Synthesis and Structure-activity Relationship of Coumarin-based Oxime-esters as Two-photon Photoinitiators

doi:10.7517/issn.1674-0475.190603

Abstract

Abstract: Development of efficient two-photon initiators (2PIs) are critical to promote two-photon 3D printing speeds. On the basis of photodecarboxylation, two unimolecular 2PIs that contain coumarin moieties (as two-photon absorption chromophores) and oxime-ester groups (as initiation functional groups) were synthesized. The investigation of the photophysical and photochemical behaviors of the oxime-esters were conducted via quantum-chemical calculations and experimental tests. The results indicated that the 2PIs exhibits a broad absorption band ranging from 400 to 500 nm. Under visible LED light irradiation, the investigated oxime-esters decomposed and formed active free radicals to effectively induce polymerization of acrylates. Interestingly, the photoinitiators exhibit a good photobleaching property. In two-photon polymerization tests with acrylate formulations, the oxime-ester derivatives can be used to build complex 3D microstructures with high spatial resolution. The possible photopolymerization mechanism was proposed according to the quantum chemical calculation results.

Key words: photoinitiators, two-photon polymerization, photodecarboxylation, oxime-esters, coumarin

LI Mengqi, QIU Wanwan, HU Peng, ZHU Junzhe, LIU Ren, LI Zhiquan. Synthesis and Structure-activity Relationship of Coumarin-based Oxime-esters as Two-photon Photoinitiators[J]. Imaging Science and Photochemistry, 2019, 37(5): 415-427.

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