PRETRANSITIONAL HEAT CAPACITY NEAR THE LOWER CONSOLUTE POINT OF NONIONIC SURFACTANT SOLUTIONS

Abstract

The results of precision heat capacity measurements near the lower consolute point in aqueous solutions of non-ionic surfactants n-dodecyl hexaethylene glycol monoether (C12E6), C10E6, and C12E8, are reported. These surfactants form homogeneous single phase micellar solutions below the lower consolute point, Tc. The pretransitional specific heat in the homogeneous phase below Tc is found to grow with temperature and exhibits a power-law divergence. Analysis of the data obtained for the three systems reveals that the specific heat exponent, α=-αR/(1-αR)≅0.5, gives credence to mean field behavior.