Abstract:

The gel-based wireless strain sensor can transmit the human joint activity and language to mobile devices through wireless signal technology. It can real-time monitor the human movement or body rehabilitation, expanding the applications of gel sensors. Thus, the smart gel sensors have attracted increasing attention in recent years. However, the water molecules in the gels tend to crystallize at low temperatures, decreasing the flexibility and conductivity of the gels, which significantly restricts the use in cold environment. In addition, most gels are easily damaged due to the soft matrix and low strength, which will shorten its service life. Therefore, it is significant to develop the multifunctional gels with self-healing and low temperature resistance for prolonging the life and broadening applications of gel sensors. In this work, polyvinyl alcohol (PVA), butyl acrylate (BA), and phytic acid (PA) were used as raw materials, BA was polymerized by heat induced free radical polymerization in the mixture of PVA and PA using dimethyl sulfoxide (DMSO)/water (H₂O) as binary solvent. The wireless strain sensor based on poly(butyl acrylate) gels having low-temperature resistance, high stretching, and self-healing multi-functions were fabricated through the self-assembly of the multiple hydrogen bonds. The gel sensors could convert the mechanical movements (such as human joints) into the electrical signals after being connected into the wireless signal transmission modules, realizing the strain sensing. The performance of the gels was optimized by adjusting the BA content. When the BA content was 35%, the tensile strength and elongation at break of the wireless strain sensor reached 461kPa and 886%, respectively. The self-healing efficiency was 80% and the strain sensitivity was high (GF=0.77) at -25℃.

Key words: poly(butyl acrylate), low temperature resistant gels, self-healing, wireless strain sensing, self-assembly

摘要：

凝胶基无线应变传感器可以通过无线信号传输技术将人体关节活动和语言等信号传输到移动设备，实时监测人体的运动或康复。然而凝胶中的水分子在低温下会形成冰晶，导致凝胶失去柔韧性和导电性，限制了传感器在寒冷环境中的应用。本文以聚乙烯醇（PVA）、丙烯酸丁酯（BA）及植酸（PA）为原料，在二甲基亚砜（DMSO）/水（H₂O）的混合溶剂中通过热引发自由基聚合后，借助多重氢键自组装的作用制备了具有耐低温和自愈合功能特性的聚丙烯酸丁酯凝胶。将其串联至无线信号传输模块可将人体关节等机械运动转化成电信号从而实现无线应变传感功能。当BA质量分数为35%时，无线应变传感器的拉伸强度和断裂伸长率分别可达461kPa和886%，愈合效率为80%，-25℃下仍具有较高的应变灵敏度（GF=0.77）。

关键词: 聚丙烯酸丁酯, 耐低温凝胶, 自愈合, 无线应变传感, 自组装