Rheology of styrene-butadiene diblock copolymers dissolved in selective solvent: Dependence on molecular dimension.

• Watanabe Hiroshi

  Department of Macromolecular Science, Faculty of Science, Osaka University

• Kotaka Tadao

  Department of Macromolecular Science, Faculty of Science, Osaka University

Abstract

The rheology of solutions of a series of styrene–butadiene diblock copolymers dissolved in a highly selective solvent, n-tetradecane, was examined in relation to the molecular dimension of the block copolymers. Micelles with precipitated S cores and dissolved B cilia are formed in the solution. Above a certain concentration and below a certain temperature, micelles in the solution are spontaneously arranged to form a regular three-dimensional array referred to as a macrolattice. Solutions having macrolattice structures exhibit nonlinear viscoelastoplastic flow, and those having no macrolattices exhibit linear viscoelastic flow. The critical concentration, at which transitions in rheology and morphology occur, may be predicted from the structural characteristics of the micelles, i.e., their size and number of molecules making up a micelle. The relationship of dynamic moduli and the molecular dimensions was examined in detail. The shorter the length of dissolved B blocks, the larger the storage modulus and the smaller the loss modulus. Two mechanisms, being the delayed relaxational motions of the dissolved B blocks and deformation of the macrolattice itself, seem responsible for the stress in the solution. The mechanism of the lattice disordering caused by heat is also discussed. A diffuse interphase between the S core and B cilia seems to play a key role in the lattice disordering.

Journal

• Polymer Journal

  Polymer Journal 14 (9), 739-747, 1982

  The Society of Polymer Science, Japan

Keywords

• Styrene–Butadiene Diblock Copolymer
• Block Copolymer Solution
• Solution Rheology
• Microphase Separation
• Superstructure
• Liquid Crystalline System
• Nonlinear Viscoelastoplasticity
• Plastic Flow

Details

• CRID: 1390001206290086528
• NII Article ID: 130004428438
• NII Article ID: 30001924476
• DOI: 10.1295/polymj.14.739
• COI: 1:CAS:528:DyaL38XlvFyrtLs%3D
• ISSN: 13490540
• ISSN: 00323896
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed