title: Flower micelle of amphiphilic random copolymers in aqueous media.
abstract: The structure of the flower micelle formed by an amphiphilic random copolymer, sodium (2-acrylamido)-2-methylpropanesulfonate and N-dodecylmethacrylamide p(AMPS/C12), in 0.05 M aqueous NaCl was investigated by fully atomistic molecular dynamics simulation as well as by light scattering, and the results were compared with the flower micelle model of the minimum loop size, recently proposed by Kawata et al. [Macromolecules 2007, 40, 1174-1180]. After a sufficiently long simulation time, simulated p(AMPS/C12) chain with the degree of polymerization of 200 and C12 content of 50 mol % formed a unicore micelle, of which radius of gyration was much smaller than the AMPS homopolymer with the same degree of polymerization. The simulated micellar structure was analyzed in terms of density distribution functions for dodecyl groups, the main chain, and sulfonate groups as functions of the radial distance r from the center of mass of dodecyl groups. Only dodecyl groups exist at r less, similar 1.5 nm, and the main chain and sulfonate groups distribute in the range of r between 1.5 and 3.5 nm, but there were dodecyl groups coexisting with the main chain and sulfonate groups beyond r = 1.5 nm. All these structural features, as well as hydrodynamic radius data for p(AMPS/C12) with C12 contents higher than ca. 20 mol % obtained by light scattering, agreed with the predictions of the flower micelle model of the minimum loop size.
authors: Genomic Science Laboratories, Dainippon Sumitomo Pharma Co., Ltd., 33-94 Enoki, Suita, Osaka 564-0053, Japan.
authors: Yukio
authors: Y
authors: Tominaga
authors: Mari
authors: M
authors: Mizuse
authors: Akihito
authors: A
authors: Hashidzume
authors: Yotaro
authors: Y
authors: Morishima
authors: Takahiro
authors: T
authors: Sato
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D017738:Alkanesulfonic Acids / Q000737:chemistry; D008823:Micelles; D056004:Molecular Dynamics Simulation; D011108:Polymers / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000178:Acrylamides; D017738:Alkanesulfonic Acids; D008823:Micelles; D011108:Polymers; D014867:Water; C068559:propylsulfonic acid; C045985:methacrylamide