具有仿生增强的多重力响应智能聚合物的合成及性能研究

In this proposal, we will first incorporate novel covalent mechanophores of different characteristics into the center of a polymer chain. Through the use of sonochemistry, the information of mechanochemical activity among different mechanophores will be readily obtained. Then, biomimetic modular structures can be readily formed through the introduction of supramolecular mechanophore. Moreover, multiple types of covalent mechanophores will also be introduced into a single polymer chain to construct multiple mechanoresponsive materials. Synergistic effect as well as selective and sequential activation of the mechanophores will be achieved to provide multilevel stress reliefs and super self-toughening. In addition, hetro-Diels-Alder reaction between the activated mechanophore and the embedded reactants will be mechanically triggered, resulting in stress induced cross-inking and generation of new mechanophores in-situ. The newly formed mechanophore is expected to be mechanoresponsive as well and its mechanochromic property can be utilized to develop novel stress/damage sensor. By using the newly formed mechanophores together with the original covalent mechanophore as well as the supramolecular mechanophore, supramolecular and dynamic covalent self-healing will be achieved. Emphasis will be placed on the stress induced crosslinking, the generation of new covalent mechanophores in-situ, and the self-healing properties based on the newly formed mechanophores. We envisage that this pioneering work on multiple mechanoresponsive polymers will partially solve the challenges and create new topics in the study of mechanoresponsive smart polymers.

在本项目中，我们首先将不同性质的新共价键型力色团置于聚合物链中间，通过超声力化学快速获得不同共价键型力色团的相对强弱。然后，利用超分子力色团形成的仿生模块结构来增强材料的力学性能，并在同一体系中引入多种共价键力色团，构建同时具有超强力学性能和多重力响应性能的智能聚合物材料。通过多种力色团的协同作用和选择性/次序行活化，获得多级应力消除效应；利用应力引发的杂DA反应，实现力致共价交联进一步增强材料力学性能，同时原位生成新的力色团；利用新力色团的力响应特性，发展具有基于新型力致变色的应力感应和损害预报功能的新材料；同时利用超分子力力色团和新生成力色团实现超分子和动态共价多重自修复。重点研究不同力色团的比较方法和表征手段、应力引发的共价交联、新力色团的原位生成、新力色团的力响应特性和动态共价自修复功能。期望在仿生高分子和多重力响应聚合物的交叉研究中做出新的亮点。

本研究将多个力色团或力色团与超分子单元置于同一体系中，通过仿生设计合成了具有可控、次序性力响应功能的“多模式”复合力色团，并以此为基础制备了具有多种力响应功能且力学性能优异的高分子聚合物材料。（1）将螺吡喃与超分子单元融入同一体系并考察外力作用下的次序性活化顺序；（2）利用基于肉桂酸二聚体的大环力色团实现单次活化释放2.5 nm的储存长度，延缓聚合物断裂，同时活化后的产物具有光致自修复功能；（3）利用肉桂酸大环力色团成功制备门控力色团，实现肉桂酸力色团与环丁烯力色团的可控次序性活化；（4）开发螺噻喃力色团，实现旧力色团生成新力色团引发力致交联反应；（5）发展定量研究力致变色力色团的方法，并成功开发了螺噻喃、罗丹明、香豆素和肉桂酸等力致变色型力色团。