LAUSR

In both organic and polymer synthesis, photochemistry of Charge Transfer Complexes (CTCs) is considered as a powerful approach to expand visible-light-driven radical chemistry reaction. We report herein on the development of a class of useful CTCs using pyridinium salts as efficient electron acceptors (combined with N, N, 3, 5-tetramethylaniline, TMA) to achieve a multi-wavelength (375-560 nm) metal-free LED photopolymerization process under mild conditions (open to air, without monomer purification and inhibitor removal). The UV-vis absorption spectra and molecular modeling simultaneously verified its potential blue-green absorbing wavelength range. Also, their good thermal initiation behavior at relatively low temperature makes it easier to achieve thick samples and/or polymerization in the shadow region in practice. More importantly, with excellent photoinitiating capability, the formulation was successfully applied to direct laser write (DLW) and high-resolution 3D printing, yielding series of objects with well-defined structures, such as letters, ring, solid square and chess piece. These new pyridinium salt acceptors further extend the applicability to visible photopolymerizable resins and additive-containing formulations for efficient surface and deep curing. This article is protected by copyright. All rights reserved.