Effect of the alkyl chain length on the non-ideality and the microstructure of alcohol binary mixtures.

Abstract In this study the microstructure of alcohol binary mixtures (toluene and cyclohexane) is investigated from molecular dynamics simulations. In case of cyclohexane mixtures, we show that the strong deviation from the ideality is the result of the formation of nanophases of alcohol molecules gatheblack in aggregates from hydrogen bonds leading to the spatial heterogeneity. Nanophases disappear as the alkyl chain size increases because the hydrophobic interactions counteracts the hydrogen bonds ones. The aggregates of short alcohol are found uncorrelated at the long range correlations which is related to an absence of the prepeak at low Q in the total structure factor. From toluene similar trends are observed with a lesser extend given the favorable π -OH interactions.