The European Physical Journal E

, 39:86

Thermophoresis of cyclic oligosaccharides in polar solvents

  • Kazuya Eguchi
  • Doreen Niether
  • Simone Wiegand
  • Rio Kita
Regular Article
Part of the following topical collections:
  1. Non-isothermal transport in complex fluids

Abstract.

Cyclodextrins are cyclic oligosaccharides which are interesting as drug delivery systems, because they can be used as containers for pharmaceutical substances. We studied the Ludwig-Soret effect of \( \alpha\)-, \( \beta\)-, \( \gamma\)- and methyl-\( \beta\)-cyclodextrin in water and formamide by infrared thermal diffusion forced Rayleigh scattering (IR-TDFRS). In water the Soret coefficient, ST, of \( \alpha\)-, \( \beta\)- and \( \gamma\)-cyclodextrin increases with increasing temperature and shows a sign change from negative to positive around T = 35 °C, while ST of methyl-\( \beta\)-cyclodextrin is positive in the entire investigated temperature. In formamide ST-values of all cyclodextrins coincide and show a slight decrease with temperature. We discuss the obtained results and relate the ST-values to the different hydrogen bonding capabilities of the cyclodextrins and the used solvents. It turns out that the change of ST with temperature correlates with the partition coefficient, logP, which indicates that more hydrophilic substances show a more pronounced temperature sensitivity of ST. Additionally we obtained a surprising result measuring the refractive index contrast factor with temperature, \((\partial n/\partial T)_{c,p}\) of cyclodextrins in formamide, which might be explained by a complex formation between cyclodextrins and formamide.

Graphical abstract

Keywords

Topical Issue: Non-isothermal transport in complex fluids 

Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Kazuya Eguchi
    • 1
  • Doreen Niether
    • 2
  • Simone Wiegand
    • 2
    • 3
  • Rio Kita
    • 1
    • 4
  1. 1.School of ScienceTokai UniversityKanagawaJapan
  2. 2.ICS-3 Soft Condensed MatterForschungszentrum Juelich GmbHJuelichGermany
  3. 3.Chemistry Department - Physical ChemistryUniversity CologneCologneGermany
  4. 4.Micro/Nano Technology CenterTokai UniversityKanagawaJapan

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