多重网络导电水凝胶的可控制备及其自修复拉伸应变传感器应用研究

Stretchable strain sensors have wide applications in human health monitoring, electronic skin, human-machine interaction, and soft robots. Recently, conductive hydrogel has emerged as a promising material for the fabrication of strain sensors due to the advantages of intrinsically high stretchability, soft nature, good safety, and conceivable self-healing capability. However, the poor mechanical strength highly hinders its application for wearable sensors. Even though it has reported that the strength and toughness of hydrogel materials could be obviously enhanced by constructing double-network structure, it is still challenging to develop conductive hydrogel with comprehensive properties including high tensile strain, high strength, high toughness, good elastic resilience, and fast self-healing ability, etc. In particular, it has a trade-off between the high toughness and the good elastic resilience and self-healing ability. Herein, we will synthesize such a stretchable and self-healable conductive hydrogel with excellent comprehensive properties through building multiple cross-linking networks including hydrogen bonds, ion coordination bonds, and interpenetrating structure, etc. Meanwhile, conducting polymer will be introduced into the hydrogel by in situ polymerization. The synergistic effect of multiple cross-linking networks will be optimized to simultaneously achieve high toughness, good elastic resilience, and fast self-healing ability. The experimental conditions will be investigated for controllable synthesis of conductive hydrogel, and the relationships between component, morphology, and property will be studied. In addition, wearable strain sensors will be assembled for human motion monitoring application.

拉伸应变传感器可广泛用于人体健康监测、电子皮肤、人机交互以及软体机器人等。导电水凝胶由于本征的高拉伸性、柔软性和安全性，以及可能的自修复能力，近两年成为开发拉伸应变传感器的新兴选择。然而，机械强度低是限制其应用的最大障碍。虽然通过构建双重网络结构可以显著提高水凝胶的强度和韧性，但是开发综合性能优异（包括高拉伸率、高强度、高韧性、高回弹性、快速自修复能力等）的导电水凝胶仍极具挑战，特别是高韧性与高回弹性和自修复能力之间存在一定的矛盾。本项目拟通过分子设计构建多重网络交联结构（包括氢键、离子配位键以及分子链缠绕等），并原位聚合引入导电高分子组分，制备具有高拉伸率、高弹性以及快速自愈能力的导电水凝胶。将优化多重网络交联的协同增强效应，特别是同时满足高韧性与高回弹性及自愈能力；实现导电水凝胶的可控制备，建立“组分-形貌-性能”的构效关系；并组装可拉伸应变传感器用于人体运动监测。

导电水凝胶具有良好的柔性、导电性和生物安全性，可广泛应用于柔性传感器、可穿戴生物电子和柔性能源器件等。然而，制备兼具高强度、高拉伸和高导电性的柔性导电水凝胶仍具挑战。本项目以开发高导电性柔性水凝胶为目标，通过分子设计和原位聚合，采用“一锅法”合成了具有多重网络结构的导电水凝胶，并开发了其在可拉伸应变传感器、电生理信号监测、及柔性能源器件中的应用。主要研究成果包括：1）发展了“一锅法”合成高拉伸、自修复导电水凝胶，将其应用于可拉伸应变传感器；2）通过“一锅法”合成了高离子导电和高粘附的水凝胶生物电极，用于电生理信号监测；3）开发了通过静电纺丝技术制备“即需型”导电性水凝胶，用于表皮生物电子；4）对离子导电水凝胶的导电机理和测试方法进行了分析和讨论；5）发展和建立了“电化学中和能”概念，并基于此，通过合成酸/碱不对称水凝胶电解质组装了一系列高电压柔性锌基电池。研究对制备水凝胶的条件进行了系统性优化，阐明了材料组分与性能之间的构效关系，为设计新型导电水凝胶提供了普适性的合成方法，并未开发新型柔性电子器件（传感器和能源器件）提供了新的研究思路和路径，对推动柔性电子的实际应用具有重要意义。在本项目的资助下，发表学术期刊研究论文11篇，发表学术专著章节1章，申请专利1项；协助培养2名博士毕业生，2名硕士毕业生，1名博士后；在国内外学术会议做邀请报告1人次，为中小学生开展科普讲座2次。