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Anthracene-, benzophenone-, and anthraquinone-based UV photoinitiators have been, respectively, covalently grafted on the [Mo6O19]2–polyoxometalate (POM) platform, affording highly colored charge transfer organo-imido Lindqvist complexes. It has been evidenced that photosystems combining N-methyldiethanolamine (MDEA) as the electron donor and these hybrid POMs promote free-radical photopolymerization of acrylate monomer derivatives under irradiation in the visible range, while in similar conditions, no polymerization was observed considering as photoinitiators a mixture of the organic and POM precursors. After 800 s, acrylate conversion yields up to 90% under 405 nm LED irradiation and 50% under 470 nm LED irradiation were thus obtained considering the POM-imidoanthraquinone (POM-AQ) compound. This shows that such organo-imido Lindqvist species can represent new easy-to-synthesize, efficient visible-light photoinitiators. Moreover, due to the presence of the POM, coatings prepared using the POM-AQ/MDEA/soybean oil epoxidized acrylate photosystem exhibit excellent mechanical properties, with very good flexibility, resistance to brittle fracture, and adherence to the steel. Finally, POM-AQwas shown to have a remarkable capacity to generate singlet oxygen species under visible light irradiation, and the antibacterial activity against Staphylococcus aureusunder solar light of the related POM-derived surface has been demonstrated.

Biosourced eugenol-based polymer networks have a potential functionality for antibacterial coating applications. The presence of carvacrol, a phenol compound, improves these properties. However, the relationship between the network structure and the macroscopic thermomechanical behavior is not known for these biopolymers. Thus, this work details a robust study of this relationship through a multiscale experimental approach combining Dielectric Spectroscopy, Dynamic Mechanical Analysis, tensile testing, and Time Domain Double-Quantum proton Nuclear Magnetic Resonance (DQ 1H NMR). It was shown that carvacrol has an influence on the molecular mobility of the materials. Namely, it induces the appearance of a shouldering on the γ relaxation and a diminishing of the main molecular α relaxation, Tα. More surprisingly, up to 20% wt, carvacrol increases the elastic E′ and Young’s Emoduli. This observation can be interpreted as an increase of the crosslink density of the networks. Time Domain DQ 1H NMR shows that the residual dipolar coupling constant also increases. Thus, carvacrol seems to act as both a thermal plasticizer and mechanical reinforcement, which may seem to be antagonistic trends. For carvacrol contents over 20% wt, these properties diminish because of a saturation of this molecule in the networks and the onset of a phase separation. By combining the aforementioned techniques, it was proven that carvacrol linearly increased the measured crosslink density and thermomechanical properties by physically bonding to the networks through π–π interactions. These interactions would act as physical crosslinks. This work demonstrates that by correlating the results of various multiscale experimental techniques, a better comprehension of the structure–property relationship can be established for biobased functional polymer networks.

We report the use of efficient visible-light sensitive allyl (QA) and epoxidized (QE) quinizarin derivatives as photoinitiating systems when combined with an appropriate electron donor (methyldiethanol amine, MDEA), an electron acceptor (iodonium salt, Iod), or a H donor (thiol derivative), for free-radical photopolymerization (FRP), cationic photopolymerization (CP), and a thiol–ene process. These systems have demonstrated excellent initiating properties under air or in laminated conditions under visible-light irradiation (LEDs@405, 455, and 470 nm or Xe lamp) for FRP, CP, or the thiol–ene process and appear more efficient than the well-known camphorquinone-based photoinitiating systems. As highlighted by electron paramagnetic resonance (EPR) and laser flash photolysis experiments, QA(or QE) acts either as an electron donor via a photoinduced electron transfer pathway with Iod or as a proton/proton-coupled electron transfer promoter with MDEA or a thiol derivative. Two types of interpenetrated polymer networks have been synthesized either by CP and the thiol–ene process with di(ethylene glycol) divinyl ether/trithiol or by a concomitant free-radical and cationic photopolymerization with an epoxide/acrylate blend mixture upon LED@455 or 470 nm exposure. Interestingly, the resulting quinizarin-derived materials showed antiadherence properties under visible-light exposure even after two cycles of antibacterial experiments. Quinizarin derivatives can not only initiate photopolymerization but also generate singlet oxygen on the surface of the materials for preventing the adhesion and proliferation of bacteria under visible-light activation.

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-ZnPcacts 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-ZnPcwas 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.

A quinoline-derived titanium complex (TiQ) is shown here to possess remarkable photosensitizing properties when treated with an iodonium salt (Iod) to initiate, under visible light irradiation, (i) the free-radical photopolymerization of acrylate monomer in aerated/laminate conditions, (ii) the cationic photopolymerization of epoxy monomer under air, and (iii) the in situ formation of Ti-based nanoparticles (NPs) inside coatings. The photochemical properties of the TiQ/Iod photoinitiating system have been probed by electron paramagnetic resonance, laser flash photolysis, and real-time Fourier transform infrared spectroscopy, which provide an insight into the possible radical/cationic pathways. The microstructural properties of the photosynthesized Ti-based NPs have been investigated by bright-field conventional transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy. The macroscopic mechanical properties of the resulting nanocomposite reveal that the generation of these Ti-based NPs in a polyacrylate/polyether blend matrix leads to an increase of mechanical resistance by toughening the matrix.

The characterization and the photochemical investigation of a RuIIcomplex (Ru(PPh3)3Cl2) having phosphine ligands are reported. DFT calculations and ESR spin trapping experiments revealed for the first time that the photodecomposition of the complex is governed by a homolytic cleavage of the P–(C6H5) bond generating phenyl radicals Ph•which are able to initiate the free radical polymerization of acrylate monomers. The addition of a H-donor HD plays a key role in the cationic photopolymerization of epoxides: (i) the reaction efficiency is enhanced using [Ru(PPh3)3Cl2]/HD and (ii) the in situformation of Ag nanoparticles is observed in the presence of Ru(PPh3)3Cl2/HD/AgSbF6according to the following reactions: Ph•/DH hydrogen abstraction yielding a D•radical and oxidation of D•by the silver salt.