Abstract
We present for the first time differential-scanning microcalorimetric measurements to investigate changes of the specific heat of a single-phase AOT(sodium di-2-ethylhexyl sulfosuccinate)/water/isooctane microemulsion. For a certain composition of the microemulsion two distinct peaks in the specific heat are observed. Peak position temperatures are close to and several degrees above the percolation temperature. We conclude that the first peak is due to the formation of a macroscopic droplet cluster (percolation threshold), whereas the second to the transition of the nanodroplet clusters to a bicontinuous structure.