Bioinspired Multi‐Stimuli Responsive Actuators with Synergistic Color‐ and Morphing‐Change Abilities

Abstract

The combination of complex perception, defense, and camouflage mechanisms is a pivotal instinctive ability that equips organisms with survival advantages. The simulations of such fascinating multi‐stimuli responsiveness, including thigmotropism, bioluminescence, color‐changing ability, and so on, are of great significance for scientists to develop novel biomimetic smart materials. However, most biomimetic color‐changing or luminescence materials can only realize a single stimulus‐response, hence the design and fabrication of multi‐stimuli responsive materials with synergistic color‐changing are still on the way. Here, a bioinspired multi‐stimuli responsive actuator with color‐ and morphing‐change abilities is developed by taking advantage of the assembled cellulose nanocrystals‐based cholesteric liquid crystal structure and its water/temperature response behaviors. The actuator exhibits superfast, reversible bi‐directional humidity and near‐infrared (NIR) light actuating ability (humidity: 9 s; NIR light: 16 s), accompanying with synergistic iridescent appearance which provides a visual cue for the movement of actuators. This work paves the way for biomimetic multi‐stimuli responsive materials and will have a wide range of applications such as optical anti‐counterfeiting devices, information storage materials, and smart soft robots.

Cellulose‐Based Soft Actuators

“…Alternatively, actuators with bilayer structure have been successfully developed to perform controllable deformations such as bending and bucking based on asymmetrical responsive properties of two different swelling layers. [62,67,80,81] Several approaches including coating, [66] selective implanting, [82] lithography techniques, [83] self-assembly [84] have also been explored to construct bilayer or multilayer hydrogel actuators. For instance, Shin and coworkers reported an bilayer actuator by using a moisture-adsorbing responsive membrane as an active layer, and combined with another inactive layer.…”

Recent Advances in Electronic Skins with Multiple-Stimuli-Responsive and Self-Healing Abilities

“…Once the self-healable materials occur mechanical breaking, polymer chains with low glass transition temperature and high mobility would quickly diffuse into the damaged areas and reconstruct the dissociated dynamic bonding linkage, which efficiently facilitate restore their original properties. Owing to their structural simplicity and healing repeatability, intrinsically self-healing systems are frequently adopted to fabricate self-recovering electronic sensors, supercapacitors, electrodes, semiconductor, cells and actuators [ 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 ]. In this section, we will discuss recent advances in the design strategy of self-healing materials and their potential applications in wearable e-skin devices.…”

A Perspective on Cephalopods Mimicry and Bioinspired Technologies toward Proprioceptive Autonomous Soft Robots

“…[283] Moreover, also by providing light to liquid crystal elastomers is possible to change their surface morphology [284] while changing the apparent coloration as well. [285,286] In conclusion, the "material" and "mechanical intelligence" is exploited in a vast range of demonstrators. However, to obtain a complete camouflaging behavior (both in its mechanical and optical features), especially in a robotic platform, a scaling-up is required, which must also encompass the integration of a "learning intelligence".…”