Solid–Liquid Interfacial Energy of Solid Neopentylglycol Solution in Equilibrium with Neopentylglycol–Aminomethylpropanediol Eutectic Liquid

The grain boundary groove shapes for solid neopentylglycol solution (NPG-40 mol pct AMPD) in equilibrium with the neopentylglycol (NPG)–aminomethylpropanediol (AMPD) eutectic liquid (NPG-42.2 mol pct AMPD) have been directly observed using a horizontal linear temperature gradient apparatus. From the observed grain boundary groove shapes, the Gibbs–Thomson coefficient (Г) and solid–liquid interfacial energy (σ _SL) of solid NPG solution have been determined to be (7.4 ± 0.7) × 10⁻⁸ K m and (6.4 ± 1.0) × 10⁻³ J m⁻², respectively. The grain boundary energy of solid NPG solution has been determined to be (12.5 ± 1.0) × 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 has also been determined to be 0.48.