Multistimuli‐Responsive Insect‐Scale Soft Robotics Based on Anisotropic Super‐Aligned VO₂ Nanowire/Carbon Nanotube Bimorph Actuators

Abstract

The emerging soft robots have attracted increasing interests and gotten rapidly developed, but it is still challenging to substantially promote their response speed and work density. In addition, the wireless way to conveniently trigger the devices, especially for the centimeter‐scale ones, is highly desired. Herein, the multistimuli‐responsive insect‐scale soft robotics is reported based on a super‐aligned VO2 nanowire arrays (NAs)/carbon nanotube (CNT) bimorph film, comprehensively addressing aforementioned problems. The as‐prepared VO2 NA/CNT bimorph shows improved actuation performance, anisotropic behavior, rapid response to various stimuli (heat, light, and electricity), and multiple movement modes (bending and torsion). Consequently, diverse untethered, insect‐scale soft robots, serving as biomimetic crawler, lifter, gripper, wing of flying robots, torsional robot, and so on are successfully demonstrated. The findings provide an effective strategy to develop high‐performance macroscopic mechanical devices by assembling functional nanostructures.

Fabrication of Moisture-Responsive Crystalline Smart Materials for Water Harvesting and Electricity Transduction

“…Developing moisture-based energy-harvesting technologies has attracted extensive and intense attention attributed to its great application potential in both energy-related − and wearable electronics fields. ,, The key to achieving energy transduction depends on using advanced materials as the media . Smart materials, as a new generation of advanced materials, can undergo a reversible property change by external stimuli, such as heat, − electricity, , light, − magnetism, , and moisture. ,, Recently, moisture-responsive smart materials have attracted widespread interest. As pioneering works, many efforts had been made to fabricate humidity-sensitive devices based on smart materials, including cellulose nanofibers, , poly pyrrole, ,, graphene, ,− carbon nanotubes, poly dopamine, supramolecular crystals, and so on. , Anisotropic and reversible absorption–desorption of water vapor by these actuators resulted in an impressive mechanical response.…”

Advances in Stimuli-Responsive Soft Robots with Integrated Hybrid Materials

“…To enhance the electrothermal and optical properties, various nanowire additives have been extensively adapted to manufacture stimuli-responsive shape-changing soft machines [29][30][31][32][33][34][35][36][37]. The nanowires can absorb a certain wavelength of light, which transfers to thermal energy, allowing the shape transformation of thermally responsive soft machines.…”

“…(F) Multi-stimuliresponsive soft gripper using vanadium dioxide (VO2) nanowires and carbon nanotube composites. Reproduced with permission [34], adapted with permission under the terms of the Creative Commons Attribution Non Commercial License 4.0, copyright 2020, the authors. Innovative trials have been conducted using living additives directly combined with metallic or ceramic materials, which exploit new concepts of biological actuators or electric generators.…”

“…This multi-responsive actuator displayed a reversible operation, which responded fast (<5 s), and highly synchronized flexible actuators driven by the pseudo-capacitance-based reversible lattice contraction/recovery process of W 18 O 49 nanowires. Chen et al proposed a multi-stimuli-responsive soft robot using a vanadium dioxide (VO 2 ) nanowire ( Figure 1F) [34]. In particular, they designed an insect-scale gripper consisting of super aligned VO 2 nanowires and a carbon nanotube (CNT) bimorph composite film that was actuated by various stimuli such as heat, light, and electricity.…”

Small‐Scale Soft Robot with High Speed and Load Capacity Inspired by Kangaroo Hopping

“…[1][2][3][4][5][6] Therefore, the driving method of small robots should include features such as fast response, large driving force, and high energy storage. Existing driving methods use piezoelectric, [2,7] dielectric, [8][9][10] pneumatic, [11,12] humidity, [3,13] thermal, [14,15] or light [16,17] power sources, among others. Small robots using these driving methods cannot fully satisfy the requirements for practical utilization because of poor load capacity, slow running speed, high driving voltage, [7][8][9][10] low energy density, [13,14,17] and inability to eliminate air sources.…”