Tunable Photothermal Actuators Based on a Pre-programmed Aligned Nanostructure

Abstract

For various applications, it is challenging but essential to obtain complex tunable mechanical actuations in response to environmental stimuli. Here, a general and effective strategy is developed to produce multiple types of photomechanical actuation (from phototropic/apheliotropic bending to three-dimensional helical buckling) by manipulating the orientation of one-dimensional nanomaterials. These materials are manipulated to mimic plants that generate diverse mechanical motions through the orientation of cellulose fibrils. The photomechanical actuations can be completed in milliseconds and can be performed reversibly without detectable fatigue after 100 000 cycles. This capacity to produce multiple types of photomechanical actuation is further developed to produce complex integrated movements, as demonstrated by a light-manipulated robotic arm and a solar energy harvesting system.

High‐Power Actuation from Molecular Photoswitches in Enantiomerically Paired Soft Springs

“…The variety of movements seen in the plant and animal kingdoms have provided inspiration for the engineering of soft robots of all kinds,9, 10, 11, 12, 13, 14 and in particular, the realization that plant mechanics often rely on dynamic helical systems15, 16, 17, 18, 19 has motivated the development of a variety of chiral actuators where molecules were used either as active transducers of energy11, 13, 20, 21 or as relays for humidity or temperature changes 22, 23, 24, 25. These soft actuators have demonstrated reversible shape transformation, work, and motility,26 but the response speed and power produced remain moderate, mainly owing to the lack of mechanisms to drive non‐linear actuation 27.…”

Multiresponsive actuators based on modified electrospun films

“…As a key part, so actuators, which respond to applied external stimuli such as thermal, 7 light, [8][9][10][11] pressure, 12-14 chemical, 15,16 electric 17-20 and humidity [21][22][23][24][25] or magnetic elds, [26][27][28] have been explored for biomimetic applications. 10,16,22,24 Among various actuating structures, bilayer structures have been widely used to convert dimensional changes into bending motions. [1][2][3][4][5][6] A bilayer system typically consists of an active layer that contracts or expands in response to an external stimulus and a passive layer that remains intact.…”

“…[29][30][31] Active-layer materials are mainly based on materials such as gels, 8,15,16 paper, 20,32 silver nanowires (AgNWs), 22,33 carbon nanotubes (CNTs), [34][35][36][37] and graphene and its derivatives. [9][10][11][17][18][19]38,39 However, the manufacturing and preparation processes for some of the materials are complex, or their cost is relatively high. In addition, present actuators are mostly triggered by a single stimulus.…”

Nature‐Inspired Electrochemical Energy‐Storage Materials and Devices

“…[45][46][47][48] While the abundant examples of natural structures with known stableness, geometry configuration, surface wettability and mechanical property provide clues for rational design of nanostructured active materials with desired performance. [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] (4) What's more, nature-inspired routines are also useful for rational design of ideal binders Currently, tremendous efforts are being devoted to develop high-performance electrochemical energy-storage materials and devices. Conventional electrochemical energy-storage systems are confronted with great challenges to achieve high energy density, long cycle-life, excellent biocompatibility and environmental friendliness.…”