Dielectric properties of polystyrene-CCTO composite

The control of the dielectric properties of polymer composites is a relevant tool to synthesize a material to a specific industrial application. Polystyrene (PS) is a suitable host because it is readily available, and is easy to cast into desired shapes, maintaining the mechanical integrity of the matrix. CaCu3Ti4O12 (CCTO) is a well-known high dielectric constant material, very useful for capacitors and memory devices. In this work, we studied the dielectric properties of the composite PS-CCTO, in the frequency range 10 Hz to 100 kHz, for CaCu3Ti4O12 grains concentrations up to 64% by volume. Different mixture laws were used to fit the data: Hanai, Wiener, Maxwell-Wagner, Kraszewsky, Looyenga and Generalized Looyenga. The last one presents the best results. The calculated exponent of this law was then correlated with the shape particles observed by scanning electron microscopy. Finally, using Generalized Looyenga law, we can carefully select the adequate CCTO concentration in order to tailor the desired behavior, producing interesting composites for potential applications. (C) 2008 Elsevier B.V. All rights reserved.