Formation of oil-in-polyethylene glycol/water emulsions

Oil-in-polyethylene glycol/water emulsions were prepared using various PEG'S and various ratios of water to PEG. It was found that for all PEG'S studied, droplet size decreased with decreasing water concentration, until a fast phase separation was observed. The water concentration in which the phase separation occurred was dependent on the m.w. of the PEG. At constant water concentrations in the external phase, the finest droplets were obtained with the high m.w. PEG'S. The effect of PEG concentration and m.w. on the cloud point of the surfactant, Tween 80, was studied. The reduction of cloud points, and hence the apparent HLB is correlated with the droplet sizes, and phase separation in the emulsions.