国科温州研究院赵冬团队报道了基于牺牲构象方法的共价网络的能量耗散和增韧。相关研究成果于2024年10月15日发表于国际顶尖学术期刊《德国应用化学》。

共价聚合物网络因其理想的刚度和弹性而在各种工程应用中具有广泛的用途。然而，交联点之间的刚性共价化学结构对限制了其韧性的提高。尽管牺牲化学键的结合在通过能量耗散提高韧性方面显示出了希望，但复合材料网络难以保持快速恢复和刚度。因此，实现结合高强度、刚度、韧性和快速恢复性能的共价网络仍然是一个重大挑战。

为了应对这一挑战，研究人员提出了一种称为“牺牲构象”的新型牺牲结构。在该方法中，β-环糊精作为牺牲构象元件共价嵌入网络骨架中。与传统的共价网络（LCN）相比，设计良好的环糊精包埋共价网络（CCN）的杨氏模量提高了100倍，韧性提高了60倍。重要的是，CCN保持优异的弹性，确保变形后迅速恢复。这种牺牲构象策略能够有效地耗散能量，而不需要破坏化学键，从而克服了传统方法的局限性。

这一研究进展为设计和制造，具有优异机械性能和动态行为的先进弹性体和水凝胶，带来了巨大的希望。

附：英文原文

Title: Energy Dissipation and Toughening of Covalent Networks via a Sacrificial Conformation Approach

Author: Dong Zhao, Hao Wang, Zhiyou Wei, Zhiwei Liu, Bin Zheng, Zhaoming Zhang, Xuzhou Yan, Linli He, Tao Li

Issue&Volume: 2024-10-15

Abstract: Covalent polymer networks find wide utility in diverse engineering applications owing to their desirable stiffness and resilience. However, the rigid covalent chemical structure between crosslinking points imposes limitations on enhancing their toughness. Although the incorporation of sacrificial chemical bonds has shown promise in improving toughness through energy dissipation, composite networks struggle to maintain both rapid recovery and stiffness. Consequently, a significant challenge persists in achieving a covalent network that combines high strength, stiffness, toughness, and fast recovery performance. To address this challenge, we propose a novel sacrificial structure termed "sacrificial conformation." In this approach, β-cyclodextrin is covalently embedded into the network skeleton as the sacrificial conformation element.  Compared to traditional covalent networks (LCN), well-designed cyclodextrin-embedded covalent network (CCN) exhibit a 100-fold increase in Young's modulus and a 60-fold increase in toughness. Importantly, CCN maintains excellent elasticity, ensuring swift recovery after deformation. This sacrificial conformational strategy enables efficient energy dissipation without necessitating the rupture of chemical bonds, thereby overcoming the limitations of traditional approaches. This advancement holds great promise for the design and fabrication of advanced elastomers and hydrogels with superior mechanical properties and dynamic behavior.

DOI: 10.1002/anie.202416790

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202416790