Effects of structural variations on non-ionic surfactants on micellar properties and solubilization: surfactants containing very long hydrocarbon chains.

Polyoxyethylene mono-ethers of dotriacontanol (C32E41) and 4,9-dimethyltritriacontanol (C35E40) have been synthesized. The micellar weights in water at 298K were 4.82 x 10(5) and 5.90 x 10(5), the aggregation numbers 212 and 260, and the levels of hydration 290 and 283 mol water mol-1 surfactant, respectively. The solubilization of azobenzene, cortisone acetate, griseofulvin, sulphadiazine, phenylbutazone, betamethasone, tolbutamide, and menaphthone was studied in 2% solutions of the above surfactants. The presence of large micelles did not result in increased solubilization; C32E41 and C35E40 had a lower solubilizing capacity than that of cetomacrogol.