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Equilibrium and dynamic aspects of end-attached diblock and triblock copolymer chains

  • C. TOprakcioglu
  • L. Dai
  • M. A. Ansarifar
  • M. Stamm
  • H. Motschmann
Chapter
Part of the Progress in Colloid & Polymer Science book series (PROGCOLLOID, volume 91)

Abstract

We report results on adsorbed layers of polystyrene (PS)-polyethylene oxide (PEO) diblock and PEO-PS-PEO triblock copolymers at the solid/liquid interface. The volume fraction profiles of the adsorbed PS-PEO diblock copolymers at the the quartz/toluene interface determined by neutron reflectometry are consistent with a parabolic profile as predicted by theory. Ellipsometry was used to investigate the adsorption kinetics of PS-PEO diblock copolymer chains on SiO2 from toluene. The results show a rapid diffusion-controlled process, characterized by a linear increase in the adsorbed amount with the square-root of time, at the early stages of adsorption, while at late times adsorption is slow and appears to be governed by an exponential time behavior. Studies of the PEO-PS-PEO copolymer, using the surface-force apparatus, reveal conformational rearrangements for the adsorbed triblock chains between mica surfaces. When two such surfaces are in close proximity to each other, triblock chains originally adsorbed in a “loop” conformation may open into a “bridge” conformation with both PEO blocks of a given chain adsorbing onto opposing mice surfaces. This is indicated by the appearance of clearly detectable attractive forces and their evolution with compression-decompression cycles. The time evolution of these forces reflects the dynamics of the rearrangement of chains between the two surfaces.

Key words

Adsorption block copolymers elliposometry neutron reflectometry surface-force apparatus 

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Copyright information

© Dr. Dietrich Steinkopff Verlag GmbH & Co. KG 1993

Authors and Affiliations

  • C. TOprakcioglu
    • 3
    • 1
  • L. Dai
    • 3
  • M. A. Ansarifar
    • 3
  • M. Stamm
    • 2
  • H. Motschmann
    • 2
  1. 1.Institute of Food Research, AFRCNorwichEngland
  2. 2.Max-Planck Institute fur PolymerforschungMainzFRG
  3. 3.Cavendish Laboratory, PCSUniversity of CambridgeCambridgeEngland

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