Photoinitiating Systems Based on Anthraquinone Derivatives: Synthesis of Antifouling and Biocide Coatings

Abstract

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 monomers 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 through a hydrogen abstraction mechanism upon light illumination, followed by 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, for example, 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 stainless‐steel substrates. Interestingly, antibacterial tests of the GPTMS coatings showed efficient antifouling and biocide properties against E. coli and S. aureus.

Quinizarin Derivatives as Photoinitiators for Free-Radical and Cationic Photopolymerizations in the Visible Spectral Range

“…Similar results have been demonstrated by Xiao et al using four dihydoxyanthraquinone derivatives upon blue LED irradiation . More recently, a new efficient three-component photoinitiating system based on 2,6-diaminoanthraquinone was used to initiate upon visible-light exposure, the cationic polymerization of epoxy monomers concomitantly with the photoinduced sol–gel process of a reactive hybrid organic–inorganic precursor …”

“…13 More recently, a new efficient three-component photoinitiating system based on 2,6diaminoanthraquinone was used to initiate upon visible-light exposure, the cationic polymerization of epoxy monomers concomitantly with the photoinduced sol−gel process of a reactive hybrid organic−inorganic precursor. 14 The limited investigations concerning the use of anthraquinone (AQ) derivatives as visible-light-absorbing photoinitiators for the free-radical and cationic photopolymerizations prompted us to develop new AQ structures. The novelty of such AQ derivatives is to be used as (i) a visible photosensitizer and a photopolymerizable monomer since allyl and epoxy photopolymerizable moieties have been added to the AQ structures and (ii) an antibacterial agent since these new molecules can generate singlet oxygen.…”

Bio-sourced monomers and cationic photopolymerization–The green combination towards eco-friendly and non-toxic materials

“…It seems interesting to mention that some other studies investigated the use of anthraquinone derivatives as efficient photosensitizers to initiate cationic photopolymerization reactions upon exposure to visible light sources, however the amino-and hydroxy-substituted anthraquinones that are described in these works are not naturally occurring dyes [291][292][293].…”

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

“…However, light-induced activation of anthraquinone derivatives in combination with different additives [e.g., tertiary amines, iodonium salts, etc.] to generate active species capable of promoting cationic or free-radical photopolymerizations has been reported. ,, We have first investigated the overall photochemical reactivity of AQ-ZnPc possessing both phthalocyanine and anthraquinone moieties in the presence of Iod or MDEA by steady-state photolysis. Figure highlights that the absorbance of AQ-ZnPc slightly decreases during the LED@405 nm light irradiation under air indicating its low photochemical reactivity.…”

“…Similar results have been presented by Xiao et al using four dihydoxyanthraquinone derivatives for the FRP and CP upon irradiation with a blue LED bulb. 23 Versace et al have recently developed a performing three-component photoinitiating system 24 based on 2,6-diaminoanthraquinone (AQD), Iod, and benzyl alcohol derivatives to perform upon light exposure, the CP of hybrid organic−inorganic epoxy monomers altogether with their hydrolysis and condensation. Such investigation has led to the synthesis of new interesting antibacterial coatings against two bacteria strains.…”