Force induced fluorescence response of functional two-photon micro-nanofabrication photosensitive materials based on dynamic C-N Bonds

Epoxy acrylate (EA) has excellent thermal performance, mechanical properties, and chemical stability, making it become typical representative of thermosetting resins. Dynamic C-N bond was introduced through chemical click between triazolinedione (TAD) and indole, resulting in EA polymers with different mass ratios. Among them, the 80wt% EA-10:3 has strongest tensile strength of 71.03 MPa with an elongation at break of 7%, while the 90wt% EA-10:2.5 has relatively excellent modulus and hardness of 5.21 GPa and 223 MPa, respectively. In addition, 90wt% EA-10:3 polymer exhibits good two-photon polymerization printing performance with scanning speeds of 100 μm/s -100000 μm/s and laser powers of 5 mW-50 mW. Simultaneously the sample block exhibits mechanical properties with modulus and hardness of 5.12 GPa and 230 MPa under the laser powers of 30 mW. In situ relaxation fluorescence spectroscopy was used to characterize the dynamic behavior of C-N bonds in force reversible polymer networks. This work proposes a valuable strategy to enhance the functionality of EA polymers in various special performance material applications, while maintaining its strength and toughness.