Zeta Potential of Porous Materials
Propagation of ultrasound through a wetted porous matrial generates electric responce that is known as electroseismic effect. It can be characterised as high frequency electroacoustic streaming curreent. There are several papers dedicated to theoretical and experimental studies of this effect. It turns iut that it can be used for characterizing porous materials, in particular; zeta potential.
Instrument DT -350 is capable of measuring electroseismic current, amplitude and phase. It employs the same Zeta potential probe that is part of the DT-300 and 310 models for characterizing zeta potential of concentrated dispersions and emulsions.
Calculation of zeta potential from seismoelectric current would require information on porosity. It would be very convinient to use porosity measurement that employs high frerquency AC electric field, since it is already part of the seismoelectric measurement. That is why DT-350 is equiviped with DTI aqueous conductivity probe that functions at 3 MHz. Details of the porosity measurement are described in the text that is linkerd to the Model DT-900.