Thermodynamic anomalies and structural fluctuations in aqueous solutions of tertiary butyl alcohol

In this work, we discuss the connection between the anomalies of the thermodynamic properties, experimentally observed in tertiary butyl alcohol (TBA) and water solutions, and the molecular clustering in these solutions, as revealed by molecular dynamics (MD) simulations. These anomalies are observed in relatively dilute solutions of about 0.03 to 0.08 mole fraction of TBA and become more pronounced at low temperatures. MD simulations show that these solutions exhibit shortranged (order of 1 nm), shortlived (tens of picoseconds) "micelle-like" structural fluctuations in the same concentration range. We attribute the anomalies in the thermodynamic properties of aqueous TBA solutions to these structural fluctuations on the molecular scale.