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

Abstract

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