Bioinspired gradient hydrogel actuators with rewritable patterns and programmable shape deformation

Abstract

The botanical world inspires scientists to develop various smart actuators with diverse mechanical motions in response to external stimuli. However, it is challenging to obtain programmable and reversible hydrogel actuators....

Bionic ordered structured hydrogels: structure types, design strategies, optimization mechanism of mechanical properties and applications

“…This is due to the uneven distribution of water caused by the gradient changes in their internal structure, resulting in swelling of the upper part, bending of the lower part, downward movement of the petiole and closing of the leaves. 15,98…”

“…As an illustration, gradient structure hydrogels inspired by Mimosa pudica leaflets could respond to temperature changes due to a gradient distribution in their centers that induced asymmetric contraction. 15 In addition to this, hybrid gradient hydrogels are produced by copolymerising two or more monomers in different proportions to produce a gradient. During homogeneous transition of its hybrid structure, a modification in performance can be achieved.…”

“…Currently, popular areas of research on bionic ordered structures involve lamellar structures patterned after shells, 14 fasciculate structures mirroring tendons, 10 gradient structures resembling Mimosa , 15 array structures similar to biofilms, 16 fiber chain structures that mimic spider silk 17 and so on. Due to their unique structural traits and biomechanical properties, researchers generally employ a variety of constituent materials, construction methods, and structures to prepare bionic ordered structured hydrogels for design purposes.…”

Cellulose Nanocrystal‐Based Gradient Hydrogel Actuators with Controllable Bending Properties

“…[23][24][25] By combining CNC with different materials, it is possible to expand the range of functions utilizing electrophoresis. [26][27][28] CNCs are widely used as reinforcement fillers in polymeric composite materials, enhancing the mechanical strength of the composite by improving its energy adsorption characteristics. Thus, it is postulated that a gradient distribution of CNCs could locally influence the deswelling behavior of stimuli-responsive hydrogels, resulting in stimulusinduced curvature.…”

“…Recently, Chang et al have reported high-performance gradient hydrogel actuators that utilize high-strength CNC derived from marine animals. [26,27] While, from the perspective of utilization of readily available renewable resources, it is preferable to use plant-derived CNCs. Hence, we prepared CNCs from different sources from plant-derived raw materials to reveal the dimensional effect of CNC on the performances.…”