标题：Self-Assembled Switching Gels with Multiresponsivity and Chirality
作者：Zhao, Wenrong;Wang, Dong;Lu, Hongsheng;Wang, Yangyang;Sun, Xuan;Dong, Shuli;Hao, Jingcheng
作者机构：[Zhao, W] Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan, 250100, China;[ Wang, D] Key Laborator 更多
通讯作者地址：[Sun, X]Shandong Univ, Key Lab Colloid & Interface Chem, Jinan 250100, Peoples R China.
来源：Langmuir: The ACS Journal of Surfaces and Colloids
摘要：A multiresponsive hydrogel material consisting of a commercial cationic surfactant and an azobenzene derivative functionalized with four carboxylic acid groups was constructed. The achiral azobenzene molecule as a gelator produces chirality at the supramolecular level in the presence of H+. The acid-induced gelation and morphology change of supramolecular gels were investigated in detail by cryogenic transmission electron microscopy (cryo-TEM), rheological measurements, circular dichroism (CD), and H-1 NMR spectra. Based on the results, a mechanism of the intermolecular H-bond-directed gelation and supramolecular chirality was proposed. Other than the pH sensitivity, the microstructure and the chirality of the hydrogel demonstrate reversible switching behavior in response to photoirradiation, on account of the photoisomerization of the azobenzene derivative. Accordingly, a chiroptical switch comprising four different states in response to pH and light stimuli is strategically constructed. Not only does the present system provide a good opportunity for investigating the gelation-induced supramolecular chirality by symmetry breaking totally based on achiral molecules, but it also proposes a new strategy to build multiresponsive supramolecular switches as particularly attractive for the future development of functional materials.