A tough and piezoelectric poly(acrylamide/<i>N</i>,<i>N</i>-dimethylacrylamide) hydrogel-based flexible wearable sensor.

Wu, Mingyue; Wang, Guohui; Zhang, Mihan; Li, Jinchao; Wang, Chenglong; Sun, Guangdong; Zheng, Jinhuan · Soft Matter · 2024

basic_science · Level V

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Abstract

A flexible, tough, highly transparent and piezoelectric polyacrylamide hydrogel was fabricated induced by blue light photocuring, with camphorquinone/diphenyliodonium hexafluorophosphate (CQ/DPI) as the blue light initiator, acrylamide (AM) and <i>N</i>,<i>N</i>-dimethylacrylamide (DMAA) as monomers, polyethylene glycol diacrylate (PEGDA) as the crosslinker, lecithin as the dispersant, and BaTiO<sub>3</sub> as the piezoelectric material. Various performance tests were carried out on the hydrogel, and the results showed that lecithin enhances the dispersion of BaTiO<sub>3</sub> within the system and improves the tensile properties (>100% strain) of the hydrogel, and the addition of PEGDA not only improves the photopolymerization performance of the hydrogel, but also significantly improves its fracture strength (∼0.3 MPa). In addition, BaTiO<sub>3</sub> enables the resultant hydrogels to show excellent conductivity (>1.5) and stable response to strain. The assembled hydrogel sensor shows a sensitive response to human joint activities, which is expected to be applied in self-powered sensors and energy collection.