Bacterial-Cellulose-Reinforced\nGraphite Nanoplate\nFilms for Electromagnetic Interference Shielding, Heat Conduction,\nand Joule Heating

Abstract

With the flourishing development of wireless communication,\nthere\nis an urgent need for flexible and robust materials with excellent\nthermal conductivity (TC) and electromagnetic interference (EMI) shielding\nperformance through simple and green preparation. In this work, we\nefficiently prepared bacterial-cellulose-reinforced graphite nanoplate\n(BC-GNP) composite films by the vacuum filtration of BC/GNP mixture\ndispersions. Compared with the pure GNP film with a loose and disordered\nstructure, the BC-GNP composite showed a highly aligned and compact\n“brick-and-mortar” structure. Benefiting from the unique\nstructure, the resultant BC-GNP with 20 wt % BC (20�) exhibited\na high tensile strength of 47.3 ± 1.8 MPa and an electrical conductivity\nof 76.9 ± 3.3 S/cm. As expected, the 20� showed excellent EMI\nshielding effectiveness (EMI SE) of 36.4 dB and a specific EMI SE\n(SSE/t) value of 8860 ± 400 dB·cm²/g with a thickness\nof 38 ± 1 μm. The in-plane TC and anisotropy index could\nreach up to 80.2 ± 6.4 W/mK and 73 ± 3, respectively. The\n20� also exhibited a satisfactory Joule heating performance of 139\n°C at a voltage of 6 V. More importantly, the 20� possessed\na biodegradable property, which would completely degrade after 5 days.\nThus, this work provides a strategy to facilely prepare biodegradable,\nhigh-performance, and multifunctional materials for wearable devices.