Hexaarylbiimidazoles as visible light thiol-ene photoinitiators.

Objectives: The aim of this study is to determine if hexaarylbiimidazoles (HABIs) are efficient, visible light-active photoinitiators for thiol-ene systems. We hypothesize that, owing to the reactivity of lophyl radicals with thiols and the necessarily high concentration of thiol in thiol-ene formulations, HABIs will effectively initiate thiol-ene polymerization upon visible light irradiation.

Methods: UV-vis absorption spectra of photoinitiator solutions were obtained using UV-vis spectroscopy, while EPR spectroscopy was used to confirm radical species generation upon HABI photolysis.