Characterization of lecithin cylindrical micelles in dilute solution

An extensive study of the polymerlike properties in dilute solutions of lec ithin cylindrical micelles, with trace amounts of water, in isooctane is pr esented. In contrast to the current picture that this system behaves as a s olution of wormlike polymers, we find that it is best described as a soluti on of rodlike micelles. This finding is based on the combined results of vi scometry, electrooptic birefringence, dielectric spectroscopy, static and d ynamic light scattering, and dynamic sedimentation. Also, the size of the m icelles seems to be independent of the concentration, whereas a strong depe ndence is predicted for polymerlike micelles. There is a rather abrupt chan ge in micellar size at low concentration, which can be attributed to a sphe re-to-rod transition. At high water content further evidence is found for t he percolation of the micelles into a connected network, as has been sugges ted by us recently.(8)