Construction of a 3D interconnected boron nitride nanosheets in a PDMS matrix for high thermal conductivity and high deformability

With the electronic device advancing to miniaturization, higher integration and flexibility, flexible polymer composites with high thermal conductivity are desirable for efficient removal of accumulated heat to maintain normal operation of electronics. In this work, a polydimethylsiloxane/boron nitride nanosheets (PDMS/BNNS) foam scaffold was prepared by the sugar-templated method, and the corresponding PDMS/BNNS composites were manufactured with vacuum-assisted PDMS impregnation and curing. The PDMS/BNNS composites exhibit a three-dimensional (3D) BNNS interconnected network with curved BNNS pathways due to the intensive compression during hot-pressing curing, providing thermally conductive network and corresponding prestrains for deformable application. The PDMS/BNNS composites finally can achieve a high thermal conductivity of 7.55 W m−1 K−1 in the in-plane direction and 1.12 W m−1 K−1 in the through-plane direction with 25 vol% BNNS, which represent 153% and 78% increases over the composites prepared by randomly mixing method, respectively. In addition, the composite still maintains superior heat dissipation property under repeated stretching and bending conditions, which indicates a broad and bright application for thermal management in flexible electronic devices.