Thermally Conductive Boron Nitride Nanosheet Composite Paper as a Flexible Printed Circuit Board

The development of portable and wearable electronic devices has substantially increased the demand for printed circuit boards with high thermal conductivity, optimal mechanical flexibility, electrical insulativity, and minimal high-frequency transmission loss. Herein, we demonstrate the fabrication of a thermally conductive, flexible composite paper, for electronic and microwave devices, based on hexagonal boron nitride nanosheets, poly(vinyl alcohol) (PVA), and fiberglass mesh (FGM). The prepared composite paper exhibits in-plane thermal conductivity of 22.51 W/(m·K), and the FGM induced high mechanical strength of 27.92 MPa. The transmission loss, of the grounded coplanar waveguide lines, was 0.10 dB/mm at 7.0 GHz, and shows negligible variation while bending, indicating the high flexibility of the circuit board. These results demonstrate potential application of BN-based composite paper in flexible electronic devices.