LAUSR

Abstract The solid-liquid phase behavior of three saturated aliphatic symmetrical sulfones (n-SO2-n) were assessed for potential use as Phase Change Materials (PCM) using TGA, DSC and XRD. The compounds were synthesized in high yield and purity via the simple solvent-free oxidation reaction of the fatty sulfides. The sulfones demonstrated properties suitable for medium temperature thermal energy storage applications. TGA measurements confirmed that the sulfones commences weight loss with onset temperatures up to 283 °C. The crystal structure and the thermal transition parameters of the sulfones were not significantly affected by cooling rate. 18-SO2-18 and 12-SO2-12 crystallized in the thermodynamically stable β-form and 10-SO2-10 crystallized in the γ-form, and all adopted single-molecular layer stacking configurations along the plane normal. DSC indicated that these compounds can rapidly store and release large amounts of thermal energy (>200 J/g) as latent heat between 89-109 °C with minimal supercooling. The sulfones presented higher melting temperatures compared to analogous monofunctional lipid-based counterparts such as fatty acids, fatty alcohols, ethers, monoesters, diesters, monoamides and alkanes attributed to the added strong sulfonyl-sulfonyl attraction between the highly polar sulfonyl groups. Importantly, this work shows that linear saturated lipid-based sulfones can extend the available range of the current available organic, lipid-based PCMs.