Epitaxial Growth of n-Tridecane Low-Pressure Phase Filmy Crystal on Its High-Pressure Phase

Abstract

We measured the p–T diagrams of four odd normal alkanes including n-tridecane, which have two equilibrium lines on which the orthorhombic (SII) and hexagonal (SI) solids coexist, and the SI and liquid coexist. The equilibrium lines of n-tridecane nearly overlap above 40 °C and separate from each other with temperatures decreasing less than 40 °C. We also show that the metastable area of SII of n-tridecane widely spreads below the SII–SI coexistence line. We focused on the reason why the metastable region of the SII crystal spreads, based on the transformational relationship between SI and SII and the unisotropies among the SI and SII singular interfaces. The SII crystal first appears from the liquid above 40 °C just after compression, due to the narrow stable region of the liquid–SI crystal system. When the temperature and pressure of the liquid–SII crystal system vary compared with those of the wide stable region of the liquid–SI crystal system, the filmy SI crystal can grow on its SII crystal in the liquid. Therefore, the arrangement and the wide area cause the epitaxial growth of SI filmy crystal on SII crystal.