Physicochemical formulation of ethoxylated octylphenol surfactants in microemulsion-oil-water systems

COLL 184

Nelson Márquez, nelsonm@reacciun.ve, Bélgica Bravo, belgicabravo@yahoo.es, Gerson Chávez, genrich2000@hotmail.com, Ana Beatriz Caceres, caceresana7@cantv.net, and Fredy Ysambertt, ysambertt@yahoo.com. Lab. Petroquímica y Surfactantes, Departamento de Química-Facultad de Ciencias, Universidad del Zulia, Maracaibo, 526, Venezuela
The partition coefficient of a surfactant between oil and water is related to the free energy of transfer from one phase to the other. The influence of temperature on the partition coefficient of octylphenol ethoxylate oligomers between oil and water is reported. The variation of the partition coefficient with formulation variables can be used as a yardstick for the concept of general formulation expression. The partitioning coefficient of ethoxylated octylphenol between water and oil varies with temperature in a way that can be predicted based on the free energy of transfer of a surfactant molecule from the oil to the water phase. This allows us to propose a numerical expression for the surfactant affinity difference (SAD) to render the concept of physicochemical formulation