Development of an encapsulated phase change material via emulsion and coaxial electrospinning

Abstract

This article reports on the encapsulation of a phase change material (PCM) into a hydrophilic polymer, poly(vinyl alcohol) (PVOH), by means of electrospinning. Different strategies were carried out to improve the thermal buffering capacity and the stability of the developed structures when they were exposed to different relative humidity (RH) conditions. On the one hand, the thermal energy storage capacity of PVOH/PCM structures obtained through emulsion electrospinning was optimized by using different amounts of polyoxyethylene sorbitan monolaureate (Tween 20). Surfactant addition successfully increased the heat storage capacity of the developed structures, reaching an optimum performance at a concentration of 0.32% in weight with respect to the total emulsion weight. However, the hydrophilic nature of the developed structures made them extremely difficult to handle due to swelling with increasing RH. To avoid this issue an additional shell layer of poly(caprolactone) (PCL), was applied by coaxial electrospinning. In this case, the PVOH/PCM ratio (core) was optimized to reach the highest heat storage capacity per gram of sample and, then, a PCL solution was used as a shell material to hydrophobize the structures. The optimized coaxial electrospun structures were able to encapsulate about 82% of PCM. The use of both emulsion and coaxial electrospinning strategies are introduced here for the first time as advanced strategies to overcome application issues such as unintended migration and performance drop in the previously developed monophase materials.

Nanoengineered electrospun fibers and their biomedical applications: a review

“…Hence, conventional fibers are often nanoengineered to either produce various morphologies or modify fiber properties. This nanoengineering of fibers has led to novel properties and applications such as selfhealing [177], heat storage [178], and sensors [179]. In the following section, some biomedical applications of nanoengineered electrospun fibers are further introduced and discussed.…”

Preparation, properties and characterisation of microemulsion PCM slurry

“…The paraffin phase in microemulsion changed from solid to liquid between 26 and 41°C with a ΔH m of 72.25 J g −1 and T m of 33.2°C. Paraffin content in microemulsion was further calculated based on ΔH m , by assuming that the other components in the microemulsion did not affect the ΔH m of PCMs [32][33][34][35]. Accordingly, the content of paraffin in microemulsion was 43.8 wt %.…”

Development of core–sheath structured smart nanofibers by coaxial electrospinning for thermo-regulated textiles

“…30 Wilson et al fabricated PVOH/PCM nanobers, and the latent heat was just 48.6 J g À1 . 31 Apparently, the latent heat of all the above prepared nanobers are not very high, thus, there is great potential for development in the fabrication of core-sheath structured bers with higher latent heat.…”