1. Micellar aggregation in blends of linear and cyclic poly(styrene-b-isoprene) diblock copolymers
- Author
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Redouane Borsali, Nadia Ouarti, Jean-Luc Putaux, Roberto Lazzaroni, Michel Schappacher, Alain Deffieux, Edson Minatti, Pascal Viville, Univ Mons, Belgique, Serv Chim Mat Nouveaux, Université de Mons (UMons), Univ Fed Santa Catarina, Dept Quim, Univ Fed Santa Catarina, Laboratoire de Chimie des polymères organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Université Sciences et Technologies - Bordeaux 1-Institut de Chimie du CNRS (INC), Team 1 LCPO : Polymerization Catalyses & Engineering, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Centre de Recherches sur les Macromolécules Végétales (CERMAV), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
SELECTIVE SOLVENTS ,WORMLIKE MICELLES ,Materials science ,HOMOPOLYMER BLENDS ,ORDERED STRUCTURE ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Micelle ,Styrene ,chemistry.chemical_compound ,EXCLUDED-VOLUME INTERACTIONS ,PHASE-EQUILIBRIA ,Dynamic light scattering ,BLOCK-COPOLYMER ,Polymer chemistry ,Electrochemistry ,Copolymer ,General Materials Science ,Thermal stability ,ComputingMilieux_MISCELLANEOUS ,Spectroscopy ,SMALL-ANGLE NEUTRON ,Molar mass ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,LIGHT-SCATTERING ,0104 chemical sciences ,[CHIM.POLY]Chemical Sciences/Polymers ,chemistry ,Chemical engineering ,Transmission electron microscopy ,Volume fraction ,0210 nano-technology ,FORMING COPOLYMERS - Abstract
International audience; The morphology of micelles formed from blends of linear and cyclic poly(styrene-b-isoprene) (PS-b-PI) block copolymers has been investigated in solution using dynamic light scattering (DLS) and in thin solid deposits by atomic force microscopy (AFM) and transmission electron microscopy under cryogenic conditions (cryo-TEM). Micelles of the pure cyclic PS290-b-PI110 copolymers are wormlike cylindrical objects built by unidirectional aggregation of 33 nm wide sunflower micelles, while the linear block copolymer having the same volume fraction and molar mass forms spherical micelles 40 nm in diameter. The DLS, AFM, and cryo-TEM results consistently show that the addition of the linear copolymer (even for amounts as low as 5% w/w) to the cyclic copolymer rather favors the formation of spherical micelles at the expense of the cylindrical aggregates. Those results clearly show that the linear block copolymer chains can be used to stabilize the thermodynamically unstable elementary sunflower micelle. The thermal stability of the micelles (from the pure copolymers and from the blends) has been examined in solid deposits with in situ AFM measurements. Coalescence starts at about 70 degrees C, and the surface roughness shows a two-step decrease toward a fully homogeneous and flat structure.
- Published
- 2005
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