Abstract:

The transport properties near the percolation temp. threshold in the ternary H2O-in-oil microemulsion stabilized by ionic surfactant was studied by measuring the self-diffusion coeffs. of all the constituents of the microemulsion, and the cond. at 10-40°. It can be conjectured that 2 different transition mechanisms of the charge carriers in this temp. region may take place. These may be attributed to either the transfer of counterions from 1 droplet to another through H2O channels or hopping of surfactant ions from droplets within clusters. The cond. and dielec. polarization below the percolation threshold is mainly due to the motion of counterions via H2O channels within the droplet clusters and not a charge-hopping mechanism at the surfactant interface. Above the percolation threshold the latter mechanism appears, connected with migration of surfactant mols. from droplet to droplet within a percolation cluster. The 1st mechanism still dominates. [on SciFinder(R)]