Effects of α-, β- and γ-cyclodextrins on the critical micelle concentration of sodium dodecyl sulfate micelles

The effects of alpha-, beta- and gamma-cyclodextrins, CDs, on the formation of sodium dodecyl sulfate micelles have been investigated by employing a conductometric method under acidic conditions. The simultaneous presence of H+ ions and Na+ ions makes the specific conductivity of the solution to follow a Z-shaped curve, which can be rationalized by considering ion exchange effects. Any of the CDs employed inhibits micelle formation as indicated by the observed linear increase in the apparent critical micelle concentration upon increasing [CD], the degree of inhibition following the order alpha-CD < beta-CD < gamma-CD. (C) 2004 Elsevier B.V. All rights reserved.