title: Comparison of the characteristic behavior of two azo dyes on temperature dependent microstructure changes in micelles and vesicles.
abstract: The new hydrophobic azo dye 4-(N-phenyl-N-decylamino)-4'-nitroazobenzene (AzoC10) has been synthesized. It is compared with 4-(N-phenylamino)-4'-nitroazobenzene (Azo) in terms of reactivity (k(iso) of the thermal cis-->trans isomerization, microsecond flash photolysis) and of the solvatochromic behavior (lambda(max) of the trans-isomer, UV/vis absorption), respectively, within membrane mimeting amphiphile microstructures in aqueous solutions of poly(ethylene oxide)(m)-poly(propylene oxide)(n)-poly(ethylene oxide)(m) micelles and of extruded vesicles. The temperature-induced micelle formation and phase transitions in bilayers of vesicles, respectively, caused characteristic discontinuous changes of k(iso) and lambda(max) with temperature. They differ between the two dyes due to their different solubilization sites and different impact on their microenvironment.
authors.affiliation: Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Fakultät für Chemie und Mineralogie, Universität Leipzig, Linnéstr. 2, D-04103 Leipzig, Germany.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Wen
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knoll
authors.forename: Helmut
authors.initials: H
authors.lastname: Knoll