Slow Debye-type peak observed in the dielectric response of polyalcohols
Artikel i vetenskaplig tidskrift, 2010

Dielectric relaxation spectroscopy of glass forming liquids normally exhibits a relaxation scenario that seems to be surprisingly general. However, the relaxation dynamics is more complicated for hydrogen bonded liquids. For instance, the dielectric response of monoalcohols is dominated by a mysterious Debye-like process at lower frequencies than the structural alpha-relaxation that is normally dominating the spectra of glass formers. For polyalcohols this process has been thought to be absent or possibly obscured by a strong contribution from conductivity and polarization effects at low frequencies. We here show that the Debye-like process, although much less prominent, is also present in the response of polyalcohols. It can be observed in the derivative of the real part of the susceptibility or directly in the imaginary part if the conductivity contribution is reduced by covering the upper electrode with a thin Teflon layer. We report on results from broadband dielectric spectroscopy studies of several polyalcohols: glycerol, xylitol, and sorbitol. The findings are discussed in relation to other experimental observations of ultraslow (i.e., slower than the viscosity related alpha-relaxation) dynamics in glass formers.

behavior

susceptibility

clusters

relaxation

dynamics

liquids

dielectric relaxation

1-propanol

organic compounds

glass-forming liquids

monohydroxy alcohols

optical

dielectric polarisation

room-temperature

Författare

Rikard Bergman

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Helen Jansson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Jan Swenson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Journal of Chemical Physics

0021-9606 (ISSN) 1089-7690 (eISSN)

Vol. 132

Ämneskategorier

Fysik

DOI

10.1063/1.3294703