Solid–liquid interfacial energy of neopentylglycol solid solution in equilibrium with neopentylglycol–(D) camphor eutectic liquid

Abstract

The grain boundary groove shapes for equilibrated solid neopentylglycol (NPG) solution (NPG–3 mol% D-camphor) in equilibrium with the NPG–DC eutectic liquid (NPG–36.1 mol% D-camphor) have been directly observed using a horizontal linear temperature gradient apparatus. From the observed grain boundary groove shapes, the Gibbs–Thomson coefficient ( Г), solid–liquid interfacial energy ( σ SL) of NPG solid solution have been determined to be (7.5±0.7)×10 −8 K m and (8.1±1.2)×10 −3 J m −2, respectively. The Gibbs–Thomson coefficient versus T m Ω 1/3, where Ω is the volume per atom was also plotted by linear regression for some organic transparent materials and the average value of coefficient ( τ) for nonmetallic materials was obtained to be 0.32 from graph of the Gibbs–Thomson coefficient versus T m Ω 1/3. The grain boundary energy of solid NPG solution phase has been determined to be (14.6±2.3)×10 −3 J m −2 from the observed grain boundary groove shapes. The ratio of thermal conductivity of equilibrated eutectic liquid to thermal conductivity of solid NPG solution was also measured to be 0.80.