  Based on recent studies on hydrophobic interactions, it is devoted to
investigate the directional nature of hydrophobic interactions. It means that
the hydrophobic interactions are dependent on the relative orientations as the
solutes tend to be aggregated in water. In H1w process, they are attracted to
approach each other in the specific direction with lower energy barrier until
their surfaces become contact. In H2s process, to maximize the hydrogen
bondings of water, the solutes are aggregated in the specific direction to
minimize the ratio of surface area to volume of them. Additionally, with
decreasing the separation between them, the short-range interactions between
the solutes become stronger. In addition, these can be demonstrated by the
calculated potential of mean force (PMF) using molecular dynamics simulation.
From this work, the hydrophobic driven model is proposed to understand the
specificity and affinity of molecular recognition in water.
