3D printing, leakage-proof, and flexible phase change composites for thermal management application

Phase change composites (PCCs) have attracted much attention in the fields of thermal management due to their high latent heat. However, their risk of leakage and poor shape designability greatly limit their industrial applications. Therefore, there is an urgent need to develop leakage-proof and customizable PCCs to meet the emerging requirements of thermal management applications. Some scholars have proposed the concept of preparing PCCs by 3D printing technology, aiming to meet customized thermal management requirements of various electronic devices. Nevertheless, the phase change material leaking of PCCs under high temperature is still a tough problem to solve. In this study, expanded graphite (EG) is used as the carrier for paraffin wax (PW), which names as EP can tightly enveloping PW in its porous structure. Then, an innovative carbomer gel ink is prepared for 3D printing using EP and short carbon fiber (SCF) as thermal conductive fillers. Freeze-drying and polydimethylsiloxane (PDMS) infiltrating procedures are furtherly performed to ensure the flexibility of final PCCs samples. A maximum thermal conductivity of 2.89 W/(m·K) is obtained when the content of SCF/EP filler is 10 wt%. Importantly, the flexible PCCs prepared through this method effectively prevent the PW leaking during thermal management applications, thereby avoiding the consequent safety risks and enhancing the lifespan of electronic devices. This work opens up a promising pathway for the rapid fabrication of leakage-proof, customizable and flexible PCCs.