Critical Behavior near a Vanishing Miscibility Gap

Abstract

We report measurements of the osmotic susceptibility and correlation length for the pseudobinary mixture of guaiacol ($o$-methoxy phenol) plus glycerol-water as a function of temperature and water content $x[x\equiv \mathrm{weight}\mathrm{of}\mathrm{water}/(\mathrm{weight}\mathrm{of}\mathrm{water}\mathrm{plus}\mathrm{weight}\mathrm{of}\mathrm{glycerol}\left)\right]$. This system exhibits a limited two-phase region which vanishes for $x<\mathrm{}{x}_0\simeq 0.0137$. We observed a smooth transition from nearly Ising-type behavior for $x\gtrsim 4x_0$ through a non-power-law regime to doubled exponents for $x\simeq x_0$ and saturating divergences with doubled exponents for $x<\mathrm{}{x}_0$.