Probing the Effect of Anion Structure on the Physical Properties of Cationic 1,2,3-Triazolium-Based Poly(ionic liquid)s

International audienceTo extensively explore the influence of anion structure on the physical properties of poly(ionic liquid) s (PILs) a series of PILs having main-chain 1,2,3-triazolium cations was synthesized via copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) followed by N-alkylation with iodomethane and anion metathesis with different metal salts, that is, Li(CF3SO2)(2)N, Li(CF3CF2SO2)(2)N, K(FSO2)(2)N, K(CF3SO2)N(CN), Ag(CN)(2)N, and sodium 4,5-dicyano-1,2,3-triazolate. To isolate the effect of anion on physical properties of PILs, a common iodide precursor was used to maintain constant the average degree of polymerization (DPn) and chain dispersity. Detailed structure/properties relationship analyses demonstrated a lack of correlation between anion chemical structure, ionic conductivity, and glass transition temperatures. Among synthesized series, the PIL derivative having bis(trifluoromethylsulfonyl) imide counter anion showed the best compromise in performance: low glass transition temperature (T-g=-268 degrees C), high thermal stability (T-onset = 340 degrees C) and superior ionic conductivity (sigma(DC) = 8.5 x 10(-6) S/cm at 30 degrees C), which makes it an interesting candidate for various key modern electrochemical applications

Multicolor photoinitiators for radical and cationic polymerization: mono vs. poly functional thiophene derivatives

International audienceThiophene and polythiophene derivatives have been prepared and used as photoinitiators upon visible light exposure. Their abilities to initiate, when combined with an iodonium salt (and optionally Nvinylcarbazole), a ring-opening cationic photopolymerization of epoxides and radical photopolymerization of acrylates under various different irradiation sources (i.e., very soft halogen lamp irradiation, laser diode at 405, 457, 473, 532, and 635 nm and blue LED bulb at 462 nm) have been investigated. These systems are characterized by a remarkable performance for purple to red light exposure. They are also particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and lead to the formation of an interpenetrated polymer network IPN (30 s for getting tack-free coatings). Their migration stability is excellent in the cured IPNs. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photolysis techniques

From Alpha to Omicron BA.2: New digital RT-PCR approach and challenges for SARS-CoV-2 VOC monitoring and normalization of variant dynamics in wastewater

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