A Hydrophilic/Hydrophobic Janus Inverse-Opal Actuator via Gradient Infiltration

Abstract

Janus/gradient actuating materials have become promising candidates for actuating devices. The fabrication of functional Janus gradient actuators remains a challenge. This paper presents a facile fabrication of a hydrophilic/hydrophobic Janus inverse opal actuator via gradient infiltration. The Janus characteristics of the fabricated actuator were attributed to gradient infiltration along the thickness of the film caused by the gradient light intensity and the distinct polymerization behavior of ionic liquids and methyl methacrylate in the methanol system. The Janus film demonstrated directional bending upon water vapor adsorption, with a bending angle approaching 1440° in 4 s, accompanied by structure color/optic signal alteration. The actuating behaviors were effectively modulated by changing the composition of the film and the solvent system. Promising applications of this Janus solvent actuator were demonstrated in two sets of tests: driving an engine and lifting cargo. This work provides insight into the design and fabrication of multifunctional humidity-actuating materials.

Asymmetric elastoplasticity of stacked graphene assembly actualizes programmable untethered soft robotics

“…Recently, a variety of flexible morphing systems have been developed with configurable soft materials by taking the advantage of various mechanisms such as asymmetric thermal expansion 5,6 , liquid crystalline transitions 7,8 , phase transitions [9][10][11][12] , and anisotropic swelling [13][14][15][16][17][18][19][20][21] , etc. To achieve shape programming and customization, numerous efforts have been made by applying specific chemical structures through a variety of polymeric materials including shape memory polymers (SMPs) [22][23][24][25] , vitrimer 26 , hydrogel [27][28][29] , organogel 30 .…”

Intelligent Polymer‐Based Bioinspired Actuators: From Monofunction to Multifunction

“…[47] In addition to be triggered by gradient external stimuli, the bending of the bioinspired actuators can also be accomplished by introducing anisotropies through the thickness, which can be achieved by either a monolayer or bilayer/ multilayer structures. For the bioinspired actuators with monolayer structures, the anisotropies through the thickness can be achieved by building gradients/variations in crosslinking density, wettability, or orientations of mesogenic units through tuning different gradients in ionic diffusion, [48] water infiltration, [49] and photoalignment, [50] respectively. As for the bioinspired actuators with bilayer/multilayer structures, the anisotropies through the thickness are usually realized based on the differential coefficients of thermal expansion or different swelling/ shrinking ratios among different layers upon exposure to external stimuli.…”

Inorganic Photonic Microspheres with Localized Concentric Ordering for Deep Pattern Encoding and Triple Sensory Microsensor

“…Among them, photonic microspheres exhibit high flexibility, small size, and orientation‐independent structural color because of their spherical symmetry in geometry, making them appealing for a wide range applications, including advanced photonic devices, wide viewing‐angle displays, [ 5–9 ] biological sensors, [ 6,10–12 ] aesthetic pigments. [ 13–19 ] In particular, these photonic microspheres provide building blocks for constructing promising encoded patterns for complex bioassays and anti‐counterfeiting, [ 18,20–24 ] and to create standalone devices for environment stimuli sensing. [ 23,25–27 ]…”