Low-concentration aqueous solutions of undecenoic acid and sodium undecenoate

The behaviors of low-concentration aqueous solutions of 10-undecenoic acid and its sodium salt were studied by several techniques. The acid does not have a critical micelle concentration, but gives an emulsion of very small droplets at (0.8-1) x 10(-4) mol dm(-3). The emulsion was clearly visible by eye at 0.002 mol dm(-3) The sodium salt has a stepwise aggregation process, giving premicellar aggregates at 0.023 +/- 0.008 mol dm(-3), which grow to form micelles at 0.117 +/- 0.007 mol dm(-3). The compositions of the solution and the micelles were also studied.