A smart thermoregulatory nanocomposite membrane with improved thermal properties: simultaneous use of graphene family and micro-encapsulated phase change material

Abstract

This study is an attempt to improve the thermal properties of polyacrylamide (PAAm) membrane using graphene oxide (GO) and reduced graphene oxide (rGO) as a static modifier and phase change material micro-capsules (mPCMs) as a dynamic modifier at the same time. Fourier transform infra-red spectroscopy, X-ray diffraction and transmission electron microscopy were applied to prove GO and rGO synthesis. Dynamic heat transfer simulation apparatus and the transient heat transfer model were used to study the transient temperature behavior of the samples. Scanning electron microscopy and differential scanning calorimetry were also used to study the morphological properties and thermal behavior of hydrogels containing mPCMs. The addition of GO and rGO to the PAAm matrix increased thermal conductivity 2 and 2.5 times more than pure PAAm. Moreover, studying the transient temperature rates and mathematical simulations for PAAm containing GO and rGO revealed that rGO had better performance than GO in improving thermal properties. These hybrid nanocomposites increased the thermal conductivity of the fabrics thanks to the presence of rGO nanosheets and heat absorption capacity by mPCMs. It was also found that the presence of rGO improved the heat absorption performance of mPCMs to some extent. This long-awaited improvement in the thermal properties of the hydrogel membrane can be potentially harnessed to enhance user comfort in protective clothing.