Structure and phase transition behaviors of water in carbon nanotube under the electric field and high pressure

Abstract

The structure and phase transition behaviors of the confined water in a (3, 15) carbon nanotube (CNT) (diameter = 1.26 nm) under the different axial electric fields and the ultra-high pressure P = 1 and 10 GPa were studied by perform molecular dynamics simulations. Depending on the pressure and the strength of the applied fields, the confined water presents four ice structures. Under zero of fields, the hollow 〈7, 0〉 ice nanotube (ice-NT) is the unique ice phase to the water confined in (3, 15) CNT. Applying an electric field triggers a helical water chain forming on the axis of the ice-NT. The structural order of water competes with its degree of polarization in its first–order solid-liquid phase transition. Therefore, high-intensity fields are not conductive to the formation of the ice. However, continuous phase transition tends to occur in the case of ultra-high pressure.