Distribution of segments for terminally attached poly(ethylene oxide) chains

• A theory for describing the equilibrium ethylene oxide (EO) segment distribution for terminally attached poly(ethylene oxide) (PEO) chains is presented. It is based on Scheutjens and Fleer's lattice model for polymer solutions in heterogeneous systems and a two-state model for the EO segments. The two-state model provides one explanation of the solubility gap of homogeneous PEO solutions. The segment distribution is examined as a function of temperature, grafting density, and curvature. The present theory predicts distributions, which cannot be reproduced with the use of temperature-dependent interaction parameters in a one-state model. Specifically, the segments tend to be more accumulated at the surface but also far away from the surface at the expense of the intervening transition region. Calculation on a model of a micelles formed by the nonionic surfactant C 12E 8 supports the experimental conclusions that the EO segments are preferentially accumulated nearby the hydrocarbon core and not completely extended into the water region.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Mathematical Models - Iterative Methods

Polymers - Solutions

Probability - Random Processes

Statistical Mechanics - Theory

Thermodynamics - Statistical Mechanics

Equilibrium EO Segment Distribution

Ethylene Oxide (EO)

Polyethylene Oxide Chains

Scheutjens Fleer Lattice Model

Segments Internal Degrees of Freedom

Polyethers

Publikations- och innehållstyp

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