The effect of solvent surface tension on surface freezing in n-alkane solutions

Surface freezing was investigated in solutions of the n-alkane docosane, as a function of concentration, using solvents of both higher and lower surface tension (γ). The solvents of higher γ enhance the thermodynamic stability and thus the temperature range of the surface crystalline phase (ΔT), while lower γ decreases ΔT. This directional dependence is consistent with the theoretical explanation of surface freezing in alkanes being driven by the entropy of ordering competing with the relatively low solid–vapor and solid–liquid interfacial tensions of the ordered CH3− surfaces, compared to the higher liquid–vapor surface tensions.