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Functional surfaces with broadband ultralow optical reflectance have many potential applications in the fields of enhancing solar energy utilization, stray light shielding, infrared stealth, and so on. To fabricate broadband anti-reflection surfaces with low cost, high quality, and more controllability, a strategy of preparing multi-scale structures by thermal-assisted nanosecond laser was proposed. This strategy combines laser ablation with Marangoni flow of molten materials and in situ deposition of nanoparticles. The thermal-assisted strategy increases the depth to width ratio of the anti-reflection structures. The average reflectance of laser-textured TC4 (Ti-6Al-4V) surface is as low as 1.71% in the wavelength range of 200–2250 nm and 7.8% in the 2500–25,000 nm. The ultra-low reflectance surface has a significantly enhanced photothermal conversion performance. Meanwhile, the anti-reflection effect can be extended to the mid-infrared band, which has potential stealth application prospect. This synergetic manufacturing strategy has wide adaptability of materials, which provides new paths for the preparation of broadband ultralow reflectance surface. Moreover, this thermal-assisted laser fabrication strategy is prospective in the preparation of other functional micro-nano structures. [ABSTRACT FROM AUTHOR]

The poor wear performance of passive anti-icing micro/nano-structured TC4 surface restricts its wide applications in engineering field. Interestingly, it was observed that microstructure of sled dog hair exhibits a low-temperature-adaptive property to keep away from ice accumulation by the perforations located in the center of the hair shaft and the cuticle of lobster claw reveals extraordinary mechanical strength with micro-porous structures. In this work, bioinspired top-perforated micro-conical array structure is proposed on TC4 surfaces compatible with anti-icing property and mechanical durability. The microstructured unit is composed of a micro-conical frustum and a perforated micro-hole on the top, which could be fabricated on TC4 via direct nanosecond ultraviolet laser processing. The delayed freezing time of the water droplet on the bioinspired surface can be significantly extended by 18 times, exhibiting excellent superhydrophobicity with WCAs exceeding 164°. Meanwhile, the bioinspired anti-icing surface shows excellent wear resistance by both abrasion and water impinging tests, where the delayed freezing time does not obviously decrease after 30 mins' continuous water impinging. The top-perforation of the micro-conical could enhance the anti-icing property and durability simultaneously and the results were explained based on finite element analysis. The proposed bioinspired TC4 structure fabricated by pulsed laser ablation has great engineering potentials in extremely cold and humid environments. [ABSTRACT FROM AUTHOR]

The fabrication of bionic surfaces resembling hydrophobic plants through micro manufacturing, which creates abundant multi-level micro/nanostructures and elemental variations, has been widely employed to change the surface wettability of metallic materials. Based on the mechanisms for selective permeation of various liquids, it could achieve the function of oil/water separation. Herein, a separation copper membrane fabricated with pulsed laser ablation and modified with graphene oxide (GO) deposition showed a synergetic effect on tunable surface wettability. Micro/nanostructures were generated on the copper substrate membrane through concentric circular scanning, which was followed by hole drilling. Afterwards, charged GO nanosheets were deposited via electrophoresis. The spacing of circular lines, the diameter of the holes and the abundant high-surface-energy hydrophilic oxygen contained in deposited GO amounts could be regulated in the laser processing and deposition, resulting in oleophobicity and hydrophilicity at the same time. The highest contact angle of oil in water of the prepared mesh could reach above 165° with a hole size of 200 µm and a circular line spacing of 100 µm after the laser processing. Water flux and oil-holding capacity, which represent the separation capability of the mesh, were also evaluated. The as-prepared separation mesh also showed great stability under harsh environments. [ABSTRACT FROM AUTHOR]