Xie Fengjin, Gao Xinpei, Yu Yang, Lu Fei, Zheng Liqiang
Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, China.
Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources, Hainan University, No 58, Renmin Avenue, Haikou 570228, China.
Soft Matter. 2021 Dec 15;17(48):10918-10925. doi: 10.1039/d1sm01453f.
Gel electrolytes have aroused extensive interest for diverse flexible electronics due to their high ionic conductivity and inherent stretchability. However, gel electrolytes still face challenges in terms of mechanical properties, fatigue resistance, and environmental adaptation, which severely limit the practical application of gel-based electronics. In this paper, we have synthesized a novel polymerizable ionic liquid [SBMA][AA] by mixing zwitterionic sulfobetaine methacrylate with acrylic acid. Then a dually cross-linked single network poly(ionic liquid)/ionic liquid (DCSN PIL/IL) ionogel was prepared by a simple one-step photopolymerization of the [SBMA][AA] in another IL 1-ethyl-3-methylimidazolium dicyanoamide ([EmIm][DCA]). The synergistic effect between covalent crosslinking and dynamic physical crosslinking points endows the ionogel with good mechanical properties as well as outstanding fatigue resistance. Gratifyingly, the entrapment of [EmIm][DCA] in the ionogel matrix yields excellent environmental adaptability and high ionic conductivity. Meanwhile, the DCSN PIL/IL ionogel also exhibited strong adhesive capacity due to the abundance of carboxyl and sulphonic acid groups. The outstanding electromechanical properties make the DCSN PIL/IL ionogel a perfect candidate for strain sensors to monitor diverse human body activities, such as the movement of the thumb knuckle and handwriting. Interestingly, the DCSN PIL/IL ionogel also displayed high responsiveness to humidity. Therefore, it is believed that this DCSN PIL/IL ionogel offers a broad prospect in flexible strain-humidity bimodal sensors.
凝胶电解质因其高离子电导率和固有的拉伸性，在各种柔性电子器件中引起了广泛关注。然而，凝胶电解质在机械性能、抗疲劳性和环境适应性方面仍面临挑战，这严重限制了基于凝胶的电子产品的实际应用。在本文中，我们通过将两性离子甲基丙烯酸磺基甜菜碱与丙烯酸混合，合成了一种新型的可聚合离子液体[SBMA][AA]。然后，通过在另一种离子液体1-乙基-3-甲基咪唑二氰胺（[EmIm][DCA]）中对[SBMA][AA]进行简单的一步光聚合，制备了一种双交联单网络聚（离子液体）/离子液体（DCSN PIL/IL）离子凝胶。共价交联和动态物理交联点之间的协同作用赋予了离子凝胶良好的机械性能以及出色的抗疲劳性。令人欣慰的是，[EmIm][DCA]被困在离子凝胶基质中产生了优异的环境适应性和高离子电导率。同时，由于含有丰富的羧基和磺酸基团，DCSN PIL/IL离子凝胶还表现出很强的粘附能力。出色的机电性能使DCSN PIL/IL离子凝胶成为监测各种人体活动（如拇指关节运动和书写）的应变传感器的理想候选材料。有趣的是，DCSN PIL/IL离子凝胶对湿度也表现出高响应性。因此，人们认为这种DCSN PIL/IL离子凝胶在柔性应变-湿度双模态传感器方面具有广阔的前景。
