Ding Xiaoya, Li Gao, Zhang Peng, Xiao Chunsheng
Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China.
University of Science and Technology of China, Hefei 230026, China.
ACS Macro Lett. 2020 Jun 16;9(6):830-835. doi: 10.1021/acsmacrolett.0c00330. Epub 2020 May 21.
Thermally reversible dynamic covalent bonds (TRDCBs) have attracted great interest for building polymers with self-healing and adaptable properties in bulk. However, none of the developed TRDCBs can be used in aqueous media for the fabrication of thermally reversible dynamic hydrogels due to the requirement of high temperature to initiate the retro-reaction or the susceptibility to hydrolysis. Herein, we report a thermally reversible dynamic covalent C═C double bond that was formed by catalysis-free Knoevenagel condensation (CKC) between benzaldehyde and cyanoacetate end-functionalized polymers in aqueous solution. The as-formed TRDCB shows typical thermal reversibility in the aqueous media under mild temperatures (4-70 °C). Constructing hydrogels with this TRDCB led to the formation of thermally reversible dynamic hydrogels with intriguing self-healing, injectable, thermosensitive, and thermoplastic properties. Overall, this work not only broadens the application of TRDCBs in aqueous media but also provides a thermally reversible dynamic hydrogel for potential use in various biomedical fields.
热可逆动态共价键（TRDCBs）在构建具有本体自愈合和适应性特性的聚合物方面引起了极大的关注。然而，由于引发逆反应需要高温或易水解，已开发的TRDCBs均不能用于水性介质中制备热可逆动态水凝胶。在此，我们报道了一种热可逆动态共价C═C双键，它是通过苯甲醛与氰基乙酸酯端基功能化聚合物在水溶液中进行无催化Knoevenagel缩合（CKC）反应形成的。所形成的TRDCB在温和温度（4 - 70°C）的水性介质中表现出典型的热可逆性。用这种TRDCB构建水凝胶导致形成具有有趣的自愈合、可注射、热敏和热塑性特性的热可逆动态水凝胶。总体而言，这项工作不仅拓宽了TRDCBs在水性介质中的应用，还提供了一种热可逆动态水凝胶，有望用于各种生物医学领域。
