Pa. Cirkel et al., BRANCHING AND PERCOLATION IN LECITHIN WORMLIKE MICELLES STUDIED BY DIELECTRIC-SPECTROSCOPY, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 57(6), 1998, pp. 6875-6883
Lecithin water-in-oil microemulsions have been shown to form long poly
merlike micelles. Dielectric spectra of this system are characterized
by two dispersions. The high frequency dispersion, related to the head
-group rotation of the lecithin molecule, displays a different depende
nce on water addition in the same two regimes that show up differently
in the dynamics measured with several other techniques. The low frequ
ency dispersion is due to a polymeric Rouse/Zimm type mode, which abov
e a certain concentration starts to decrease and shows the characteris
tics of percolation. Ln the high water regime the decrease of the rela
xation time is accompanied by an increase in conductivity, whereas in
the low water regime the conductivity decreases. These data are interp
reted in terms of concentration induced percolation and water induced
coalescence into a connected network.