A theoretical study on the size and morphology dependency of integral melting enthalpy and entropy of nanomaterials

Due to the fact that the melting process of nanomaterials is carried out with the continuous change of melting temperature, previous equations of differential melting enthalpy and entropy are unable to reflect their thermodynamic behaviors of actual melting process. On the basis of our previous work, theoretical calculations were conducted on the size and morphology dependent integral melting enthalpy and entropy of nano-sized Au, Ag and Sn and reasonable agreements with experimental results were observed. In addition, the integral melting enthalpy and entropy were also compared with the corresponding differential quantities. The differences between integral and differential melting enthalpy are mainly determined by the surface area and the interfacial tension, and the melting entropy by the surface area and the temperature coefficient of interfacial tension. The findings are able to deepen our understanding of the size and morphology dependent melting thermodynamics of nanomaterials and to further develop the thermodynamic theory of phase transitions of nanomaterials.