Dielectric relaxation of the Kohlrausch-type in aqueous polymer solution

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Abstract
Micro‐Brownian motion of polymer chain in aqueous solution was clearly observed at first for poly(vinyl pyrrolidone) as a dielectric relaxation by a time domain reflectometry method which covers an extremely wide frequency region from 100 kHz–10 GHz. The dielectric response function observed is of the Kohlrausch‐type as expected for the chain motion, φ(t)=exp[−(t/τ l )β l ]. Concentration dependence of the relaxation time τ l at 25 °C is given by log τ l =−9.77−1.35/(c d −2.07), where c d is the polymer concentration (g/cc), and that of the coupling parameter β l is given by β l =−0.182c d +0.662. These dependences are characteristic features of the relaxation caused by the chain motion.