Smart composite nanofiber mats with thermal management functionality

Nuray Kizildag

doi:10.1038/s41598-021-83799-5

Abstract

Nanofibers with thermal management ability are attracting great attention in both academia and industry due to the increasing interest in energy storage applications, thermal insulation, and thermal comfort. While electrospinning is basically a fiber formation technique, which uses electrostatic forces to draw ultrafine fibers from a wide variety of polymers, with the addition of phase change materials (PCMs) to the electrospinning solution it enables the production of shape stabilized phase change materials with thermal management functionality. In this study, polyacrylonitrile (PAN) nanofibers containing paraffinic PCMs were produced by electrospinning method and the composite nanofibers obtained were characterized in terms of their morphology, chemical structure, thermal properties, stability, thermal degradation behaviour and hydrophobicity. Besides, PCMs with different phase transition temperatures were added simultaneously into the nanofiber structure in order to investigate the tunability of the thermoregulation properties of the nanofibers. Uniform nanofibers with thermal management functionality were obtained. It could be possible to obtain composite nanofibers showing thermoregulation ability over a wider temperature range by simultaneous addition of PCMs with different melting points into the nanofiber structure. 50 wt% PCM could be added to PAN nanofiber structure wherein the resulting nanofiber exhibited 58.74 J g−1 of enthalpy storage during heating and 57.41 J g−1 of heat release during cooling. The composite nanofibers maintained their cylindrical fiber morphology, structure and composition after multiple heating–cooling cycles and retained their thermal management functionality. The contact angle measurements showed that the addition of PCMs imparted hydrophobicity to the nanofibers.

Highlights

Nanofibers with thermal management ability are attracting great attention in both academia and industry due to the increasing interest in energy storage applications, thermal insulation, and thermal comfort
This study provides substantial contribution to the literature by showing the development of chemically, morphologically and thermally stable composite PAN nanofibers with thermoregulation properties, pointing out the required process parameters for the production of uniform-structured PAN/phase change materials (PCMs) nanofibers, showing the possibility of finetuning the properties of these nanofibers by incorporating different types of PCMs simultaneously into the nanofiber structure and changing their ratios in order to obtain higher storage/release capability over a wider temperature range, and providing comprehensive discussion regarding morphology, chemical structure, thermal properties, stability, thermal degradation behaviour and hydrophobicity of the composite PAN nanofibers containing PCMs
Differential Scanning Calorimetry (DSC) thermal cycling test indicated that the composite nanofibers had good thermal reliability as the thermal properties of electrospun composite nanofibers were well retained after thermal cycling

Summary

Introduction

Nanofibers with thermal management ability are attracting great attention in both academia and industry due to the increasing interest in energy storage applications, thermal insulation, and thermal comfort. The composite nanofiber mats containing PCMs were analysed with regards to their thermal properties (melting temperature ( Tm), crystallization temperature ( Tc), enthalpy of melting (ΔHm), and enthalpy of crystallization (ΔHc) of the samples) via DSC and compared to the PCMs. DSC is an effective method for testing the functionality of PCM materials.

Results

Conclusion