Visible Light Anthraquinone Functional Phthalocyanine Photoinitiator for Free-Radical and Cationic Polymerizations

Abstract

We report for the first time the synthesis and use of a visible light-sensitive anthraquinone functional phthalocyanine (AQ-ZnPc) in combination with a suitable electron donor (methyldiethanol amine, MDEA), electron acceptor (iodonium salt), or H-donor (thiol derivative, trithiol) as photoinitiating systems for the free-radical and cationic photopolymerization. These unprecedented combinations for the FRP and CP under visible light irradiation promoted high acrylate and epoxy conversions with efficiency comparable to well-known camphorquinone-based photoinitiating systems. As evidenced by electron paramagnetic resonance and laser flash photolysis experiments, AQ-ZnPc acts either as an electron donor via a photoinduced electron transfer pathway with iodonium salt or as a proton/proton-coupled electron transfer promoter when combined with MDEA or a thiol derivative. Moreover, AQ-ZnPc was shown to be very active as a singlet oxygen promoter when introduced in an interpenetrated polymer network for preventing the adhesion and proliferation of bacteria under visible light activation.