Charge induced hydrophobic/hydrophilic metallic surfaces

Understanding the interaction of water-metal systems in an atomic level is of fundamental importance in many areas, such as catalysis and materials science. We here present a detailed first-principles molecular dynamics study of bulk water molecules confined within Pd(111) surfaces. We show that there is a charge transfer between the substrate and the water inducing an asymmetry in the order of water molecules at Pd surfaces. Our results show that the hydrophobic/hydrophilic character of a metallic surface depend on its charge, which can be controlled by an applied voltage. We also propose a methodology to obtain the dipole moment of each water molecule and show how they are affected by the substrate induced polarization effects.