Département de chimie, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada.
Key Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, 710072, China.
Angew Chem Int Ed Engl. 2023 Jun 5;62(23):e202302900. doi: 10.1002/anie.202302900. Epub 2023 Apr 28.
Poly(acrylic acid-co-N-vinylcaprolactam) (PAN) hydrogels containing multiple hydrogen bonds can exhibit pH-induced reversible dynamic responsive behaviors. When placing a transparent hydrogel in an acid bath, as hydrogen bonds between comonomer units involving protonated COOH groups are formed faster than water diffusion, a nonequilibrium light-scattering state is formed to turn the hydrogel opaque, while as the swelling equilibrium is reached over time, the hydrogel regains its transparency. Likewise, when the transparent, hydrogen-bonded hydrogel is subsequently immersed in DI water, faster water absorption occurs in where more COOH groups are deprotonated, which also generates a light-scattering state leading to opacity, while the transparency is slowly recovered after equilibrium. Using such two-way dynamic transparency evolution, a PAN-based hydrogel material is prepared to demonstrate a dynamic memory system for information memorizing-forgetting and recalling-forgetting.
含多重氢键的聚（丙烯酸-co-N-乙烯基己内酰胺）（PAN）水凝胶可以表现出 pH 值诱导的可逆动态响应行为。将透明水凝胶置于酸性浴中时，由于涉及质子化 COOH 基团的共聚单体单元之间的氢键形成速度快于水的扩散速度，因此会形成非平衡光散射状态，使水凝胶不透明，而随着时间的推移达到溶胀平衡，水凝胶会恢复其透明度。同样，当透明的氢键水凝胶随后浸入 DI 水中时，在更多 COOH 基团去质子化的地方会更快地吸收水，这也会产生光散射状态导致不透明，而在达到平衡后透明度会缓慢恢复。通过这种双向动态透明性演变，制备了一种基于 PAN 的水凝胶材料，以展示用于信息存储-遗忘和检索-遗忘的动态存储系统。
