Preferential Orientations and Anomalous Interfacial Tensions in Aqueous Solutions of Alcohols

J Phys Chem B. 2020 Sep 24;124(38):8388-8401. doi: 10.1021/acs.jpcb.0c05412. Epub 2020 Sep 15.

Abstract

Literature studies on interfacial tension versus temperature between normal alcohols and water show that it increases with temperature and exhibits a maximum value at a given temperature depending on the molecular weight of the alcohol. This very unusual behavior is supposedly accompanied by the formation of monolayers of alcohol molecules oriented preferentially at the interface, a structural issue not confirmed until now. We use molecular-based models for water and alcohols in combination with molecular dynamics simulations to provide physical insights, from a molecular perspective, into the structural and thermodynamic behavior at the liquid-liquid interfaces of aqueous solutions of alcohols.