Phloroglucinol-Based Antimicrobial Shape-Memory Photopolymers for Microimprint Lithography

In this study, for the first time, biobased photopolymers were synthesized from phloroglucinol tris epoxy with and without different comonomers, phloroglucinol, 1,4:3,6-dianhydro-D-sorbitol, and 1,4-cyclohexanedimethanol. The rheological, thermal, mechanical, shape-memory, and antimicrobial properties of photopolymers were investigated. The addition of comonomers reduced the photocuring rate (gel time increased from 325 s to 434-861 s) and rigidity (storage modulus decreased from 330.76 to 15.42-85.77 MPa), reduced their brittleness, and increased the flexibility (elongation at break increased from 0.9 to 1.89-4.51%), although the tensile strength of the polymers remained sufficiently high (tensile strength was reduced from 292.00 to 132.62-234.54 MPa). All polymers exhibited a thermoresponsive shape-memory behavior as they could maintain a temporary shape below their glass-transition temperature and return to the permanent shape when the temperature was raised again above the glass-transition temperature. All polymers showed high antibacterial activity against Staphylococcus aureus (90.3-96.4%) and Escherichia coli (97.8-99.6%) even after 1 h of contact with bacteria. The photoresins were tested in microimprint lithography and confirmed to accurately reproduce the shape features of the 3D printed target. Compositions prepared with 1,4-cyclohexanedimethanol were the most promising due to fast photocuring and the highest flexibility. Synthesized biobased photopolymers have a wide range of properties, making them potential candidates for the production of functional coatings, biomedical devices, or flexible electronics.