Improvement of thermal conductivity and latent heat of cellulose film using surfactant and surface-treated CNT with stearic acid

The formation of a thermal path greatly contributes to the improvement of the thermal management performance of the polymer composite material. In particular, 3D thermally conductive networks are effective in building fast conductive paths in polymer composites. We fabricated a stearic acid (SA) carbon nanotube (CNT)/cellulose nanofiber (CNF) film with a 3D network. The film consisted of a filler loading of 70 wt% and demonstrated a thermal conductivity that was higher than that of neat CNFs by 259%. Furthermore, an X-ray diffraction test showed that the crystallinity of the composite changed during the foam structure formation owing to freeze-casting. Our results indicate that composites prepared with surface-modified CNTs showed high thermal conductivity and heat latent. This study proposes a process to significantly improve the thermal conductivity of polymer composite films through a simple system.