Ingenious humidity-powered micro-worm with asymmetric biped from single hydrogel

A fine single Pd microwire H2 sensor fabricated by using a femtosecond laser for a wide detection range at room temperature

“…2a shows the schematic diagram of a SPM sensor fabricated by femtosecond laser processing, which was proved to be an efficient method for micro-nano scale devices. [31][32][33][34][35][36] Here, the laser beam with a certain power is guided by the light path and radiated on the interface between the electrode and the PdNP droplet. The patterned PdNPs were prepared by controlling the scanning path of the 3D processing platform.…”

Development and challenges of smart actuators based on water-responsive materials

“…In recent years, a variety of hydrogels have been developed for actuation studies, including the poly(e-caprolactone)-agarose hydrogel, 88 alginate hydrogel, 94,95 hydroxypropyl methylcellulose hydrogel, 96 polyacrylamide hydrogel, 87,97 poly(acrylic acid) hydrogel, 33,98 poly(N-isopropyl acrylamide) hydrogel, 99 poly(N-alkylacrylamide) hydrogels, 100 and poly(ethylene glycol) diacrylate (PEG-DA) hydrogel. 93,101,102 Taking advantage of the hygroscopic properties of polymer hydrogels, a variety of actuation applications can be realized. For example, inspired by the hygroscopic movement of plant awns and waterfowl beak structures, Ma et al integrated poly(acrylic acid) hydrogel, cellulose membrane, and superhydrophilic copper wire to fabricate a smart WR switch to control the directional transport of a droplet.…”

“…Reproduced with permission. 93 Copyright 2020, Elsevier. (e) The ratchet robot relies on a spatial humidity gradient to move.…”

A Humidity-Powered Soft Robot with Fast Rolling Locomotion

“…To address this challenge, we focus on humidity-responsive materials, which can convert the energy from ambient evaporation into mechanical energy and thus have attracted increasing attentions to be used in humidity-driven actuators. Such materials include polymer gels [ 35 – 37 ], elastomers [ 38 ], shape memory polymers [ 39 , 40 ], carbon nanomaterials [ 41 ], and electroactive polymers [ 42 ]. For application as actuators, humidity-responsive materials must provide fast water absorption and desorption.…”