Synthesis, structure and properties of a new two-photon photopolymerization initiator

Abstract

A new two-photon free-radical photopolymerization initiator, (E,E)-4-{2-[p′-(N,N-di-n-butylamino)stilben-p-yl]vinyl}pyridine (abbreviated to DBASVP), has been synthesized. Quantum chemistry calculations showed that the new initiator possesses a large delocalized π electron system, a large change in dipole moment on transition to the excited state and a large transition moment. The calculated two-photon absorption cross-section is as high as 881.34 × 10⁻⁵⁰ cm⁴ s photon⁻¹. The single-photon and two-photon absorption and fluorescence properties in various solvents have been investigated carefully. The new initiator exhibits outstanding solvent-sensitivity, which experimentally interprets the excellent electron delocalized properties of the molecule. A microstructure has been fabricated under irradiation at 800 nm using a 200 fs, 76 MHz Ti:sapphire femtosecond laser.