Insights into sample preparation for dielectric response measurements

The dielectric response of a series of polystyrene latices was measured to investigate the experimental limitations of the technique. Measurements were initially conducted with a four-electrode cell at low frequency and a two-electrode cell at high frequency. These measurements demonstrated that the dielectric response was not technique dependent. Various methods of sample preparation were tested to observe if the method of preparation affected the measurement outcome. It was found that the measured spectra were very dependent on the method on sample preparation and sample history. Some methods of sample preparation gave spectra with very large magnitudes typical of the observations that have lead others to modify theory with the inclusion of conduction within the Stern plane. The method that gave the most consistent results was centrifugation, serum replacement and re-dispersion with a sample volume fraction of 10–20 vol.%.