Oligo- and polyethylene glycols in water-in-oil microemulsions. A SANS study

The influence of oligo- and polyethylene glycols (PEG) on ionic aerosol-OT water-in-oil (w/o) microemulsions has been investigated by small-angle neut ron scattering (SANS). The scattering curves can be described with a model of polydisperse spheres, using an Omstein-Zernicke structure factor, regard less of the PEG relative molecular mass. The results obtained at a constant temperature difference from the percolation point indicate that the drople t structure is maintained, the core radius is decreased and the polydispers ity is increased with increasing PEG chain length. There is good evidence t hat long-chain PEGs induce aggregation of these droplets. The results suppo rt the model of polymer adsorption, which was deduced from the influence of PEGs on the percolation behaviour.