Niu Wenwen, Li Zequan, Liang Fengli, Zhang Houyu, Liu Xiaokong
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, P. R. China.
Angew Chem Int Ed Engl. 2024 Mar 4;63(10):e202318434. doi: 10.1002/anie.202318434. Epub 2024 Jan 30.
Supramolecular polymer networks (SPNs), crosslinked by noncovalent bonds, have emerged as reorganizable and recyclable polymeric materials with unique functionality. However, poor stability is an imperative challenge faced by SPNs, because SPNs are susceptible to heat, water, and/or solvents due to the dynamic and reversible nature of noncovalent bonds. Herein, the design of a noncovalent cooperative network (NCoN) to simultaneously stabilize and reinforce SPNs is reported, resulting in an ultrastable, superrobust, and recyclable SPN. The NCoN is constructed by multiplying the H-bonding sites and tuning the conformation/geometry of the H-bonding segment to optimize the multivalence cooperativity of H-bonds. The rationally designed H-bonding segment with high conformational compliance favors the formation of tightly packed H-bond arrays comprising higher-density and stronger H-bonds. Consequently, the H-bonded crosslinks in the NCoN display a covalent crosslinking effect but retain on-demand dynamics and reversibility. The resultant ultrastable SPN not only displays remarkable resistance to heat up to 120 °C, water soaking, and a broad spectrum of solvents, but also possesses a superhigh true stress at break (1.1 GPa) and an ultrahigh toughness (406 MJ m ). Despite the covalent-network-like stability, the SPN is recyclable through activating its reversibility in a high-polarity solvent heated to a threshold temperature.
由非共价键交联的超分子聚合物网络（SPN）已成为具有独特功能的可重组和可回收聚合物材料。然而，稳定性差是SPN面临的一项紧迫挑战，因为由于非共价键的动态和可逆性质，SPN易受热、水和/或溶剂的影响。在此，报道了一种用于同时稳定和增强SPN的非共价协同网络（NCoN）的设计，从而得到一种超稳定、超强韧且可回收的SPN。NCoN是通过增加氢键位点并调整氢键片段的构象/几何形状来构建的，以优化氢键的多价协同作用。合理设计的具有高构象顺应性的氢键片段有利于形成包含更高密度和更强氢键的紧密堆积的氢键阵列。因此，NCoN中的氢键交联显示出共价交联效应，但保留了按需的动力学和可逆性。所得的超稳定SPN不仅在高达120°C的温度下表现出对热、水浸泡和多种溶剂的显著抗性，而且在断裂时具有超高的真实应力（1.1 GPa）和超高的韧性（406 MJ m）。尽管具有类似共价网络的稳定性，但通过在加热到阈值温度的高极性溶剂中激活其可逆性，该SPN是可回收的。
