液态金属/环糊精复合仿生记忆水凝胶

doi:10.11949/0438-1157.20250237

摘要/Abstract

摘要：

通过无溶剂搅拌策略将液态金属（LM）与β-环糊精（CD）复合制备液态金属/β-环糊精（LM/CD）复合物，并以此为引发剂引发丙烯酰胺（AAm）单体共聚，成功合成具有梯度LM/CD分布的水凝胶。CD的疏水空腔可包封LM液滴，其表面羟基通过配位作用与LM形成物理锚定，结合空间位阻效应抑制颗粒团聚，在搅拌转速2000 r/min、时间30 min条件下可有效分散60%（质量分数）的LM，LM/CD可形成具有自支撑性与导电性的片层结构。通过敲击诱导LM定向析出使LM/CD水凝胶底部电阻发生变化，电化学测试表明，LM/CD水凝胶底面电阻与敲击次数呈线性关系，可以实现仿生记忆功能且在压缩-释放循环中电阻保持稳定。与传统导电聚合物改性水凝胶相比，该材料兼具高导电性（底面电阻0.808 Ω）、优异力学性能及稳定的记忆行为，为智能仿生材料设计提供了新思路。

关键词: 凝胶, 仿生记忆, 液态金属, 环糊精, 导电性能, 团聚, 聚合物

Abstract:

The liquid metal (LM)/β-cyclodextrin (CD) composite was prepared by compounding liquid metal (LM) with β-cyclodextrin (CD) through a solvent-free stirring strategy. This composite was used as an initiator to trigger the copolymerization of acrylamide (AAm) monomers, successfully synthesizing hydrogels with gradient LM/CD distribution. The hydrophobic cavity of CD can encapsulate LM droplets, and its surface hydroxyl groups form physical anchors with LM through coordination interactions. Combined with the steric hindrance effect to inhibit particle agglomeration, this method can effectively disperse 60% (mass fraction) of LM under stirring conditions of 2000 r/min for 30 min, allowing LM/CD to form a self-supporting and conductive lamellar structure. The bottom resistance of LM/CD hydrogel was changed by tapping to induce directional precipitation of LM. Electrochemical tests showed that the bottom resistance of LM/CD hydrogel was linearly related to the number of tapping, which could realize bionic memory function and keep the resistance stable during compression-release cycle. Compared with traditional conductive polymer-modified hydrogels, this material combines high conductivity (bottom surface resistance 0.808 Ω), excellent mechanical properties, and stable memory behavior, providing new ideas for the design of intelligent biomimetic materials.

Key words: gels, biomimetic memory, liquid metal, cyclodextrin, conductivity, agglomeration, polymers

中图分类号:

O 69

林星月, 徐秀彬, 李鑫, 韦林洁, 王灏, 姚希, 吴旭. 液态金属/环糊精复合仿生记忆水凝胶[J]. 化工学报, 2025, 76(11): 6077-6085.

Xingyue LIN, Xiubin XU, Xin LI, Linjie WEI, Hao WANG, Xi YAO, Xu WU. Liquid metal/cyclodextrin composite biomimetic memory hydrogel[J]. CIESC Journal, 2025, 76(11): 6077-6085.

图/表 14

图1 LM/CD的制备示意图

Fig.1 Preparation diagram of LM/CD

图2 搅拌转速对LM分散的影响：不同转速时LM/CD复合物的图像

Fig.2 Effect of stirring speed on liquid metal dispersion: images of LM/CD composite at different rotation speeds

图3 不同搅拌转速下LM/CD 60复合物的TEM图像及对应的EDS元素映射图

Fig.3 TEM images and corresponding EDS element mapping diagrams of LM/CD 60 composites at different stirring speeds

图4 转速为2000 r/min时LM/CD 40 （a）、 LM/CD 50 （b）、LM/CD 60 （c）、LM/CD 70 （d）复合材料及其局部放大电子图像

Fig.4 LM/CD 40 (a), LM/CD 50 (b), LM/CD 60 (c), and LM/CD 70 (d) composites and their partially enlarged electron images at a rotation speed of 2000 r/min

图5 转速为2000 r/min时LM/CD 40 （a）、LM/CD 50 （b）、LM/CD 60 （c）、LM/CD 70 （d）复合材料的扫描电子显微镜（SEM）谱图以及对应的元素映射图（EDS）

Fig.5 SEM images of LM/CD 40 (a), LM/CD 50 (b), LM/CD 60 (c), LM/CD 70 (d) composites with 2000 r/min, as well as corresponding EDS images

图6 CD、LM/CD的FTIR谱图

Fig.6 FTIR spectra of CD and LM/CD

图7 自支撑薄膜导电原理示意图（圆形代表LM，梯形代表CD）

Fig.7 Schematic diagram of principle of self-supporting film conductivity (circle represents LM, and trapezoid represents CD)

图8 不同LM含量的LM/CD在不同压力下制备的片层导电性能

Fig.8 Electrical conductivity of layered materials compressed under different pressures, composed of LM/CD with varying liquid metal contents

图9 LM/CD 60在4 MPa压力下的自支撑能力（a）以及片层良好的导电性（b）

Fig.9 Illustrates self-supporting capability (a) and good lamellar conductivity (b) of LM/CD 60 under a pressure of 4 MPa

图10 不同LM含量的LM/CD水凝胶力学性能

Fig.10 Mechanical properties of LM/CD hydrogels with varying LM content

图11 电阻随敲击次数变化

Fig.11 Resistance variation with number of taps

图12 LM/CD水凝胶元素分布分析：（a）凝胶截面二次电子像，（b）镓元素映射图和（c）铟元素映射图；（d）凝胶上表面二次电子像，（e）对应的元素（氧、铟、镓、碳）映射图；（f）凝胶下表面（原始）二次电子像，（g）对应的元素（氧、铟、镓、碳）映射图；（h）凝胶下表面敲击300次后的二次电子像，（i）对应的元素（氧、铟、镓、碳）映射图

Fig.12 Elemental distribution analysis of LM/CD organogel: (a) cross-sectional secondary electron image of gel, and (b) gallium (Ga) and (c) indium (In) elemental mappings, respectively； (d) secondary electron image of upper gel surface, and (e) corresponding elemental mappings (O, In, Ga, C)； (f) secondary electron image of pristine lower gel surface, and (g) corresponding elemental mappings (O, In, Ga, C)； (h) secondary electron image of lower gel surface after 300 cycles of tapping, and (i) corresponding elemental mappings (O, In, Ga, C)

表1 水凝胶上表面和下表面的EDS元素含量

Table 1 Elemental composition of top surface and bottom surface of hydrogel by EDS

元素	含量/%（质量分数）
元素	上表面	下表面
C	60.83	41.98
O	35.16	20.12
Ga	3.44	28.58
In	0.57	9.32
总量	100.00	100.00

图13 水凝胶在拉伸和释放条件下电阻的恢复情况:拉伸-释放的电阻变化图(a) 3次循环拉伸后; (b) 6次循环拉伸后; (c) 10次循环拉伸后(a) after 3 stretching cycles; (b) after 6 stretching cycles; (c) after 10 stretching cycles

Fig.13 Resistance recovery of hydrogels under stretching and releasing conditions: a graph showing resistance changes during stretching and releasing

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