Dynamics of Water in a Polymer Matrix Studied by a Microwave Dielectric Measurement

Abstract

Dielectric measurements on water mixtures of polymers such as poly(vinylpyrrolidone) (PVP), poly(ethylene glycol) (PEG), poly(vinyl methyl ether) (PVME), poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), poly(ethylenimine) (PEI), and poly(allylamine) (PAlA) were performed over a frequency range from 300 MHz to 15 GHz at 25 °C. Dielectric dispersion and absorption curves related to the orientational motion of water can be described well by the Cole−Cole equation. The distribution of the relaxation time is interpreted by the variation of the water structure. The logarithmic plot of the relaxation time against the parameter for the distribution of the relaxation time suggests two groups of polymers. One group contains nonelectrolyte polymers and another contains electrolyte polymers and PVA. This result implies that water structures in the mixtures of the former group are more uniform and stable than that in the mixtures of the latter group.

Dynamics and Glass Transition of Aqueous Solutions of Molecular Liquid, Polymer, and Protein Studied by Broadband Dielectric Spectroscopy

“…9.2, water relaxation exhibits a symmetric shape on both the highand low-frequency sides of the loss peak above T s , as shown in Fig. 9.3b [39,40,55,[58][59][60]62]. The shape of the ν-relaxation in solutions of high-molecular-weight solutes is different from that for solutions of low-molecular-weight solutes, although water molecules form hydrogen bonds with high-molecular-weight solutes.…”

“…In solutions containing solutes with a low molecular weight, such as alcohols (molecular weight, M W 100), the observed relaxation curve was asymmetric with respect to the loss peak above the separation temperature T S [39,40,55,[59][60][61], as shown in Fig. 9.3a.…”

“…Here, we call it ν-relaxation [55], ν being the initial letter of νερo, which means water in Greek. It was shown that ν-relaxation is the primary dielectric relaxation of water observed in various aqueous solutions at around room temperature, and the shape of the ν-relaxation spectrum depends on the molecular weight of the solute [39,40,55,[58][59][60][61][62].…”

Dielectric relaxation and hydrogen bond interaction study of diol-water mixtures

“…Dielectric relaxation studies of aqueous diol using Time Domain Reflectometry (TDR) technique have been done by Shinyashiki et al [7] to confirm the solute-solvent interaction and dynamics behaviour of water [7][8][9][10]. Extensive dielectric relaxation studies were carried out in the frequency range from 10MHz to 10GHz on the associating molecules for their molecular conformations [11][12][13].…”

Chain length effect on dynamical structure of poly (vinyl pyrrolidone)-polar solvent mixtures in dilute solution of dioxane studied by microwave dielectric relaxation measurement

“…The conformation of the polar solvents and their molecular dynamics in polymer matrix are the most important and challenging problems in liquid state physics. The molecular size dependence of dielectric properties for two-component system shows various characteristic properties, which have been the subject of a large number of investigations [2][3][4][5][6][7][8][9][10][11][12][13][14].…”