Flexible octadecylamine-based shape stabilized composite phase change materials with high-enthalpy and enhanced thermal conductivity: A study combining experiment and molecular simulation

Due to inherent rigidity, liquid phase leakage, and low thermal conductivity, the application of organic phase change materials (PCMs) in thermal management technology faces challenges. In order to solve these problems, the polydimethylsiloxane/expandable graphite/polydopamine-modified graphene oxide (PDMS/EG/GO@PDA) foam with double thermal conduction framework was prepared by sugar template assisted method. Then the form-stable composite phase change material (CPCM) with flexibility was prepared by impregnating molten octadecylamine (ODA) with PDMS/EG/GO@PDA foam under vacuum. The results show that the prepared CPCM has good flexibility and can maintain good shape stability at 70 degrees C. The phase change enthalpy of CPCM reaches 103.1 J/g. Based on EG and GO@PDA, the thermal conductivity of CPCM is improved by up to 193 %. Meanwhile, the mechanism of GO@PDA affecting the interface properties and thermal conductivity of CPCM was revealed by molecular simulation. The simulation results show that after the introduction of GO@PDA into CPCM, the interface interaction and phonon vibration matching between filler and matrix are enhanced due to hydrogen bonding, which contribute to reducing the interface thermal resistance and enhancing the heat transfer at the interface. This study is expected to provide guidance for the preparation of thermal conductivity enhancement of CPCM.