Solution properties of a hydrophobically modified polymer

Research output: ThesisDoctoral Thesis (compilation)

Abstract

The influence of hydrophobic modification on solution properties of water-soluble polymers in the semi-dilute regime have been studied. The nonionic ethyl(hydroxyethyl)cellulose (EHEC) and its hydrophobically modified analogue (HM-EHEC) are used as model substances. Interactions between the polymer molecules in solution and a third component are investigated, and in particular the influence of the surfactant sodium dodecylsulfate (SDS). The polymer/SDS complex formation is investigated by using several techniques (phase behaviour, rheology, calorimetry, DS- sensitive electrode, NMR, and light scattering and fluorescence techniques). This combination of methods gives thermodynamic information on the complex formation, as well as information about the dynamics of the polymer/surfactant complex. In a binary, semi-dilute, HM-EHEC solution the hydrophobic tails associate in clusters with an average of ten tails. These 'pre-formed' micelles act as nucleation sites for other molecules that contain hydrophobic moieties. The number of mixed micelles, and the strengths of the inter polymeric bonds which they give rise to, control both microscopic properties (as chain motions) and macroscopic behaviour (as rheology and phase behaviour). Experimental phase studies with hexanol as a third component were compared with model calculations in a modified Flory-Huggins approach. By assuming that hydrophobic modification causes enhanced association with the polymer semi-quantitative agreement was found. The associative phase separation that is usually observed in mixtures of two oppositely charged polyelectrolytes is effectively prevented by hydrophobic modification of both polyelectrolytes; a highly viscous phase is formed.

Details

Authors
  • Krister Thuresson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry

Keywords

  • sodium dodecylsulfate, surfactants, fluorescence, light scattering, NMR, rheology, cloud point, phase behaviour, polyelectrolytes, ethyl(hydroxyethyl)cellulose, hydrophobically modified, water soluble polymers, aggregation number, association, Physical chemistry, Fysikalisk kemi
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • [unknown], [unknown], Supervisor, External person
Award date1996 May 25
Publisher
  • Physical Chemistry 1, Lund University
Print ISBNsISBN91-628-2088-5
Publication statusPublished - 1996
Publication categoryResearch

Bibliographic note

Defence details Date: 1996-05-25 Time: 10:15 Place: lecture hall C, Chemical Center, Lund External reviewer(s) Name: Leibler, Ludwik Title: [unknown] Affiliation: Elf-Atochem, UMR CAL, 95 rue Danton, B. P. 108, 92303 Levallois-Perret cedex, France ---

Related research output

Thuresson, K., Söderman, O., Hansson, P. & Wang, G., 1996, In : Journal of Physical Chemistry. 100, 12, p. 4909-4918

Research output: Contribution to journalArticle

Thuresson, K., Nilsson, S. & Lindman, B., 1996, In : Langmuir. 12, 2, p. 530-537

Research output: Contribution to journalArticle

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