Cellulose-derived flexible carbonized paper for high-performance electromagnetic interference shielding

Abstract

In this study, we describe the fabrication of flexible carbonized paper (f-CP) from toilet paper samples using a sandwich-type installation technique in a thermal chemical vapor deposition system. During the reaction, the substrate was heated up to 1000 °C at a rate of ~20 °C/min and naturally cooled down to room temperature in an Ar gas environment without temperature holding. The f-CP sample thus obtained contained continuous carbon fibers similar to the native toilet paper sample while carbonized paper (CP) fabricated using the conventional installation technique contained discontinuous carbon fibers. Compared to CP, f-CP exhibited higher electrical conductivity, mechanical flexibility, and shielding effectiveness (SE) against electromagnetic radiation. Even after bending the f-CP sample several hundred times, its SE decreased only slightly. Multi-layered f-CP (mf-CP; 3 mm thickness and 0.053 g/cm3 density) fabricated by stacking f-CP samples showed a remarkably high SE of 58 dB in the operating frequency range of 8.2–12.4 GHz. Therefore, f-CP and mf-CP, which exhibit excellent electromagnetic shielding characteristics, may potentially be used in electronic devices.