A Click Chemistry Strategy for the Synthesis of Efficient Photoinitiators for Two-Photon Polymerization

It is reported that efficient photoinitiators, suitable for two-photon polymerization, can be obtained using the copper catalyzed azide/alkyne cycloaddition reaction. This click chemistry strategy provides a modular approach to the assembly of photoinitiators that enables the rapid variation of key fragments to produce photoinitiators with desirable properties. To assess the performance of the first-in-class photoinitiators generated by this approach, a screening method is developed to enable the rapid determination of polymerization and damage thresholds in numerous photoresists during two-photon polymerization. The degree of consumption of vinyl groups (DC) and homogeneity of the polymerization are further assessed by micro-Raman spectroscopy. Finally, more complex structures are fabricated to demonstrate that the efficient two-photon polymerization of stable 3D microarchitectures can be achieved using triazole-based photoinitiators.