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Optical functional surfaces are key components of nearly every optical device and they have become a special focus in both academia and industry. The no contact, one step, direct, and maskless laser surface texturing technique is one of the most encouraging approaches for realizing the surface functions. We use a high power and high repetition rate ultrafast laser system to produce micro–nano structures on metal surfaces. We demonstrate that metal surface micro–nano structures and correspondingly their optical responses can be facilely tailored by simple controlling the ultrafast laser processing parameters. Nano particles of tens to hundreds nm, sub-micro particles of 0.5–1 μm, fine-micro particles of 1–10 μm, micro particles of 10–50 μm, and coarse-micro particles larger than 50 μm have been fabricated on Cu surfaces. And surface reflection of copper surfaces has been tuned from 10% to 90% in spectra level and from UV to MIR in spectrum range, with unique optical properties like visible selective reflection, linear changing reflection, band reflection, and broadband absorption being achieved. The formation processes of those particle structures as well as the underlying mechanisms for their optical responses are discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Superhydrophobic and colorful copper surfaces were fabricated by picosecond laser nanostructuring. [•] The effects of laser processing parameters on the LIPSS formation were discussed. [•] The laser nanostructured surfaces exhibited different adhesive forces to water. [•] Some of the laser nanostructured surfaces presented a superhydrophobic behavior. [ABSTRACT FROM AUTHOR]

Abstract: We report the investigations on structural modifications in monolayer graphene induced by low-power-density CO2 laser irradiation (2–60W/cm2). Observed modifications in graphene include the disassembly of crystalline graphene into nanocrystalline structure and the generation of amorphous carbon. It was found that thermal effect played an important role during laser irradiation. By adjusting laser power density, irradiation time and temperature, the structure of graphene can be modified accordingly in a controlled manner. Our approach may enable high-efficiency and economical modification of large-area graphene, which relies on large-area irradiation using low-power-density laser. [Copyright &y& Elsevier]

Abstract: Fabrication of nanoporous Cu–Mn alloy coatings was investigated by a two-step process involving high power laser cladding of a homogeneous Cu40Mn60 alloy coatings followed by selectively electrochemical de-alloying. Auger mapping results indicate that nanoporous manganese was obtained by selective electrochemical etching of the less active Cu component owing to the passivation of the more active manganese in potassium nitrate solution. The surface morphology of the porous Mn was a ribbon-like structure, different from interconnected bicontinuous nanopores that are usually obtained by de-alloying. The influence of de-alloying time, electric potential and temperature on the formation of nanoprosity is systematically investigated. Nanopore sizes can be tailored to be less than 100nm. Under optimal etching conditions the nanopore size was below 25nm. The surface area of the nanoporous manganese layer was enhanced by up to 990 times compared with that of a polished sample. [ABSTRACT FROM AUTHOR]

The capabilities to reduce light reflection have essential importance for various critical applications. Realistic antireflection surfaces are required to satisfy the comprehensive demands in broadband effectiveness, flexible fabrication, and performance stability. Here, we propose and experimentally demonstrate a type of highly disordered hyper-hierarchical micro-nano structures formed on the surfaces of metals such as Cu, which have the significant capability in absorbing light over the ultrabroadband spectrum from ultraviolet to far-infrared. Average hemispherical reflectance of ∼2.4%, ∼5.5%, and ∼6% is achieved in the wavelength ranges of 400–800 nm, 200–2000 nm, and 2.5–25 μm, respectively, reaching an average absorptance of ∼94% within 0.2–25 μm. The specular reflectance in the long wavelength range of 25–300 μm is also dramatically reduced with respect to the original Cu surface. Such an ultrabroadband antireflection structure is fabricated by a non-contact, maskless, one-step femtosecond laser direct writing approach, making it flexible to be prepared in desired patterns. The hyper-hierarchical structure and its ultrabroadband antireflection property keep robust and stable during harsh aging tests. In addition to the antireflection property, the hyper-hierarchical structure also exhibits excellent self-cleaning performance. All these advantages in ultrabroadband effectiveness, patterning flexibility, structural robustness, as well as self-cleaning, make it promising for practical applications. [ABSTRACT FROM AUTHOR]

The potential applications of superamphiphobic surfaces are widespread and attractive. The design of re-entrant structures is crucial to superamphiphobic surfaces. However, both the existing two strategies to design re-entrant structures face problems. Here a creative strategy to design 3D re-entrant nanostructures on ordered microstructures is proposed. A novel “Top-down” and “Bottom-up” hybrid method consisting of ultrafast laser ablation and chemical bath processing is used to fabricate hierarchical surfaces with 3D re-entrant CuO nanograss on Cu microcones. Thanks to the low surface energy from modification with perfluorodecyltrimethoxysilane and plenty of re-entrant geometries provided by the 3D distributed nanograss structures, the hierarchical surfaces show outstanding superamphiphobicity with water and low surface tension liquid like dodecane. The influence of the nanograss types and the microcone distribution on the superamphiphobicity are systematically studied. Besides, the microcones/nanograss hierarchical superamphiphobic surfaces show excellent long-term durability, high temperature durability and comprehensive mechanical durability, are promising for practically applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabricated an environmentally adapted slippery-superhydrophobic switchable surface. • The constructed surfaces spontaneously adapted to various icing environments. • The constructed surfaces combined anti-ice-pinning and anti-water-pressure properties with durable switchability. • The surface is facilely and large-scale fabricated, showing great potential for practical applications. Numerous state-of-the-art anti-icing surfaces have been developed to avoid undesired icing. However, they generally only work in the single static icing occasion. Under dynamic disturbances, the unstable interfacial states could fail easily, leading to the loss of icephobicity. The impalement of air interfaces on superhydrophobic surfaces and liquids captured by lubricant interfaces are two most known failure mechanisms. How to address these problems and develop a surface with adaptability to changeable harsh environments is of great challenge but of high value. Here we analyze the effects of structural sizes on surface resistance forces and slippery durability and propose a structural design method to balance their relationship. Adopting the optimized structures, we fabricate an environmentally adapted slippery-superhydrophobic switchable surface, which reversibly switches interface states to maintain low adhesion in different environments. We demonstrate that the surfaces show excellent slippery anti-icing properties in static environments and overcome impalement issues. Even in extreme low-temperature environments, a photothermal-assisted droplet self-dislodging is realized. Confronting dynamic disturbances, the superhydrophobic interfaces are spontaneously activated with the broadened anti-water-impact ability (up to 200 kPa). A series of experiments confirm the long-term anti-icing, switchability and universality of our constructed surfaces, which could accelerate practical anti-icing applications in many related fields. [ABSTRACT FROM AUTHOR]

We report here a simple and efficient hot embossing process capable of mass fabricating superhydrophobic and self-cleaning polytetrafluoroethylene (PTFE) film surfaces. Adding superhydrophobicity to hydrophobic polytetrafluoroethylene (PTFE) significantly enhances their application potential in industry as well as in daily life. We applied a picosecond laser to fabricate regular array of micro-holes companied with submicron structures on high strength steel substrate to form a lotus-leaf-like template. Then the hot embossing process was performed on flat PTFE films to introduce a dual-scale structure composed of the micro-scale protrusions and nano-scale fibril structures on the top of protrusions. The hot embossing parameters such as the embossing pressure and time were optimized to achieve required micro- and nano-scale dual structure on PTFE film very closed to the similar dual structure of the lotus leaf surface. The PTFE films then exhibited superhydrophobicity with contact angle up to 154.6° and sliding angle of as low as 5.5°. The thermal stability of the superhydrophobic PTFE films was investigated from room temperature up to 430 °C. We demonstrate that the micro–nano dual structure on PTFE films and their superhydrophobicity is thermally stable up to 340 °C. The micro-scale protrusions will collapse and the superhydrophobicity will lose when the temperate is over 370 °C. [ABSTRACT FROM AUTHOR]