基于协同界面的石墨烯基自修复可穿戴应变传感器的构建及其应用研究

Wearable strain sensors have found potential applications in healthcare, patient self-assessment, health monitor, and therapeutics, and so on. However, conventional wearable strain sensors exhibit relatively poor electrical and mechanical properties upon mechanical deformations. In this project, a self-healable wearable strain sensor with enhanced electrical property, stretchable strength and adhesiveness is developed for human-motion detection, based on the synergistic effect from interfacial interactions and building blocks. The strain sensor is using graphene conductive hydrogel as the conductive sensing channel. Pyrene-terminated polymers are synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization via a pyrene-functional RAFT agent. The graphene-polymer composites are prepared by attaching polymers onto the basal plane of graphene nanosheets via π-π stacking interactions to obtain stable aqueous dispersions, with the ultimate aim of enhancing the conductivity of the strain sensor. In addition, reversible dynamic covalent bonds are introduced to induce synergistic interfacial interactions with π-π stacking interactions, and endow the hydrogel with self-healable, stretchable and adhesiveness properties. Based on these foreseeable advances, the self-healable wearable strain sensor in this project, could not only provide a novel approach for studying the effect of synergistic interfacial interactions on the formation of graphene-based self-healable wearable strain sensor, but also lead to the significant development of novel graphene-based self-healable wearable strain sensors.

可穿戴应变传感器在医疗健康等领域有广泛的应用潜力。然而，现有的可穿戴应变传感器在反复变形状态下，其优异的电学和力学性能易受到破坏。本项目旨在基于界面相互作用和基元材料的协同策略，构建一种高电导率、高拉伸性及皮肤粘附性的自修复可穿戴应变传感器，探讨其在人体运动信号检测方面的可行性。该应变传感器以石墨烯基导电水凝胶为导体，通过分子设计，在单体的活性聚合中引入芘结构，通过芘结构与石墨烯的π-π耦合作用，实现石墨烯纳米片的有序分散，进而提高应变传感器的导电性能。同时，在水凝胶中引入可逆动态共价键，构建基于石墨烯的强弱界面相互作用（动态共价键－π-π耦合作用）的协同界面，以赋予水凝胶自修复、高拉伸性及皮肤粘附性等性能。本项目的实施，不仅为解决强弱界面相互作用在石墨烯基自修复可穿戴应变传感器中如何协同作用这一关键科学问题提供思路，而且为研制出新型石墨烯基可穿戴应变传感器奠定理论和技术基础。

.导电水凝胶具有类似生物组织的电子学和力学特性，能把外部形变精确地转换成可记录的电信号，因此在柔性传感器领域有巨大的应用潜力。本项目合成了一系列不同组成、不同分子量的共聚物，制备了一系列石墨烯基导电水凝胶、MXene基导电水凝胶、离子导电水凝胶，利用导电水凝胶构建了一系列可穿戴应变传感器。明确了聚合物组成、结构、分子量等对水凝胶性能的影响，重点探讨了分子间相互作用（动态共价键、π-π 耦合作用、氢键、静电作用等）在导电水凝胶体系的构建及水凝胶性能调控中的作用及其协同效应，考察了导电水凝胶的导电性能、拉伸性能、粘附性能、自修复性能，以及应变传感器在不同环境下的传感性能。结果显示，通过调控水凝胶的分子间相互作用可以实现导电水凝胶的高拉伸性（拉伸应变最高1810%）、高电导率（电导率最高18.16 S/cm）、传感灵敏性（在微压区域的最大灵敏度可达39.34）、抗溶胀性(水中浸泡30天的平衡溶胀率为9%)。本项目研究为导电水凝胶应用于柔性应变传感器领域，如个性化医疗监护、人机交互和软机器人等领域提供了理论依据和技术支持。