Vanillin acrylate-based thermo-responsive shape memory antimicrobial photopolymers

Vanillin acrylate-based thermo-responsive shape memory photopolymers with high thermal stability, tunable mechanical properties, and antimicrobial activity have been developed. Photocurable resins containing one of the three commercial vanillin derivatives, vanillin diacrylate, vanillin dimethacrylate, and vanillin hydroxypropane dimethacrylate, and 1,3-benzenedithiol were tested. The results of dual curing systems with different ratios of thiol and acrylate (1:1 and 0.5:1) were compared. The reduction of thiol content increased the rate of photocuring, improved the mechanical performance of polymers (Young's modulus was increased from 1.4-3.5 to 3952.3-11339.4 MPa), and their heat resistance (the 10% weight loss increased from 277-327 to 294-341 degrees C). All polymers were able to return to their primary shape after deformation and maintain their temporary shape at a temperature lower than their glass transition temperature (-3-46 degrees C). Furthermore, all polymer films exhibited significant antibacterial activity against Escherichia coli and Staphylococcus aureus (cell reduction reached 99.8-100% after 24 h) and antifungal activity against Aspergillus flavus and Aspergillus niger (cell reduction reached 72.3-100% after 24 h).