Layered nanofibrillated cellulose hybrid films as flexible lateral heat spreaders: The effect of graphene defect

The effect of graphene defects on the performance of polymer-based material was investigated to obtain thermal conductive and strong materials for various commercial portable electronics. The flexible lateral heat hybrid films based on graphene sheets (GSs) and nanofibrillated cellulose (NFC) were fabricated via a vacuum-assisted self-assembly technique. The hybrid film with low-defect density GSs exhibited high thermal conductivity (TC) of 6.75 W m(-1) K-1 at 10 wt % GS loading. Compared with pure NFC film, the hybrid film showed excellent enhancement of 501.6%, which was 1.5x times higher than those with high-defect density GSs. The relationship between defect density of GSs and TC of hybrid films was consistent with the published simulation results. Meanwhile, the hybrid film with low-defect density GSs also exhibited higher toughness, tensile strength and Young's modulus than those with high-defect density GSs. NFC/GS hybrid films With high TC and mechanical properties can be used as a potential candidate for flexible lateral heat spreaders. (C) 2017 Published by Elsevier Ltd.