithography, electrode position, etc., there are various problems in their application [8][9][10][11][12][13][14][15][16][17]. For example, the size of the micro/nano-structure formed by the chemical etching method is very sensitive to external conditions such as temperature and concentration of chemical solution. In addition, etching reagents are mostly corrosive reagents with safety and environmental issues. Unlike the above methods, lasers can fabricate and precisely control the size of micro/nano-structures [18][19][20][21][22][23]. Therefore, laser processing can be used to quickly obtain micro/nano-structures. Recent studies found that the surfaces of metal oxides and nanostructures formed by laser ablation are initially hydrophilic or even super-hydrophilic; however, over time, they become hydrophobic, and sometimes even super-hydrophobic in air after two weeks to two months [24]. Several mechanisms were proposed to explain this phenomenon. Chang et al. proposed that the deoxidation of copper oxide could effectively promote the development from a hydrophilic to a super-hydrophobic surface [25,26]. Boinovich et al. believed that metal oxides adsorbed organics in the air, resulting in the transition from a super-hydrophilic to super-hydrophobic surface [27,28]. It can be seen that, although most researchers extensively studied this topic, there is obvious controversy regarding the mechanism of the wettability transition behavior.In this paper, a rapid method of fabricating a super-hydrophobic surface on a copper plate was studied. Micro/nano-structures were fabricated on copper surfaces by laser ablation, which then became super-hydrophobic after heat t...

Rapid laser fabrication of long-term stable superhydrophilic aluminum surface

“…Therefore, it can be inferred that the striated micron structure formed by laser ablation improves the hydrophilic energy of the surface and even converts to superhydrophilic [18]. This is consistent with the morphological characteristics of aluminum sheet processed by nanosecond laser by Zhao team [15].…”

“…As a precision machining tool, laser has the advantages of high power density and controllable machining precision. It is a convenient, fast and controllable method to produce metal-based superhydrophilic surfaces [12][13][14][15]. Some researchers have proposed a method to prepare superhydrophilic surface by laser etching aluminum surface.…”

Thermally Induced Gradient of Properties on a Superhydrophobic Magnesium Alloy Surface

“…As it was clearly demonstrated in recent literature [5,6], laser surface texturing has emerged as powerful and versatile nanotechnology for producing surfaces with hierarchical roughness and high curvature of textural elements. Such roughness, required for obtaining the superhydrophobic state of materials, allows making an important step for the development of new materials for protection against icing and corrosion, fouling and bacterial contaminations [7][8][9][10][11][12][13][14][15][16].…”

Copper Corrosion Behavior in Simulated Concrete-Pore Solutions

“…it is considered that Cu 2 O oxide (1) is insoluble in water and is a hydrophobic substance, factors which affect to a certain extent the interaction of polar water molecules with the surface [13]. The cathodic reaction involves the reduction of oxygen, the diffusion of which through the oxide layer controls the corrosion process [11]:…”

“…The model solutions allow comparative results to be obtained, and control of some testing parameters, which are difficult to achieve with concrete samples, mainly not homogeneous in their internal surface. Many model solutions have been proposed, including the use of a saturated aqueous solution of Ca(OH) 2 (pH [12][13] [14,16,18,[20][21][22][23], aqueous KOH and NaOH [24][25][26][27], and cement extract solution [11,16,28,29]. The most commonly reported model is the saturated Ca(OH) 2 solution.…”