New Critical Anomaly Induced in a Binary Liquid Mixture by a Selectively Adsorbing Wall

The upper demixing critical point in carbon disulfide + nitromethane bounded by a crown glass surface which is expected to preferentially adsorb nitromethane has been studied. The σ-polarized reflectivity of the liquid/glass interface rises sharply with decreasing temperature above the bulk critical temperature. This effect cannot be explained as a purely bulk phenomenon, but agrees well with an approximate version of the critical wall-layer theory of de Gennes and Fisher.