Marginalism, quasi-marginalism and critical phenomena in micellar solutions

Abstract

The observed nonuniversal critical behaviour of some micellar solutions is interpreted in terms of quasi-marginalism,i.e. the presence of a coupling which scales with an exponent very close to the spatial dimensionality. This can give rise to a preasymptotic region with varying effective critical exponents with a final crossover to the Ising ones. The reduced crossover temperature is estimated to be below 10−6. The exponents β and γ measured in C12E5 are in good agreement with the scaling law expected to hold for the effective exponents. The model considered by Shnidman is found unable to explain the nonuniversal critical behaviour.