Aggregate Structure and Dynamic Percolation in Microemulsions

This contribution deals with a special class of soft matter systems called microemulsions. They are mixtures of oil and water stabilized with a surfactant. The stabilisation is achieved through the reduction of interfacial tension by the amphiphilic surfactant. They thus consist of oil and water phases separated by a surfactant layer. The nanoscopic structure of these phases, in particular that of spherical nano droplets, is analysed in this chapter. The impact of temperature and mixing ratio of the constituents is shown. The fascinating phenomenon of dynamic droplet percolation and aggregation near a temperature induced phase separation are discussed. Microemulsions provide an excellent model system for the investigation of confinement effects on molecules. Conversely these guest molecules modify structural and dynamical properties of the microemulsion. This may even lead to the formation of transient networks with short time gel-like and long time self-diffusion dynamics of droplets.