A mussel-inspired semi-interpenetrating structure hydrogel with superior stretchability, self-adhesive properties, and pH sensitivity for smart wearable electronics

Conductive hydrogel-based flexible sensors have garnered significant interest in the realm of smart wearable electronics. Nevertheless, the development of multifunctional hydrogels continues to be an essential challenge, given that conventional hydrogels typically exhibit singular functionality and frail mechanical properties. In this study, inspired by mussels, a multifunctional conductive hydrogel with superior stretchability, adhesion, pH sensitivity, and antibacterial activation was prepared with polydopamine (PDA)-coated carbon nanotubes (CNTs) doped. Particularly, a semi-interpenetrating network structure with multiple cross-linking sites was constructed, resulting in the hydrogel with a super-stretching ability (1904%) and fatigue resistance. The PDA-CNTs in the system not only imparted self-adhesive properties to the hydrogel but also facilitated efficient ion and electron transfer with the synergistic effect of Al 3+ , thereby enhancing the sensitivity (GF = 3.81) and cycling stability. The flexible sensor based on this hydrogel could be applicable to detect various human activities and also exhibited huge potential in the field of information sensing and transmission. Multifunctional conductive hydrogel-based flexible sensors have garnered significant interest in the realm of smart wearable electronics.