Two D-π-A-type 2,2,2-trifluoroacetophenone derivatives, namely, 4′-(4-( N,N-diphenyl)amino-phenyl)-phenyl-2,2,2-trifluoroacetophenone (PI-Ben) and 4′-(4-(7-(N,N-diphenylamino)-9,9-dimethyl-9H-fluoren-2-yl)-phenyl-2,2,2-trifluoroacetophenone (PI-Flu), are developed as high-performance photoinitiators combined with an amine or an iodonium salt for both the free-radical polymerization of acrylates and the cationic polymerization of epoxides and vinyl ether upon exposure to near-UV and visible light-emitting diodes (LEDs; e.g., 365, 385, 405, and 450 nm). The photochemical mechanisms are investigated by UV-Vis spectra, molecular-orbital calculations, fluorescence, cyclic voltammetry, photolysis, and electron-spin-resonance spin-trapping techniques. Compared with 2,2,2-trifluoroacetophenone, both photoinitiators exhibit larger redshift of the absorption spectra and higher molar-extinction coefficients. PI-Ben and PI-Flu themselves can produce free radicals to initiate the polymerization of acrylate without any added hydrogen donor. These novel D-π-A type trifluoroacetophenone-based photoinitiating systems exhibit good efficiencies (acrylate conversion = 48%–66%; epoxide conversion = 85%–95%; LEDs at 365–450 nm exposure) even in low-concentration initiators (0.5%, w/w) and very low curing light intensities (1–2 mW cm⁻²). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1945–1954

An efficient strategy for comprehensive utilization of the conjugated sulfonium salt photoacid generator (PAG), namely, 3-{4-[4-(4-N,N′-diphenylamino)-styryl]phenyl}phenyl dimethyl sulfonium hexafluoroantimonate, was developed through photoinitiated cationic photopolymerization (CP) of epoxides and vinyl ether upon exposure to near-UV and visible light-emitting diodes (LEDs; e.g., 365, 385, 405, and 425 nm). Photochemical mechanisms were investigated by UV–vis spectra, molecular orbital calculations, fluorescence, cyclic voltammetry, and electron spin resonance spin-trapping analyses. Compared with commercial PAGs, the prepared conjugated sulfonium salt generated H⁺, which can be used as photoinitiator. Moreover, the fluorescent byproducts from photodecomposition can be used as photosensitizer of commercial iodonium salt in the photoinitiating systems of CP. These novel D-π-A type sulfonium-based photoinitiating systems are efficient (epoxide conversion = 85–90% and vinyl conversion >90%; LEDs upon exposure to 365–425 nm) even in low-concentration initiators (1%, w/w) and low curing light intensities (10–40 mW cm⁻²). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2722–2730

A new single-/two-photon sensitive monomer, (E)-5-(4-ethoxystyryl)−2-nitrobenzyl methacrylate (ENbMA), was synthesized and copolymerized with methyl methacrylate (MMA) to form a series of photosensitive copolymers P(ENbMA–MMA)s that were well characterized by ¹H NMR and GPC. The photochemical and photophysical properties of both photosensitive monomer and copolymers upon visible light irradiation were studied by UV–Vis, FTIR, and HPLC spectra, which confirmed that 5-(4-ethoxystyryl)-2-nitrobenzyl ester can be photolyzed effectively with generation of the corresponding 5-(4-ethoxystyryl)-2-nitrosobenzaldehyde and carboxylic acid groups. The successful photocleavage endowed the optimized copolymers with excellent micropatterning property due to the effective generation of alkaline-soluble carboxylic acid groups. Moreover, the high two-photon absorption cross-sections (over 20 GM at 800 nm) and the comparable photolysis upon two-photon NIR light irradiation of the chromophores provided the copolymers with significant application in two-photon microfabrication. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4099–4106, 2013