Mussel-Inspired Adhesive\nand Carbon Fiber Conductive\nHydrogel for Flexible Sensors

Abstract

Conductive hydrogels, which are considered to be a promising\nmaterial\nfor human motion detection sensors, often display low flexibility,\nlimited elongation, and non-adhesive properties. Herein, a multifunctional\nhydrogel with self-adhesive, highly stretchable, and conductive properties\nwas developed by introducing polydopamine (DA) and carbon fiber (CF)\ninto polyacrylamide (PAAm) hydrogel. The DA was polymerized with oxygen\nto form polydopamine (PDA), and the PDA-CF-PAAm hydrogel was hybrid-crosslinked\nwith covalent bonds and recoverable non-covalent bonds including hydrogen\nbonds and π-π stacking. Therefore, the prepared PDA-CF-PAAm\nhydrogel exhibits high and reversible stretchability. Additionally,\nthe hydrogel demonstrates high adhesiveness on various substrate surfaces,\nsuch as paper, glass, rubber, and biological tissue surfaces due to\nthe catechol groups of PDA. Furthermore, the obtained PDA-CF-PAAm\nhydrogel is conductive because of the addition of CF. As a result,\nthe self-adhesive, highly stretchable, and conductive PDA-CF-PAAm\nhydrogel can be directly adhered to the skin as a strain sensor to\nmonitor human body motion. This work may expand the scope of multifunctional\nhydrogel preparation for flexible wearable devices.