Dielectric spectroscopy as a probe for dynamic properties of compacted smectites

The micro-dynamics of water and ions in two types of clays (montmorillonite and hectorite) was investigated with broadband dielectric spectroscopy (40 Hz to 5 GHz). Four to five relaxations were observed depending on the relative humidity, the clay type and the nature of the compensating counter-ion (Na+ or Cs+). A tentative assignment of the relaxations to physical mechanisms is proposed.