Polymer hydrogel drivers are a new class of smart materials that can produce reversible deformation or volume changes to external stimuli (light, heat, chemistry, electricity, etc.). As a kind of "soft and wet" material similar to biological tissue, hydrogel driver has great potential application value in the fields of software robot, artificial muscle and artificial valve.
To this end, Chen Tao and Zhang Jiayu, researchers of the Intelligent Polymer Materials team of the Institute of Materials Technology and Engineering of the Chinese Academy of Sciences, have carried out a series of work. The multi-functionality of the biomimetic hydrogel driver is realized by constructing an asymmetric anisotropic hydrogel and its composite system (Fig. 1). By selective local reduction of graphene oxide-poly N-isopropylacrylamide, researchers have obtained a "bionic grip" that can perform complex three-dimensional deformation under various external stimuli such as pH, temperature, near-infrared, and ionic strength. Adv. Funct. Mater. 2016, 26, 8670); based on long-term research in intelligent drive and intelligent color change, they developed a new intelligent biomimetic hydrogel with 3D complex drive-intelligent color-changing dual-function synergy (Adv Funct. Mater. 2018, 28, 1704568); In order to overcome the drawback that the hydrogel driver is difficult to drive away from the water environment, the construction of the water circulation system inside the double-layer hydrogel has successfully achieved water, oil, air, etc. Drive in a variety of environments (J. Mater. Chem. C 2018, 6, 1320); in addition, the combination of drive and shape memory is used as a source of force for shape memory materials to achieve controlled adjustment of material deformation ( Chem. Commun. 2018, 54, 1229).
Based on the above series of research results and recent research experience in biomimetic anisotropic hydrogel actuators, the researchers recently published a review article (Adv. Sci., 2018, 1801584), which systematically introduced bionic anisotropic water in recent years. Recent advances in gel drive related research. Among them, the construction methods of anisotropic structures, including two-layer structure, gradient structure, patterned structure and orientation structure, and their corresponding typical cases are carefully combed; the hydrogel driver is summarized and summarized. Applications that may exist in bionic devices such as actuators, walkers/swimmers, artificial valves, etc. In addition, through the introduction of fluorescence properties, shape memory functions, self-healing, etc., multi-functional hydrogel drivers have also become bionic anisotropic waters. An important research content of gel drivers. Finally, the researchers discussed the existing challenges of this type of material and its future direction, including how to accurately control the deformation, how to improve the hydrogel strength to achieve practical applications, how to improve the response speed. It is believed that in the near future, bionic anisotropic hydrogel drivers will achieve vigorous development.
The above work was supported by the National Natural Science Foundation of China (51773215, 21774138, 21644009), the Natural Science Foundation of Zhejiang Province (LY17B040003, LY17B040004), the Key Research Project of the Frontier Science of the Chinese Academy of Sciences (QYZDB-SSW-SLH036), and the support of the Chinese Academy of Sciences Youth Innovation Promotion Association ( 2017337).
Figure 1 Construction of a multifunctional biomimetic hydrogel driver
Figure 2 Anisotropic structure construction of biomimetic hydrogel driver and its potential application
Source: Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences
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