Coconut oil-cellulose beaded microfibers by coaxial electrospinning: An eco-model system to study thermoregulation of confined phase change materials

Abstract

Coconut oil was used to produce biomass microfibers with a coconut oil core and a cellulose shell by a co-axial electrospinning technique. This novel material was developed as a model system to determine the effect of confining a phase changing material within an axial micropore of a coaxial fiber. The morphology of these composite fibers was determined by scanning electron microscopy and transmission electron microscopy, which revealed a unique beaded necklace morphology with sub-micron scale pockets of confined coconut oil. Thermogravimetric analysis and differential scanning calorimetry were employed to study the thermal behavior of the composite fibers. A significant increase of the specific heat capacity (+ 98%) was observed when the coconut oil was confined within the micropore of the composite fiber compared to the bulk. There was also a notable increase (+ 41%) of the specific heat of melting for the micropore confined coconut oil. Thus, coconut oil isolated in the axial micropore core of these cellulose composite fibers showed excellent potential for temperature regulation in the range of 7 to 22 °C, which includes 21 °C, the temperature which most humans find comfortable. The results of the studied model system can be used to tailor the properties of phase change materials in confined micropores, in both electrospun fibers and other mesoscale structures.