title: Micelle structure in a photoresponsive surfactant with and without solubilized ethylbenzene from small-angle neutron scattering.
abstract: Photoresponsive micellar systems of 4-butylazobenzene-4'- (oxyethyl)trimethylammonium bromide (AZTMA) were examined with and without ethylbenzene using small-angle neutron scattering (SANS). Analysis of SANS profiles showed that an aqueous solution containing 5, 10, and 50 mM AZTMA forms prolate spheroids with a long radius (Ra) of 38 Å and a short radius (Rb) of 21 Å. In the 5 mM AZTMA solution, the concentration of micelles decreased upon UV light irradiation, while their size and shape remained almost unchanged. Subsequent visible light irradiation reversed the decrease and increased the number of micelles. In contrast, 10 and 50 mM AZTMA solutions showed that the number and long radius of the micelles decreased with UV light irradiation, while subsequent exposure to visible light irradiation restored them. For AZTMA micellar solutions equilibrated with excess ethylbenzene, the solubilized amount of ethylbenzene increased upon UV light irradiation due to enhanced swelling of the micelles with cis-AZTMA. This photoinduced uptake of the solubilizate has potential applicability for the collection and removal of hazardous oily substances.
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Masaaki
authors: M
authors: Akamatsu
authors: ‡School of Chemistry, F11, The University of Sydney, New South Wales 2006, Australia.
authors: Paul A
authors: PA
authors: FitzGerald
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Mayu
authors: M
authors: Shiina
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Takeshi
authors: T
authors: Misono
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Koji
authors: K
authors: Tsuchiya
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Kenichi
authors: K
authors: Sakai
authors: †Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan.
authors: Masahiko
authors: M
authors: Abe
authors: ‡School of Chemistry, F11, The University of Sydney, New South Wales 2006, Australia.
authors: Gregory G
authors: GG
authors: Warr
authors: ‡School of Chemistry, F11, The University of Sydney, New South Wales 2006, Australia.
authors: Hideki
authors: H
authors: Sakai
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D007536:Isomerism; D008027:Light; D008823:Micelles; D008956:Models, Chemical; D015394:Molecular Structure; D033363:Neutron Diffraction; D055668:Photochemical Processes; D053838:Scattering, Small Angle; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D001965:Bromides; D008823:Micelles; D013501:Surface-Active Agents; C004912:ethylbenzene