Flexible phase change filament with ionic liquid core

ABSTRACT A flexible phase change filament with core‑sheath structure was successfully prepared by post‐filling of a polypropylene (PP) hollow fiber. The ionic liquid (IL) 1‐butyl‐4‐methylpyridinium hexafluorophosphate was chosen as core component, while copper decorated muscovite (Cu‐MVT) was synthesized via in situ reduction and used as the refining additive for the IL. Results from differential scanning calorimetry demonstrated that the encapsulation ratio of the flexible phase change filament reached 93% with a fusion latent heat of 52.7 J/g at 48.3 °C. Supercooling of the ionic liquid was suppressed effectively as shown by the crystallization in the cooling step due to the addition of Cu‐MVT. The flexible phase change material with core‑sheath structure also showed good thermal stability, durability, and mechanical property under the protection of the sheath polymer material. It is evident that the phase change filament possesses promising characteristics for thermal energy storage and thermoregulation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47830.