FORMATION OF A LAMELLAR PHASE - REARRANGEMENT OF AMPHIPHILES FROM THEBULK ISOTROPIC-PHASE INTO A LAMELLAR FASHION

The dynamics of the formation of a lyotropic lamellar arrangement. of surfactant molecules has been studied by means of a contact experiment . Technical grade dodecylbenzenesulfonic acid (HDoBS) was brought into contact with water or an aqueous solution containing sodium hydroxide or sodium hydroxide plus sodium chloride. The phase penetration was f ollowed by light microscopy and freeze-fracture electron microscopy (F FEM). By the FFEM technique more insight has been obtained into the or dering process on a molecular level. The use of FFEM for such an appli cation has not been presented before. In combination with phase diagra ms, these techniques offered a mechanism for the formation of the lame llar phase, starting from the bulk surfactant situation. As a first st ep, water penetrates into bulk liquid isotropic HDoBS, thereby in pass ing inducing the lamellar order of surfactant molecules. Further matur ing of the lamellar phase strongly depends on the type of aqueous phas e offered.