An investigation into the low-frequency dielectric response of polyethylene glycols

Abstract

The dielectric response of a series of polyethylene glycols (PEGs) in the molecular weight range 3400–20 000 has been studied using low-frequency dielectric spectroscopy. In the molten state, a Maxwell-Wagner response was seen, indicating a conducting bulk in series with a barrier layer of high capacitance. The high-frequency conductance was shown to be activated, with a higher activation energy being seen for PEG 3400 than for the other three molecular weight samples, all of which possessed similar values. On solidification, the samples showed spectra which corresponded to a high-frequency response of comparatively small magnitude with a larger response being observed as the frequency was lowered. The low-frequency conductance decreased with chain length, although no other relationship was found between the components of the dielectric response and the molecular weight.