Hydrogels
with multifunctional properties have attracted considerable
interest owing to their wide range of applications in soft robotics,
wearable device development, and tissue engineering. In this study,
an adhesive, self-healing, and antibacterial conductive poly(dopamine
methacrylate-co-methacrylatoethyl trimethyl ammonium
chloride-co-acrylic acid) (PDDA) hydrogel was prepared
by the free-radical copolymerization of dopamine methacrylate (DMA),
methacrylatoethyl trimethyl ammonium chloride (DMC), and acrylic acid
(AA). The adhesion property of the PDDA hydrogel was explored by regulating
the feeding ratios of AA, DMA, and DMC. The hydrogel with a DMA/DMC/AA
molar ratio of 1:4:40 exhibited strong adhesion to various materials
such as iron, wood, rubber, glass, polytetrafluoroethylene, and plastic.
Meanwhile, the hydrogel showed good antibacterial properties, which
had a good inhibitory effect against Escherichia coli (37%) and Staphylococcus aureus (44%).
In addition, because of its non-covalent bond interactions in the
cross-linking network, the hydrogel exhibited excellent self-healing
property when damaged. Moreover, the excellent ductility, biocompatibility,
and adhesion property of the hydrogel allow better adhesion to the
skin surface and conductivity to monitor the physiological activities
of the human body by means of the electrical signals recorded using
the transformation of strain responses. The self-healing, adhesive,
antibacterial, biocompatible, and conductive hydrogel has a wide range
of applications in electronic skin and wearable devices.