Mussel‐inspired chitosan‐based hydrogel sensor with pH‐responsive and adjustable adhesion, toughness and self‐healing capability

Abstract Conductive hydrogels with adhesion, toughness and self‐healing properties have attracted more and more attention due to their wide application in wearable devices and health monitoring. However, integrating adhesion, toughness and self‐healing properties into a hydrogel remains a serious challenge. Herein, we prepared an ionic conductive hydrogel using Fe 3+ ion, tert‐butyl acetoacetate‐modified polyvinyl alcohol (PVAA) and catechol‐modified chitosan (CCS) based on mussel inspired catechol chemistry. The adhesion, toughness and self‐healing properties of the hydrogel could be easily regulated. The prepared hydrogel had excellent adhesion properties (102 kPa), rapid self‐healing properties (5 min at room temperature), pH responsiveness and toughness up to 1386 kJ/m 3 . Therefore, the hydrogel could be used as a wearable sensor to detect human movement, and it could also be used as a bioelectrode to collect electrocardiographic signal (ECG). It might not only show great potential in applications such as wearable devices and health monitoring, but also promote the development of next‐generation adhesive hydrogel bioelectronic devices.