Physical chemical studies of short-chain lecithin homologues. IV. A simple model for the influence of salt and the alkyl chain length on the micellar size

A simplified association model for micellisation is presented. In this model two features are incorporated; (a) There is an optimum for the change of the standard free energy per monomer upon micellisation at a certain association number. (b) At higher association numbers this free energy change becomes constant. The resulting equations for the dependence of the average micellar weight on the concentration are used to explain the experimetitally observed effects of a salting-out agent (NaCl) and of the alkyl chain length of dihexanoyl-, diheptanoyl- and dioctanoyl-lecithin.