Effect of DMSO Addition on the Hexagonal Phase of the System Triton X/Water

This research studied the role of DMSO in a binary system of Triton X and water in the hexagonal mesophase. One effect of DMSO addition, determined using polarized optical microscopy and small-angle X-ray scattering measurements, is to promote a decrease in the hexagonal to isotropic phase transition temperature, <i>T</i>_H-ISO, decreasing the range of temperatures of the hexagonal phase until the hexagonal phase completely disappears when DMSO is added up to 5.0 mol %. The periodicity and the lattice parameter of the hexagonal arrangement, calculated as a function of DMSO concentration, slight increased due to the insertion of DMSO molecules in the water region, causing a greater distance between the cylindrical micelles, while the radius of the apolar domains kept constant at 22 (1) Å.