Relevance of linked dye‐coinitiator in visible three‐component photoinitiating systems: Application to red light photopolymerization

A new visible light photoinitiating system (PIS) containing a linked dye‐coinitiator dyad and a nondissociative electron donor was evaluated and compared with unlinked three components systems. Our results show that in the physical mixture of the three component PIS, addition of the nondissociative donor decreased the Rp to a great extent, whereas in combination with the dyads an increase in Rp is observed. The results were explained based on faster intramolecular electron transfer in linked pairs and point out the importance of linked initiator in three‐component PIS for the first time. This system is the first example of three‐components system with a nondissociative donor that would be useful for long life coating formulation. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4325–4330     

Monitoring ultrathin film photopolymerization of tetra‐alkylepoxyporphyrin by UV‐Vis spectroscopy

Cationic photopolymerization is a convenient in situ polymerization method for organic thin film preparation. In this work, the polymerization mechanisms is applied for highly viscous cross‐linking monomers, using tetra‐alkylepoxyporphyrin (TAEP) as a case study. By comparing the UV‐Vis spectra of the polymerized sample before and after the unreacted monomers have been dissolved, it is possible to estimate the polymerization yield. An IR spectrum of a reference thick film confirms full polymerization. Scanning fluorescence lifetime microscopy and AFM show the uniformity of the polymer. It was shown that photopolymerization is highly dependent on the substrate nature and requires at best case a 10 min illumination at 90 °C. Thermal polymerization of the same sample requires 10 min heating at 150 °C in dark. It was also shown that TAEP works as a self‐sensitizer for cationic photopolymerization. The proposed method is a mild and versatile technique for in situ preparation of thin polymeric films directly from chromophore monomers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6095–6103, 2009