Fabrication Of Superhydrophilic Surfaces Research Articles

Fabrication of super hydrophilic surface on FeCrAl-WM with ridged microstructure for Joule-heating catalyst support by UV-laser microprocessing

The catalyst support with super hydrophilic surface facilitates uniform loading and firm adhesion of the catalyst. In this paper, ridged microstructures were fabricated on the surface of FeCrAl wire mesh (FeCrAl-WM) by UV-laser processing. The mechanism behind the formation of ridged microstructures was elucidated. The influence of scanning interval on the stacking and separation of recast layers was analyzed. The effects of laser processing parameters on surface roughness and hydrophilicity of FeCrAl-WM surface with ridged microstructures were investigated. By adjusting laser processing parameters, it is possible to regulate both the roughness factor and oxygen content of the FeCrAl-WM surface, thereby controlling its hydrophilicity and varying contact angles between 0° and 90°. Catalyst loading experiments were conducted on FeCrAl-WM after laser processing, followed by testing the performance of MSR microreactor for hydrogen production using FeCrAl-WM as a catalyst support material. At an inlet flow rate of 4 ml/h at 280 °C, a maximum hydrogen production rate of 0.21 mol/h was achieved with a methanol conversion rate reaching 91.5 %. We envision that the laser microprocessing offers a convenient and effective approach to develop super hydrophilic surface on FeCrAl-WM materials for use as Joule-heating catalyst support.

Fabrication of super hydrophilic surface on alumina ceramic by ultrafast laser microprocessing

In this research, super hydrophilic surface on the alumina ceramic substrate is fabricated by ultrafast laser microprocessing. The laser textured surface developed by femtosecond laser in the air atmosphere is able to maintain the super hydrophilic property for 36 h and still remains hydrophilic with the contact angle of 57.9°after 240 h. Surface morphology and chemical composition of the laser textured surface are characterized by scanning electron microscope (SEM), 3D laser scanning confocal microscope (LSCM) and X-ray photoelectron spectroscope (XPS). Results show that femtosecond laser can provide larger surface roughness in contrast with picosecond laser. Laser microprocessing can also increase the content of oxygen element and polar functional groups on the surface of the alumina ceramic substrates. Furthermore, the mechanism of the hydrophilic behavior of droplets on the laser textured surface is discussed in details and it is noted that surface morphology plays a leading role in amplifying the inherent wettability. We envision that the laser microprocessing provides a facile and effective route to develop long-term super hydrophilic surface on alumina ceramic materials.

Erratum: “Fabrication of superhydrophilic surface on metallic nickel by sub-nanosecond laser-induced ablation” [AIP Adv. 9, 085308 (2019)

Erratum: “Fabrication of superhydrophilic surface on metallic nickel by sub-nanosecond laser-induced ablation” [AIP Adv. 9, 085308 (2019)

Fabrication of superhydrophilic surface on metallic nickel by sub-nanosecond laser-induced ablation

The alterations of wettability on metallic nickel surface by sub-nanosecond laser (1 ns, 1064 nm) induced surface modification was investigated. An approximate linear relation between surface contact angles (CAs) and accumulated fluence was established, which shows that with proper combinations of laser parameters, CA would reduce significantly from its initial value (∼96°) to approximately 3.1°. The microscopic inspection and roughness test reveal that the surface roughness on irradiated areas would increase remarkably due to the distribution of micro/nanoparticels and cracks that induced by laser ablation, which consequently improve the hydrophilic performance effectively. On the other hand, elemental analyses by use of XPS demonstrate that the nickel dioxides and nickel hydroxides were generated as the main components covering the self-organized structures. Such increasement in oxygen content, especially the growth of NiO and hydroxyl group provides a prerequisite in the transformation of nickel from initial hydrophobicity to hydrophilicity. And the integrated effects of surface morphology, roughness and chemistry ultimately led to the formation of super-wettability. The investigation indicates that, the sub-nanosecond laser is an effective tool to transform the metallic nickel into functional material with a highly hydrophilic surface by creating controllable topographical features and chemical properties on its surface.

Fabrication of superhydrophilic surface on copper substrate by electrochemical deposition and sintering process

Superhydrophilic surfaces were fabricated on copper substrates by an electrochemical deposition and sintering process. Superhydrophobic surfaces were prepared by constructing micro/nano-structure on copper substrates through an electrochemical deposition method. Conversion from superhydrophobic to superhydrophilic was obtained via a suitable sintering process. After reduction sintering, the contact angle of the superhydrophilic surfaces changed from 155° to 0°. The scanning electron microscope (SEM) images show that the morphology of superhydrophobic and superhydrophilic surfaces looks like corals and cells respectively. The chemical composition and crystal structure of these surfaces were examined using energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The results show that the main components on superhydrophobic surfaces are Cu, Cu2O and CuO, while the superhydrophilic surfaces are composed of Cu merely. The crystal structure is more inerratic and the grain size becomes bigger after the sintering. The interfacial strength of the superhydrophilic surfaces was investigated, showing that the interfacial strength between superhydrophilic layer and copper substrate is considerably high.

Anisotropic growth of Ni3(BO3)2 nanowhiskers on nickel substrates and its application in the fabrication of superhydrophilic surfaces

One-dimensional single-crystalline Ni3(BO3)2 nanowhiskers were grown on Ni substrates using molten-salt method in air with MnO2 as the agent.