Effect of temperature on poly(ethylene oxide) chains in aqueous solution. A viscometric, 1H NMR and Raman spectroscopic study

Abstract

A combination of viscometry, Raman scattering and ¹H NMR measurements has been used to study the effect of temperature changes on the properties of solutions of poly(ethylene oxide) in H₂O or D₂O. The viscosity data show that the overall dimensions of the polymer chains decrease with increasing temperature, while the Raman spectra indicate a simultaneous decrease in chain helicity. Polymer ¹H NMR spin–lattice relaxation times in D₂O are consistent with a mechanism in which small segments of the chain reorient at a rate controlled by the solvent viscosity up to a temperature of ca. 80 °C.