离子键强化的隔离结构导电胶乳及其复合材料的电阻-应变特性

The giant challenge of the pressure-sensitive conductive rubber is to develop a facile and low-cost approach to fabricate conductive rubber-based sensors with high sensitivity and excellent repeatability. However, limited progress has been made in this area. Aiming at this issue, this project is proposed to utilize the unique amphiphilicity and 1-D nanostructure of cellulose nanocrystals (CNC) to tune the morphology of conductive rubber latex at micro- and nanoscale. Consequently, a highly segregated conductive network with outstanding sensitivity to external stimuli would be constructed. In order to realize rapid recovery and reconstruction of conductive network, unique self-healable ionic bonds would be constructed between filler-based conductive network and polar rubber latex (e.g. bromobutyl rubber) through grafting of vinylimidazole onto the surface of CNC. Additionally, specific nanostructure design is applied to conductive rubber latex-based composites to achieve synchronous 'destroy-reconstruction' change of conductive network with the deformation of elastic base. As a result, various low-cost, highly sensitive, reproducible and highly flexible sensing materials are fabricated. They are expected to have the capability of detecting multiple external forces (e.g. stretching, pressure, torsion, etc.). This project aims to explore the effect of segregated conductive network on the resistance-strain relationship of the prepared composites and the role of ionic bonds-based supramolecular interaction in the repair and reconstruction of conductive network. Meanwhile, new approach and principle of constructing unique nanostructure in the conductive rubber latex-based composites through layer-by-layer technique would be established. Based on the aforementioned studies, this project would provide promising materials and technologies for the development of new generation wearable electronic devices.

针对现有力敏导电橡胶不能兼顾高灵敏度和重复性以及低成本、易加工等要求的难题，本项目拟利用纳米纤维素（CNC）独特的两亲性和纳米尺寸结构，对导电胶乳进行微纳尺度形态调控，构筑对外场作用响应灵敏的隔离结构导电网络；通过在CNC表面接枝乙烯基咪唑，在填料导电网络与溴化丁基橡胶等极性胶乳间构建具有自修复功能的离子键连接，实现导电网络的快速回复与重建；进而，在导电胶乳复合材料中引入特殊的结构设计，使得导电网络能够随着弹性基底的形变而破坏-重构，制备多种成本低、可大面积加工、柔韧性好、灵敏度高、重复性好，并且可感知多种外力作用（拉伸、压力、扭曲等）的柔性传感材料。研究隔离结构导电网络对复合材料传感特性的影响规律，阐明基于离子键的超分子相互作用对导电网络重建与修复的影响机制，建立基于层层组装方法在导电胶乳复合材料中引入特殊结构设计的新技术新原理，为可穿戴电子设备的开发提供关键材料和技术。

本项目按照任务书认真开展研究工作，针对现有力敏导电橡胶不能兼顾高灵敏度和重复性以及低成本、易加工等要求的难题，通过调控填料组装网络与界面超分子交联网络，制备高灵敏、重复性好、易加工、力学性能优良的柔性应变传感材料，为可穿戴电子设备的开发提供关键材料和技术，全面完成项目任务目标。取得的主要成果如下：利用纳米纤维素独特的两亲性和结构导向作用，对导电胶乳进行微纳尺度形态调控，构筑对外场作用响应灵敏的隔离结构导电网络，突破现有力敏传感材料高灵敏度与宽检测范围不能兼顾的难题，建立了基于层层组装加工方法在导电胶乳复合材料中引入特殊结构设计的新技术新原理；通过在填料组装网络与橡胶基体间构建多重氢键、离子键、配位键等界面可逆交联网络，实现力学性能与导电性能的实时、多次自修复，制备具有超高灵敏度、可监测微小生理活动的自修复应变传感器；针对现有柔性传感材料设计依赖于结构试制、缺乏有效指导等瓶颈问题，创建橡胶填料导电网络力场响应可视化仿真模型，揭示复杂微纳结构力场演变机制及结构-性能构效关系，指导设计制备了多种高性能橡胶力敏传感材料。在Angewandte Chemie International Edition, Advanced Functional Materials, Materials Horizons等本领域重要学术期刊发表SCI论文35篇，均标注本基金项目资助，4篇论文入选ESI高被引论文；申请中国发明专利2项；培养博士研究生2名，硕士研究生7名。本项目建立的乳液模板自组装制备隔离结构功能弹性体及弹性体界面超分子增强等新技术具有应用前景，正在开展产业化应用推广。

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