Vertical alignment of carbon fibers under magnetic field driving to enhance the thermal conductivity of silicone composites

Abstract Thermal interface materials are expected to have efficient heat conduction pathways to achieve excellent thermal conductivity under the premise of low filler filling. It is a facile strategy to build thermal pathways through filler orientation technology under external force. Herein, iron oxide nanoparticles (Fe 3 O 4 ) were immobilized onto the surface of carbon fiber (CF) to prepare magnetic CF by polydopamine technology, and the oriented CF/polydimethylsiloxane composites (OCF/PDMS) were prepared through the vertically oriented cure of magnetized CF under an external magnetic field. Importantly, the thermal conductivity of OCF/PDMS reached up to 1.51 W m −1 K −1 when filling 20 wt% of CF@Fe 3 O 4 , which is 1.16 times of carbon fiber/polydimethylsiloxane composites and 5.59 times of pure PDMS matrix. In addition, OCF/PDMS also exhibits excellent tensile strength, elastic modulus and elongation at break. This strategy provides a promising attempt for the construction of thermal interface materials with high thermal conductivity and excellent mechanical properties.