Molecular interactions study and thermophysical properties of glycerol-calcium chloride DESs: Insights from micro-nanoscale interfacial dynamics

Abstract

Investigating the relationship between molecular interactions and thermophysical properties offers valuable insights into the development of advanced heat transfer fluids. In this work, glycerol-calcium chloride-based deep eutectic solvents (DES) were systematically examined through quantum chemical calculations and experimental methods to reveal their unique molecular mechanisms and thermal performance. Strong hydrogen bonding and coordination interactions were identified as critical factors enhancing the stability of the DES system, at the B3LYP-D3/6-31G(d, p) theoretical level, the calculated binding energy of DES reaches −223.94 kJ/mol, significantly lower than that of pure glycerol (−61.62 kJ/mol), indicating stronger and more stable interactions. Experimentally, the DES exhibited exceptional thermal stability, retaining structural integrity below 200 °C, while its boiling point increased by 4–5 °C and freezing point decreased by 4–6 °C compared to glycerol. Additionally, at an 8:1 glycerol-calcium chloride molar ratio, the specific heat capacity was approximately 1.5 % higher at 80 °C, demonstrating superior thermal storage capacity. These findings highlight the potential of DES as environmentally friendly and high-performance alternatives for industrial heat transfer and energy storage applications.