Grafted polymers under the influence of external fields

J. F. Marko*, A. Johner, C. M. Marques

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The structure of grafted polymer "brushes" may be profoundly modified by the action of "external fields"-local shifts in chemical potential due to, e.g., interfacial effects at the grafting surface. We discuss the strong-stretching limit of the self-consistent mean-field theory for a brush exposed to an arbitrary external potential, a simple scaling law for the brush height arises in the case where the external field pushes monomers towards the surface. In contrast, repulsive interactions can lead to quot;exclusion zonesquot; or regions from which polymer ends are repelled, leading to a breakdown of the simple scaling formula. We exactly solve the self-consistent theory of the brush in a repulsive square well where an exclusion zone always appears. Our results describe a brush in the case where a thin layer of one component of a binary solvent that is a worse solvent for the polymer than is the bulk mixture wets the grafting surface. We also discuss the effects of thermal fluctuations and chain polydispersity on our results, and estimate the effects of various interfacial phenomena on the brush structure.

Original languageEnglish (US)
Pages (from-to)8142-8153
Number of pages12
JournalThe Journal of Chemical Physics
Volume99
Issue number10
DOIs
StatePublished - Jan 1 1993

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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