Curvature-dependent melting models and melting thermodynamics of nanotubes in theory and experiment

Abstract

Currently, the melting thermodynamic properties of nanotubes are still unclear. In this paper, the generalized relation of chemical potential of nano-condensed phases was first derived, and two types of curvature surfaces with different phase transition activities were found on nanotubes. On this basis, two melting models of nanotubes were proposed, the relations between the melting temperature, the melting thermodynamic properties, respectively, and the curvature (reciprocal of the radius) of nanotubes were derived. And the correctness of the theory was verified by the melting of selenium nanotube. The results showed that the initial melting temperature, melting enthalpy and melting entropy decrease with increasing the curvature, and present good linear relationships with curvature, respectively. This theory can provide theoretical guidance and new clues for the design, preparation, research and applications of nanomaterials with negative curvature surface.