Femtosecond laser direct writing of functional stimulus-responsive structures and applications

Abstract

Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment. Inspired by nature, researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate. Among many fabrication methods for stimulus-responsive structures, femtosecond laser direct writing (FsLDW) has received increasing attention because of its high precision, simplicity, true three-dimensional machining ability, and wide applicability to almost all materials. This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW. Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies, different stimulating factors that can trigger structural responses of prepared intelligent structures, such as magnetic field, light, temperature, pH, and humidity, are emphatically summarized. Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW, as well as the present obstacles and forthcoming development opportunities, are discussed.

Femtosecond laser ultrafast photothermal exsolution

“…Employing higher power lasers accompanied by further increasing scan speed to m•s −1 can make this technique more efficient and practical for industrial applications, rather than being limited in the lab-scale. From material perspective, black and darkblue ZrO 2 can also be potentially applied as solar absorbers [24,52], pigments and dyes [53], and in decoration, implant dentistry [54], photocatalyst [55] fields; while from technique perspective, the applications of our method is as well compatible with those of fs laser ablation/structuring, patterning, and material synthesis within the scope of optics/photonics [56][57][58][59][60][61], energy [62], photoelectronic [63], flexible electronics [64], wettability [65,66], biomimetic [67], bubble/gas manipulation [68], stimulus-responsive interfaces [69], miniaturized robotics [70], fundamental studies [71][72][73][74], etc.…”

Triboelectric ‘electrostatic tweezers’ for manipulating droplets on lubricated slippery surfaces prepared by femtosecond laser processing

“…A polydimethylsiloxane (PDMS) sheet with a thickness of 1 mm was chosen as the substrate because of its intrinsic hydrophobicity and excellent compatibility with silicone oils (the most commonly used lubricant). The characteristics of ultrashort pulse width and ultrahigh peak power have made femtosecond (10 −15 s) lasers one of the most important tools in modern extreme and ultraprecision manufacturing [48][49][50][51][52]. Femtosecond laser processing was utilized to create the required microstructures on the PDMS surface, as shown in figure S2 (supporting information).…”

Efficient concentration of trace analyte with ordered hotspot construction for a robust and sensitive SERS platform

“…The AAO template has a thickness of 125 nm, a pore diameter of 70 nm and a pitch of 100 nm, as shown in figure S1. First, the femtosecond laser is adopted to process the 2D grid pattern on the AAO template to form a linear microgroove array by the line-scanning method [28][29][30]. Then, poly(methyl methacrylate) (PMMA) solution, prepared by dissolving the PMMA powder into toluene, is drop-coated onto the surface of the grooved template.…”