Conclusions
PVP/Eu-PEG composite fibers were successfully electrospun as new phase-change luminescent materials. The morphology and thermal properties of the composite fibers changed dramatically by adjusting the molecular weight of PEG. The average fiber diameter generally increased with increasing PEG molecular weight in the composite fibers. It was found that the molecular weight of PEG plays an important role in the latent heat of the composite fibers, but has less effect on their phase-change temperature. The light-emitting and thermal characterizations show that this PVP/Eu-PEG material has both good phase-change properties and excellent luminescent proper- ties; therefore, the electrospun PVP/Eu-PEG composite fibers are promising for serving as luminescent materials in thermal energy storage.