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Query: UMLS:C0267964 (PAA)
 2,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stable dispersions of exfoliated graphene in aqueous media with the aid of the amphiphilic block copolymer poly(isoprene-b-acrylic acid) (PI-b-PAA), in the form of its anion, were used to electrostatically bind cationic 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphine tetra(p-toluenesulfonate) (H2P(4+)). A new graphene/PI-b-PAA(-)-H2P(4+) ensemble was formed and examined by dynamic light scattering, UV/Vis and fluorescence emission spectroscopy. The efficient fluorescence quenching of H2P(4+) in the graphene/PI-b-PAA(-)-H2P(4+) ensemble was probed by using steady-state and time-resolved photoluminescence, suggesting that electron/energy-transfer phenomena occur within the nanoensemble. Blank experiments validated the concept of electrostatic interactions that govern the formation of graphene/PI-b-PAA(-)-H2P(4+) ensemble, which signified the importance of graphene as an electron acceptor toward the preparation of some new donor-acceptor systems. Finally, kinetic analysis of the lifetime profiles of the fluorescence emission gave information regarding the quenching rate constant and quantum yield of the singlet excited state of H2P(4+) in the graphene/PI-b-PAA(-)-H2P(4+) ensemble.
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PMID:Photoinduced charge-transfer interactions on a graphene/block copolymer electrostatically bound to tetracationic porphyrin in aqueous media. 2372 31