Surface potential measurement: a tool for complex permittivity determination in the very low frequency range

The method presented gives the opportunity to calculate complex permittivity in the low frequency region and to study interfacial phenomena. The approach is based on the measurement of the surface potential of the studied dielectric material. Indeed, it appears that a direct relationship exists between their evolution and the polarisation current, and that the Fourier transform of these evolutions is itself directly related to the real and the imaginary part of the permittivity within the range of 10/sup -4/ to 1 Hz.