Study on a polymerizable visible light initiator for fabrication of biosafety materials

Developing low-mobility visible light photoinitiators (PIs) will open new application fields for photopolymerization. In this paper, a polymerizable visible light PI (PBDA) containing acryloyl groups based on a benzylidene cyclopentanone moiety was synthesized and characterized by H-1-NMR, C-13-NMR, UV-Vis spectrum and HR-MS. Its linear absorption appears in the visible region (400-530 nm) and overlaps very well with the emission spectrum of a common blue light source. Under the irradiation of a 473 nm diode laser, the polymerization of commercial acrylate monomers can be induced directly by PBDA. Due to the existence of acryloyl groups, PBDA can be linked into the polymer networks, which decreases its migration in the matrix and improves the biosafety of the end-products. Furthermore, PBDA presents a large two-photon absorption cross-section around 800 nm based on its D-p-A-p-D conjugated structure. 3D microstructures were fabricated using the formulation containing PBDA as PI by two-photon photopolymerization.