清华大学王超团队报道了动态热稳定超分子网络低熵罚离子偶极相互作用的多价设计。相关研究成果发表在2023年1月31日出版的《美国化学会杂志》。

动态超分子网络总是伴随着热不稳定性。根本原因是大多数可逆的非共价键在高温下迅速衰变，并在100°C以下解离。

该文中，研究人员实现了高温稳定性超过150°C的可逆离子-偶极相互作用。合成的超分子网络可以同时具有1.32MPa的机械强度（原始材料的14.8倍）、动态自愈能力和高达200°C的稳定工作温度。从即使在100°C下也能延长600 s的特征弛豫时间来看，该材料是热稳定最好的动态超分子聚合物之一。这些显著的性能是通过使用新的多价但低熵罚分子设计实现的。因此非共价键可以达到较高的焓，同时使熵主导的热离解最小化。

附：英文原文

Title: Multivalent Design of Low-Entropy-Penalty Ion–Dipole Interactions for Dynamic Yet Thermostable Supramolecular Networks

Author: Zhekai Jin, Tao Chen, Yuncong Liu, Wenwen Feng, Lili Chen, Chao Wang

Issue&Volume: January 31, 2023

Abstract: Dynamic supramolecular networks are constantly accompanied by thermal instability. The fundamental reason is most reversible noncovalent bonds quickly decay at elevated temperatures and dissociate below 100 °C. Here, in this paper, we realize a reversible ion–dipole interaction with high-temperature stability exceeding 150 °C. The resultant supramolecular network can simultaneously possess mechanical strength of 1.32 MPa (14.8 times that of pristine material), dynamic self-healing capability, and a stable working temperature of up to 200 °C. From the prolonged characteristic relaxation time of 600 s even at 100 °C, our material represents one of the most thermally stable dynamic supramolecular polymers. These remarkable performances are achieved by using a new multivalent yet low-entropy-penalty molecular design. In this way, the noncovalent bond can reach a high enthalpy while minimizing the entropy-dominated thermal dissociations.

DOI: 10.1021/jacs.2c12133

Source: https://pubs.acs.org/doi/10.1021/jacs.2c12133