Bacterial-Cellulose-Reinforced Graphite Nanoplate Films for Electromagnetic Interference Shielding, Heat Conduction, and Joule Heating

With the flourishing development of wireless communication,thereis an urgent need for flexible and robust materials with excellentthermal conductivity (TC) and electromagnetic interference (EMI) shieldingperformance through simple and green preparation. In this work, weefficiently prepared bacterial-cellulose-reinforced graphite nanoplate(BC-GNP) composite films by the vacuum filtration of BC/GNP mixturedispersions. Compared with the pure GNP film with a loose and disorderedstructure, the BC-GNP composite showed a highly aligned and compact"brick-and-mortar" structure. Benefiting from the uniquestructure, the resultant BC-GNP with 20 wt % BC (20%BC) exhibiteda high tensile strength of 47.3 +/- 1.8 MPa and an electrical conductivityof 76.9 +/- 3.3 S/cm. As expected, the 20%BC showed excellent EMIshielding effectiveness (EMI SE) of 36.4 dB and a specific EMI SE(SSE/t) value of 8860 +/- 400 dB center dot cm(2)/g with a thicknessof 38 +/- 1 mu m. The in-plane TC and anisotropy index couldreach up to 80.2 +/- 6.4 W/mK and 73 +/- 3, respectively. The20%BC also exhibited a satisfactory Joule heating performance of 139 degrees C at a voltage of 6 V. More importantly, the 20%BC possesseda biodegradable property, which would completely degrade after 5 days.Thus, this work provides a strategy to facilely prepare biodegradable,high-performance, and multifunctional materials for wearable devices.