Self-driven piezotronic effect enhances the photocatalytic bactericidal activity of polyvinylidene fluoride/bismuth...

The antimicrobial properties of dressings are critical for wound recovery, as they serve as the first line of defense against microbial invasion. In this study, bismuth sulfide (Bi₂S₃) was synthesized and immobilized onto a piezoelectric polyvinylidene fluoride (PVDF) fiber membrane to achieve enhanced photocatalytic sterilization efficacy. Scanning electron microscopy and transmission electron microscopy analyses unambiguously verified that Bi₂S₃ formed a nanosheet structure on the PVDF surface. The specific surface area of the PVDF/Bi₂S₃ composite was measured to be 175.3 m²·g^-1, indicating a high surface area for potential antimicrobial activity. The PVDF/Bi₂S₃ composite demonstrated strong light absorption in both the visible and near-infrared regions, generating significant amounts of reactive oxygen species under simulated sunlight. Photocatalytic sterilization experiments revealed that PVDF/Bi₂S₃ exhibited superior antibacterial performance against both Escherichia coli and Methicillin-Resistant Staphylococcus aureus compared to PVDF or Bi₂S₃ powder alone. These findings demonstrate that the inherent polarization field within the PVDF matrix significantly enhances the photocatalytic efficiency of Bi₂S₃. Furthermore, under vibration conditions, the piezotronic effect of the PVDF membrane further improved the photocatalytic sterilization efficiency of PVDF/Bi₂S₃ compared to static conditions. When applied as a dressing for trauma treatment in mice, the movement and limb traction of the animals activated the piezotronic effect of the PVDF fiber membrane. This dynamic interaction enhanced the photocatalytic bactericidal properties of the dressing, thus promoting wound healing and optimizing the overall efficacy of PVDF/Bi₂S₃ in wound treatment.