Spinodal decomposition in a binary liquid mixture near the critical point

Abstract

Light scattering was used to study the nonlinear behavior of spinodal decomposition in a binary mixture of 2−6 lutidine−water near its lower critical point. We have photometrically analyzed the time evolution of the differential scattering cross section following a quench into the thermodynamically unstable spinodal region. Our results are in very good agreement with a mean field theory proposed by Langer. Using this theory we have determined the temperature dependence of the fourth concentration derivative of the free energy ∂4f/∂c4. The results are consistent with scaling if the nonclassical critical exponents are used.