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.

Development of Highly pH-Sensitive Hybrid Membranes by Simultaneous Electrospinning of Amphiphilic Nanofibers Reinforced with Graphene Oxide

“…The graphs at the bottom of Figure 3 show the electrospinning process created fibers with a bimodal diameter distribution. This distribution of fiber diameter is highly favoured in the PC sector [15], for filtration [16,30], and for creating mats/meshes for tissue engineering [26] and cellular infiltration [31] applications. As the fiber diameter decreases, so does the pore diameter [30].…”

“…This distribution of fiber diameter is highly favoured in the PC sector [15], for filtration [16,30], and for creating mats/meshes for tissue engineering [26] and cellular infiltration [31] applications. As the fiber diameter decreases, so does the pore diameter [30]. This is particularly useful in some cases, such as PCs, where improved windproof properties of membranes are highly desired, or in wound dressing, where warding off aerosol particles and viruses is important.…”

Development of thermo‐regulating fabrics with enhanced heat dissipation via graphene‐modified n‐octadecane microcapsules

“…[42] Although there are many studies on thermal conductivity enhancement of PCM microcapsules, there are limited number of studies investigating the thermal conductivity properties of PCM-microcapsule-coated fabrics. [48,56,58,59] Shemsadi et al developed a polyacrylamide (PAAm) membrane by coating PCM microcapsules (mPCMs) with graphene oxide (GO) and reduced graphene oxide (rGO) on polypropylene (PP) nonwovens with a micrometer adjustable film applicator. Thermal conductivity of the PAAm hydrogel-coated membranes (0.0024 W/m.K) was enhanced three times (0.0063 W/m.…”

“…High thermal conductivity (~3000 W/m.K) is one of the most important properties of graphene. [ 56 ] Graphene can be included in the shell structure as an additive during synthesis. Su et al produced paraffin microcapsules with graphene/melamine formaldehyde shell (MicroPCMs).…”

“…Thermal conductivity of the PAAm hydrogel‐coated membranes (0.0024 W/m.K) was enhanced three times (0.0063 W/m.K) with the addition of 0.5 wt% rGO, and two times (0.0052 W/m.K) with the addition of 0.5 wt% GO nanosheets. [ 56 ] Ruiz‐Calleja et al investigated the thermal behavior of mPCM‐coated cellulosic fabrics containing graphene. The coating paste was prepared with binder having mPCM and graphene (25% of mPCM) and, then, coated on cellulosic fabric with an adjustable scraper and metal frame set at 1 mm.…”