Poly(meta/para-Terphenylene-Methyl Piperidinium)-Based Anion Exchange Membranes: The Effect of Backbone Structure in AEMFC Application.

A series of poly(meta/para-terphenylene-methyl piperidinium)-based anion exchange membranes devoid of benzylic sites or aryl ether bonds, that are vulnerable to degradation by hydroxide ions, are synthesized and investigated for their application as novel anion exchange membranes. The copolymers are composed of both linear para-terphenyl units and kink-structured meta-terphenyl units. The meta-connectivity in terphenyl units permits the polymer backbones to fold back, maximizing the interactions among the hydrocarbon polymer chains and enhancing the peripheral formation of ion aggregates, due to the free volume generated by the kink structure. The effects of the copolymer composition between para-terphenyl and meta-terphenyl on the morphology and the electrochemical and physicochemical properties of the corresponding polymer membranes are investigated.

Cooperative and FRET-Assisted Brightness Enhancement in Oligo(phenylene ethynylene): Quantum Dot Organic-Inorganic Nanohybrids.

Herein, we combine the ideas of concerted emission from fluorophore ensembles and its further amplification through FRET in an organic-inorganic hybrid approach. Spherical and highly fluorescent organic nanoparticles (FONPs, Φf =0.38), prepared by the self-assembly of oligo(phenylene ethynylene) (OPE) molecules, were selected as a potential donor material. This organic core was then decorated with a shell of fluorescent CdSe/ZnS core-shell quantum dots (QDs; ≅5.5 nm, Φf =0.27) with the aid of a bifunctional ligand, mercaptopropionic acid. Its high extinction coefficient (ϵ≈4.1×105 m-1 cm-1 ) and good spectral match with the emission of the FONPs (J(λ)≈4.08×1016 m-1 cm-1 nm4 ) made them a better acceptor candidate to constitute an efficient FRET pair (ΦFRET =0.8). As a result, the QD fluorescence intensity was enhanced by more than twofold. The fundamental calculations carried out indicated an improvement in all the FRET parameters as the number of QDs around the FONPs was increased. This, together with the localization of multiple QDs in a nanometric dimension (volume≈1.8×106  nm3 ), gave highly bright reddish luminescent hybrid particles as visualized under a fluorescence microscope.