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Characterization of a PEO-PPO-PEO block copolymer system

  • K. Schillén
  • O. Glatter
  • W. Brown
Conference paper
Part of the Progress in Colloid & Polymer Science book series (PROGCOLLOID, volume 93)

Abstract

The investigated EO27-PO39-EO27 triblock copolymer, Pluronics P-85, is a nonionic surface-active agent which has a monomeric molecular weight of 4600, of which 500% corresponds to the PEO component. P-85 exist in complex states of aggregation in aqueous solution. Monomers, micelles and larger aggregates (clusters) coexist at lower concentrations in relative proportions which depend on temperature. The micelles are composed of a core of the water-insoluble PPO-block with a swollen shell of PEO-endblocks, having a hydrodynamic radius of 75 Å. The monomers have a hydrodynamic radius of 18 Å. At higher temperatures and concentrations, the micelles are close-packed in a body-cente-red-cubic (b.c.c.) liquid crystalline phase which is solid-like and glass-clear. At even higher temperatures this gel of micelles “dissolves” again. For structural (internal) information on the monomer, the micelle, and to study the interacting micelles and the gel, small-angle x-ray-scattering measurements and dynamic light-scattering measurements have been made in the concentration range 1 to 25% (w/w) with the temperature range 5 to 70°C. The micellization was detected clearly by ultrasound velocimetry measurements. To characterize the viscosity of the gel (cubic phase) advanced densimetry was performed.

Key words

Triblock copolymer micelle gel small-angle x-ray scattering ultra-sound velocimetry densimetry 

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Copyright information

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

Authors and Affiliations

  • K. Schillén
    • 2
    • 1
  • O. Glatter
    • 2
  • W. Brown
    • 1
  1. 1.Department of Physical Chemistry University of UppsalaSweden
  2. 2.Institute of Physical ChemistryUniversity of GrazGrazAustria

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