Xu Bo, Luo Zixiong, Xiao Rui, Wang Zhijian, Yang Jiping
Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China.
State Key Laboratory of Fluid Power and Mechatronic Systems, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, 310027, P. R. China.
Macromol Rapid Commun. 2022 Dec;43(23):e2200580. doi: 10.1002/marc.202200580. Epub 2022 Aug 12.
Mechanochromic hydrogels, which can switch their color in response to the applied external force, have shown great potential in stress visualization and damage indication. However, the kinds of colors in the reported mechanochromic hydrogels are limited. It is challenging to develop mechanochromic hydrogels with new kinds of color changes. Herein, a kind of mechanochromic double network (DN) hydrogel is reported based on the hybrid phenol-rhodamine mechanophore. The hydrogels turn into orange color with an emission wavelength of around 566/574 nm in response to tensile and compressive stress. The DN hydrogels show great reversibility. The color of DN hydrogels vanishes slowly after releasing the stress. The stress sensitivity can be tailored by the crosslinking density and the mechanophore concentration of the first network. In addition, the influence of the pH on the mechanochromic properties of DN hydrogels is also studied. This study provides an insightful study in tuning the stress sensitivity in the mechanochromic hydrogel, which will be beneficial for the development of mechanochromic materials.
机械变色水凝胶能够响应外部施加的力而改变颜色，在应力可视化和损伤指示方面展现出了巨大潜力。然而，已报道的机械变色水凝胶的颜色种类有限。开发具有新型颜色变化的机械变色水凝胶具有挑战性。在此，基于混合酚 - 罗丹明机械发色团报道了一种机械变色双网络（DN）水凝胶。该水凝胶在拉伸和压缩应力作用下会变成橙色，发射波长约为566/574纳米。DN水凝胶具有良好的可逆性。释放应力后，DN水凝胶的颜色会缓慢消失。应力敏感性可通过第一网络的交联密度和机械发色团浓度进行调整。此外，还研究了pH对DN水凝胶机械变色性能的影响。本研究为调节机械变色水凝胶的应力敏感性提供了有见地的研究，这将有利于机械变色材料的发展。
