8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P6.30Fri 911:10-14:00Nascent nanoemulsions from microemulsion dilutionRamon Pons, 1 Imma Carrera, 1 and Jaume Caelles 11 IQAC-CSIC, Jordi Girona 18-26, 08034, Barcelona, SpainSurfactant structures in the nanometer range are present in thermodynamically stable systems suchas micelles, microemulsions and liquid crystals. However, thermodynamically unstable systemscan also have dimensions in the nanometer scale range. These soft matter nanostructures willevolve with time and their characteristics will depend on their history. It is of particular interestthe formation of miniemulsions (also known as finely dispersed emulsions and nanoemulsions)because of their low surfactant content and good stability. In this context we have investigated thedynamics of miniemulsion formation by diluting a microemulsion with excess water. Efforts havebeen made to obtain reproducible systems. We have investigated the first few seconds of miniemulsionformation by following the SAXS spectra with a home made flux set up that allows to performmeasurements at an initial time as short as 0.2 s.. Additional information on the system come fromthe viscosity of the mixtures measured with an in line home made device that allows the viscosityto be measured short after mixing using the same conditions as for the SAXS measurements. Theresults are compared with point cryo-TEM observations in conditions close to the ones observedby SAXS. Strong dynamic and salt effects have been observed on the viscosity of the mixtures. Atshort mixing times the viscosities are higher than after some seconds by a factor of 2-5 while theuse of salt in the dilution medium reduces the final viscosity by factors down to 10 times.30