Enhancement of thermal and mechanical properties of microencapsulated phase change materials with graphene oxide

The low thermal conductivity of microencapsulated phase change materials (MEPCMs) limits the latent heat charging and discharging rates for various applications. To overcome this limitation, we prepared MEPCM by co-surfactants of polyvinyl alcohol and high thermal conductivity graphene oxide (GO) through an emulsion polymerization process. Fourier transformation infrared spectroscopy and Raman spectra results verified that GO was successfully added to the MEPCMs' hybrid polymer shell. The core material content of MEPCM and GO/MEPCM was within the range of 78.4 %−91.8 % according to differential scanning calorimetry testing results. According to the comparison of fabricated microcapsule samples, the dosage of 0–0.5 w.t.% GO can reduce the loss of shell monomers and overcome the supercooling and leakage problem of MEPCM. Thermogravimetric results exhibited that the thermal stability of MEPCM samples increased by 66 °C after encapsulation, and this value further increased by 7–21 °C with the addition of 0.1–0.5 w.t.% GO. The thermal conductivity of MEPCM samples increased from 0.32 W/m∙K to 1.04 W/m∙K with a dosage of 0.5 w.t.% GO. Meanwhile, Young's modulus and the hardness of GO/MEPCM samples with 0.5 w.t.% GO increased by 0.2 GPa and 0.1 GPa, respectively.