Evidence for dipole surface orientational order at critical interfaces

At the critical interface of dipolar systems theory predicts that the amplitude of the surface orientational order ${\alpha }_2\mathrm{}\left(z\right)\mathrm{}\sim m^{*4}{d}^2{v\left(z\right)/dz}^2,$ where $m^{*}$ is a reduced dipole moment and $v\left(z\right)\mathrm{}$ is the local composition at position z within the interface. We find quantitative agreement with these predictions for two different critical binary liquid mixtures composed of a highly polar and a nonpolar component.