Investigating the effect of crystallizability and glass transition temperature of supporting materials for preparing high enthalpy electrospun poly(lactic acid)/poly(ethylene glycol) phase change fibers

Form-stable phase change fibers (PCFs) that are composed of stable supporting material (as polymer matrix) and phase change material (PCM, as working ingredient) have become novel smart materials, being widely applied in energy storage, thermal regulation and the biomedical field. However, the inherent limitation of PCFs is the restriction of the supporting material on the crystallization of the PCM, which results in low phase change enthalpy (AH). Here, six different types of PCF comprised of poly(lactic acid) (PLA, as supporting material) and poly(ethylene glycol) (PEG, as PCM) have been fabricated. Their morphology, phase change performance and structural transitions during phase change have been extensively studied. We reveal that the crystallizability and glass transition temperature of PLA have a dominating influence on AH. In the optimum system, PLA/PEG PCFs can achieve up to 104 J/g AH which is close to the theoretical value of pristine PEG. This high-performance PCF also exhibits only 2.5% AH loss after 100 thermal cycles and good ability in thermal energy storage and thermal regulation. This work provides a promising form-stable PCF and introduces a new strategy towards developing high AH PCFs by selecting suitable supporting materials.