Dielectric Properties of Nitrocellulose - Water Gels

Abstract

THE influence of interphasial polarization processes on the dielectric behaviour of aqueous dispersions has been frequently discussed. In earlier communications^1,2, I directed attention to a striking effect of such a process, consisting of an extremely pronounced and broad dispersion region in the low-frequency zone, characterized by a rise in permittivity of the order of 100,000 under maximal conditions. The exact nature of this process has not yet been established. It was thought that the sorbed water might exhibit co-operative orientation, although this remains questionable in the absence of theoretical support. While this work was mainly on coarser systems, it was pointed out that the effect is an important factor in the dispersion found in systems of colloidal and macromolecular structure³, a particular study² being made of gelatin gels in support of this view. This work has now been extended to nitrocellulose gels, in which we have found a strongly developed low-frequency dispersion region, presumably of this same nature. The gels were measured in the form of membranes placed in aqueous solution, a procedure which has certain distinct experimental advantages.