Phase Behavior of Aqueous Mixtures of Hexaethylene Glycol Monododecyl Ether and Sodium Alkylsulfonates

Addition of low concentrations of sodium alkylsulfonates markedly changes the phase behavior of aqueous solutions of hexaethylene glycol monododecyl ether. Longer chain sulfonates raise the cloud temperature and lead to the formation of new high-temperature phases. One of these phases is colored when illuminated with white light and displays streaming birefringence, while another phase is statically birefringent. Long range order, as demonstrated by light scattering, builds up as the new phases are approached through neighboring micellar phases. It is likely that electrostatic micellar repulsions introduced by anionic head-groups act over longer distances than other relevant interactions and lead to the observed long range order.