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

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.