Photoinitiating Systems based on Anthraquinone Derivative: a Key Role in the Synthesis of Antifouling and Biocide Coatings upon Light Exposure

Performing photoinitiating systems combining 2, 6-Diaminoanthraquinone (AQD), iodonium salt (Iod) and benzyl alcohol derivatives have been developed to efficiently initiate the cationic polymerization of epoxy monomer upon light exposure. Electron Spin Resonance spin-trapping (ESR ST) experiments, fluorescence investigations and steady state photolysis have demonstrated that a dye-sensitized reaction occurs between AQD and the benzyl alcohol derivatives via a H-abstraction mechanism upon light illumination, followed by a reduction of Iod. The in situ liberation of protic acids promotes the cationic photopolymerization of epoxy monomers concomitantly with hydrolysis and condensation of the reactive methoxysilanes of an organic-inorganic precursor e.g. 3-Glycidyloxypropyltrimethoxysilane (GPTMS). Nanoindentation experiments and scratch resistance tests proved that the resulting GPTMS coatings exhibit very good resistance to brittle fracture and excellent adherence to the stainless steel substrates. Interestingly, the antibacterial tests on the GPTMS coatings have highlithed efficient antifouling and biocide properties against E. coli and S. aureus.