Photoregulating of Stretchability and Toughness of a Self‐Healable Polymer Hydrogel

• Published in: Macromolecular rapid communications. Vol. 39; no. 10; pp. e1800018 - n/a
• Main Authors: Xiong, Chenxiao, Zhang, Lidong, Xie, Meiran, Sun, Ruyi
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2018
• Subjects: Construction materials; host–guest interactions; Hydrogels; Irradiation; Light irradiation; multifunctional hydrogels; photoregulated mechanical properties; Radiation; self‐healing; Strain; Stretchability; surface patterning; Tensile stress; Toughness; photoregulated mechanical properties; multifunctional hydrogels; self-healing; surface patterning; host-guest interactions
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201800018

Supramolecular hydrogels that are assembled through dynamic host–guest interactions have presented apparent potential in the construction of materials with promising performance. Herein, a photoregulated hydrogel cross‐linked by host–guest interactions with multifunctions of high stretchability, strong toughness, and rapid self‐healing property is reported. The hydrogel exhibits unique light‐responsive property due to the introduction of two photoisomerized groups. For example, the stress–strain curve of the original hydrogel indicates 1020% rupture strain with the maximum tensile strain value of 214 kPa. Upon 365 nm light irradiation for an hour, its tensile strain increases to 15 times with lower tensile stress indicating a better stretchability. Moreover, the hydrogel is photochromic and surface patternable, where it can reversibly switch color between luminous yellow and brown while exposed to 365 and 440 nm light irradiation. It holds great promise for applying in self‐recovering optically controlled and labeled elastic mechanical materials. A photoresponsive supramolecular hydrogel is constructed with spiropyran‐functionalized polyacrylamide main chain and host–guest interactions between azobenzene and β‐cyclodextrin pendant groups. The hydrogel not only combines fundamental mechanical properties including high strength and strong toughness with dynamic properties such as rapidly self‐recovery in one system, but also succeeds in adjusting its stretchability and toughness with light.