Contents I. Introduction
It is well known that polymer nanocomposites (NCs), in which only small quantity of nm-sized inorganic fillers are dispersed uniformly, have much better mechanical, thermal, and gas barrier properties, than the neat polymers or conventional composites with -sized fillers [1]–[3]. Therefore, polymer NCs are already used in many industrial fields, taking various forms such as automobile parts, food wrapping sheets, plastic bottles, and the like [1], [2]. Recently, it is reported in many papers [4]–[16] that polymer NCs also have better dielectric properties than conventional polymers. Based on the assumption that filler/resin interfaces with an enormously large total area should play an important role, several mechanisms have already been proposed to explain improved dielectric properties [13]–[16]. However, roles of nanofillers and their interfaces have not been fully understood yet for each dielectric material. Therefore, the effects of nanofillers and their interfaces on the molecular motion and carrier transport in polyamide-6 NCs are discussed in the present paper, through detailed analyses of their complex permittivity spectra.
