STRUCTURAL EVOLUTION AND MICROSCOPIC INTERACTIONS IN A 3-COMPONENT AMPHIPHILIC MICROEMULSION SYSTEM

Structures and interaction parameters of a three-component amphiphilic microemulsion system consisting of n-decane, water, and an amphiphile AOT (sodium-di-2-ethylhexylsulfosuccinate) have been studied by means of small angle neutron scattering. The scattering curves are fitted w ith Teubuer and Strey's formula, from which three structural parameter s are extracted; the average periodic distance D between the oil and w ater, the structural correlation length xi, and the area a(H) per amph iphile molecule. The same data are further examined in terms of Gomppe r and Schick's formula, from which three interaction parameters are ob tained; the strength of segregation J/T among the oil and water, the a mphiphilicity L/T of the amphiphile toward the oil and water, and the critical surfactant volume fraction phi(s)(c). These interaction param eters have right order of magnitudes and their implications to structu ral evolution are discussed. (C) 1996 American Institute of Physics.