Constructing High-Efficiency Polyoxometalate-Based Antibacterial Hydrogels for Wearable Sensors

Conductive flexible hydrogel are widely used in wearable electronics owing to its desired conductivity, flexibility, adhesion, and mechanical properties similar to human tissue. Nevertheless, conductivity and bacterial infections are always critical issues for the long-term use of hydrogel wearable sensors. Herein, a multifunctional polyoxometalate-based hydrogel with both antibacterial and sensing performances are prepared by integrating polydopamine-functionalized polyoxometalates (POMs) particles into polyacrylamide matrix. To obtain rapid gelation times (to seconds), a dual autocatalytic system focused on lignin and copper ions was formed by activating ammonium persulfate to generate free radicals and initiating the free-radical polymerization of acrylamide monomers. The fabricated POM-based hydrogel exhibited high mechanical strength (135.8 kPa), conductivity (2.52 mS/cm), and antibacterial activity against Gram-positive/negative bacterial strains <i>Escherichia coli</i> (<i>E. coli</i>, 99.39%) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>, 99.42%); thus, they were utilized as wearable sensors. These sensors also exhibited high stability and repeatability during 6000 s stretching/releasing cycles; therefore, it were used to monitor the human motions of finger, wrist, and elbow. Together, this strategy not only provides approaches for designing POM-based hydrogel materials but also expands the potential application of POMs in the advanced wearable strain sensors and antibacterial field.