CE and asymmetrical flow-field flow fractionation studies of polymer interactions with surfaces and solutes reveal conformation changes of polymers

Joanna Witos, Erno Karjalainen, Heikki Tenhu, Susanne K. Wiedmer (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

Amphiphilic diblock copolymers consisting of a hydrophobic core containing a polymerized ionic liquid and an outer shell composed of poly(N-isoprolylacrylamide) were investigated by capillary electrophoresis and asymmetrical flow-field flow fractionation. The polymerized ionic liquid comprised poly(2-(1-butylimidazolium-3-yl)ethyl methacrylate tetrafluoroborate) with a constant block length (n = 24), while the length of the poly(N-isoprolylacrylamide) block varied (n = 14; 26; 59; 88). Possible adsorption of the block copolymer on the fused silica capillary, due to alterations in the polymeric conformation upon a change in the temperature (25 and 45 °C), was initially studied. For comparison, the effect of temperature on the copolymer conformation/hydrodynamic size was determined with the aid of asymmetrical flow-field flow fractionation and light scattering. To get more information about the hydrophilic/hydrophobic properties of the synthesized block copolymers, they were used as a pseudostationary phase in electrokinetic chromatography for the separation of some model compounds, that is, benzoates and steroids. Of particular interest was to find out whether a change in the length or concentration of the poly(N-isoprolylacrylamide) block would affect the separation of the model compounds. Overall, our results show that capillary electrophoresis and asymmetrical flow-field flow fractionation are suitable methods for characterizing conformational changes of such diblock copolymers.

Original languageEnglish
Pages (from-to)2495-2505
Number of pages11
JournalJournal of Separation Science
Volume43
Issue number12
DOIs
Publication statusPublished - 2020
MoE publication typeA1 Journal article-refereed

Keywords

  • Amphiphiles
  • Capillary electrophoresis
  • Conformational transition
  • Field flow fractionation
  • Hydrodynamic radius
  • Hydrodynamics
  • Hydrophilicity
  • Hydrophobicity
  • Ionic liquids
  • Phase separation
  • Polymer chain conformation
  • Polymer chain length
  • Zeta potential (CE and asym. flow-field flow fractionation studies of polymer interactions with surfaces and solutes reveal conformation changes of polymers)
  • Critical solution temperature (upper
  • CE and asym. flow-field flow fractionation studies of polymer interactions with surfaces and solutes reveal conformation changes of polymers)
  • Fractionation
  • Diblock
  • Copolymer

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