Replacing the “inert” chemical bonds in traditional materials with dynamic bonds brings opportunities in designing renewable materials that repair, reprocess and recycle. Despite the many efforts made in covalent adaptable networks by elaborating a single type of dynamic covalent chemistry, the fabrication of double dynamic covalent polymeric networks, especially using simple small-molecule building blocks, still remains challenging. Here we report the solvent-free construction of a thermosetting material by combining 1,2-dithiolane-based reversible polymerization and dynamic covalent boroxine chemistry as crosslinkers. The resulting materials exhibit tunable mechanical properties, mechanical reprocessability, shape memory ability and closed-loop chemical recyclability. Quantitative kinetic analysis reveals the temperature-dependent apparent activation energy for the bond exchange of the resulting network as a result of the simultaneous integration of the two dynamic covalent bonds. Meanwhile, the boroxine units also act as a luminescent center to enable an emissive “organic glass” that can be used as a dual encryption material taking advantage of the reprogrammable shape-memory behavior of the dynamic network. Benefitting from the simple design, tunable variables and multi-functions, we envision that this double dynamic chemistry offers a robust scaffold and great chemical spaces for the design of dynamic polymeric materials.
Jingru Wang,Jiaxin Yang,Yanyan Li,Yang Li,Rui Xu,Feng Song
The widespread application of optical encryption materials with difficult imitation, multicolor-tunable emission and simple operation presents a promising strategy for secure communication and authentication of information. Herein, Eu-MOF grafted with coumarin 7 is successfully constructed through self-assembly process and a prismatic three-dimensional hyperbranched structure is formed. At room temperature, it can be excited to by ultraviolet light significantly different green and red light emission. With the temperature rising to 363 K, under the excitation of 360 nm, a continuous and programmable color transformation occurs, resulting in a fitted line with a fitting degree of 0.99745. In order to maintain robust reliability, regular alterations in accordance with temperature variations are assessed through temperature sensitivity, and the absolute sensitivity and relative sensitivity can reach up to 6.168 % K −1 and 4.387 % K −1 . Based on the abundant emission modes, we develop an asymmetric information security authentication program to simulate encrypted information communication, which provides reliable guidance on visualized information storage and encryption.
危险品化学品经营许可证（带存储）