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 wer e 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 t he measurement outcome. It was found that the measured spectra were very de pendent on the method on sample preparation and sample history. Some method s 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 Stem plane. The method that gave the most consiste nt results was centrifugation, serum replacement and re-dispersion with a s ample volume fraction of 10-20 vol.%. (C) 2001 Elsevier Science B.V. All ri ghts reserved.