Studies on the Activation Energies and the Mechanism of Electric Conductivity of W/O Type Microemulsions
SHEN Xing-Hai, WANG Wen-Qing , GU Guo-Xing (Department of Technical Physics, Peking University, Beijing, 100871)
Variations of activation energies (△E) with water content for microemulsions composed of SDS-alcohol (1-butanol-l-octanol)-heptane-water were determined. It is found that AS butanol system decreases slightly with the increase of water content, while that of pentanol system presents a maximum at its percolation threshold. For hexanol, heptanol and octanol systems, the activation energies exhibit rising trends before the limitations of added water. It is also found that the activation energy increases with the increase of the length of alcohol chain, which means that the longer the length of alcohol chain, the bigger the strength of the interfacial membranes of particles. Based on the above results, the mechanism of electric conductivity of W/O microemulsions is suggested, i. e. , cations' hopping through the membranes of particles among the inner water cores results in producing the electric conductivity.