Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh.
Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
J Mater Chem B. 2022 Oct 26;10(41):8386-8397. doi: 10.1039/d2tb00172a.
Tuning the self-assembled structures in amorphous hydrogels will enrich the functionality of hydrogels. In this study, we tuned the structure of a photonic hydrogel, which consists of polymeric lamellar bilayers entrapped inside a polyacrylamide network, simply by molecular triggering using an ionic surfactant. Owing to the binding of ionic surfactants (sodium dodecyl sulfate), the lamellar bilayers comprising non-ionic polymeric surfactants [poly(dodecyl glyceryl itaconate)] changed to micelles, whereas the unidirectional lamellar structure was preserved in the hydrogel. The bilayer-micelle structure transition caused a dramatic decrease in the swelling anisotropy and mechanical softening of the photonic gel. With the micelle structure, the softened gel shows fast (0.3 s) and reversible color change over the entire visible light range in response to a small mechanical pressure (5 kPa). This low stress-induced color-changing hydrogel could be applied as a visual tactile sensor in various fields, especially in biomedical engineering.
调整无定形水凝胶中的自组装结构将丰富水凝胶的功能。在这项研究中，我们通过使用离子型表面活性剂的分子触发，简单地调整了由聚合物层状双层夹在聚丙烯酰胺网络中的光子水凝胶的结构。由于离子型表面活性剂（十二烷基硫酸钠）的结合，由非离子型聚合物表面活性剂[聚（十二烷基甘油琥珀酸酯）]组成的层状双层转变为胶束，而水凝胶中保留了各向异性层状结构。双层-胶束结构的转变导致光子凝胶的溶胀各向异性和力学软化急剧下降。具有胶束结构的软化凝胶在响应小机械压力（5kPa）时，在整个可见光范围内表现出快速（0.3s）和可逆的颜色变化。这种低应力诱导变色水凝胶可应用于各个领域，特别是在生物医学工程中的视觉触觉传感器。
