Bio-Mimetic Actuators of a Photothermal-Responsive Vitrimer Liquid Crystal Elastomer with Robust, Self-Healing, Shape Memory, and Reconfigurable Properties

Abstract

Soft actuators with apparent uniqueness in exhibiting complex shape morphing are highly desirable for artificial intelligence applications. However, for the majority of soft actuators, in general, it is challenging to achieve versatility, durability, and configurability simultaneously. Enormous works are devoted to meet the multifunctional smart actuators, to little effect. Herein, self-healing and bio-mimetic smart actuators are proposed based on azobenzene chromophores and dynamic disulfide bonds. Benefiting from the dynamic and drivable vitrimer liquid crystal elastomer (V-LCE) materials, a series of actuators with single or compound dynamic three-dimensional structures were fabricated, which were capable of double-stimuli response and complex "bionic" motions, such as the blooming of a flower, grasping and loosening an object, and so forth. Moreover, these flexible actuators showed fascinating properties, such as high robustness, excellent elasticity−plasticity shape-memory properties (R f and R r are close to 100%), easily reconfigurable property, and self-healing. This smart V-LCE provides a guideline to design and fabricate soft versatility actuators, which has prospects for developing smart bionic and artificial intelligence devices.

Vitrimers: Using Dynamic Associative Bonds to Control Viscoelasticity, Assembly, and Functionality in Polymer Networks

“…In one recent example, ionic vitrimers have been used as reversible adhesives (Figure d), where UV light reversibly triggers the bond exchange in dynamic networks leading to greater adhesion strength . Vitrimers have also received recent attention as actuators, ,− in many cases combining liquid crystalline elastomers with dynamic bonds. These systems can actuate either by heat or light stimuli and often operate as shape memory systems.…”

Photoreversible Bond-Based Shape Memory Polyurethanes with Light-Induced Self-Healing, Recyclability, and 3D Fluorescence Encryption

“…). − Benefiting from this interesting property, SMPs with a designable structure and deformable shape memory effect have been widely used in biomedicine, aerospace, flexible electronics, etc., promoting the rapid development of smart materials. To date, most of the developed SMPs, especially those with high toughness, are cross-linked with irreversible covalent bonds and further cannot be recovered to their original mechanical properties by self-healing. , Once damaged (scratched, torn and punctured) during load operation, they need to be replaced immediately, resulting in a serious waste of material and environmental pollution. − To improve the durability, stability, and sustainable utilization of materials, more diverse functions, such as stretchability, high toughness, and excellent self-healing, should be integrated into the same network system. − However, based on the mutual exclusion between mechanical toughness and self-healing properties of all polymer materials, SMPs cannot simultaneously possess high toughness and good self-healing.…”

Styrene‐butadiene‐styrene‐based shape memory polymers: Evolution and the current state of art

“…Elastomers have proved to be excellent materials in the purview of shape memory behavior with high deformation, excellent shape fixity, and recovery along with a quick recovery rate 159,160 . SBS in this context has proved to be an excellent thermoplastic for metamorphosing into a shape memory polymer 161,162 .…”