6533b835fe1ef96bd129ecdc
RESEARCH PRODUCT
Thermal diffusion of dextran in aqueous solutions in the absence and the presence of urea.
Rei SugayaBernhard A. WolfRio Kitasubject
chemistry.chemical_classificationAqueous solutionPolymers and PlasticsChemistryHydrogen bondAnalytical chemistryTemperatureThermodynamicsWaterBioengineeringDextransPolymerAtmospheric temperature rangeThermal diffusivityBiomaterialsDiffusionSolutionschemistry.chemical_compoundDextranMaterials ChemistryUreaUreaMacromoleculedescription
The Ludwig-Soret effect was studied for aqueous solutions of dextran in the temperature range 15T55 degrees C taking into account the effect of the addition of urea. In the absence of urea, the Soret coefficient S(T) changes sign; it is positive for T45.0 degrees C but negative for T45.0 degrees C. The positive sign of S(T) means that the dextran molecules migrate toward the cold side of the fluid; this behavior is typical for polymer solutions, whereas a negative sign indicates the macromolecules move toward the hot side. The addition of urea to the aqueous solution of dextran rises S(T) and reduces the inversion temperature. For 2 M urea the change in the sign of S(T) is observed at T = 29.7 degrees C and beyond that value S(T) is always positive in the studied temperature range. To rationalize these observations, it is assumed that the addition of urea leads to an opening of hydrogen bonds similar to that induced by an increase in temperature.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2006-01-19 | Biomacromolecules |