Low dielectric and high thermal conductivity polyimide nanocomposites with fully closed-loop recycling and highly consistent healing

Abstract

Multifunctional Polyimide (PI) with low dielectric and high thermal conductivity are widely utilized in high-signal-frequency and high-integration electronic devices, yet they are vulnerable to damage within complex operating environments. The development of such high-performance multifunctional composites with recyclable and repairable capability has represented significant challenges. Herein, novelty supramolecular PI nanocomposites comprising Schiff base bonds and hydron bonding interactions via amino-terminated polyimide, functionalized boron nitride nanosheets and aldehyde-containing crosslinking agents maintain the inherent high thermal stability and tensile strength of conventional PI and demonstrate fully closed-loop pH-adjusted liquid-level and high-purity powder-level recyclability, as well as superior healing ability after various mechanical or electrical damage. The resultant PI nanocomposite exhibits notable comprehensive performance, with high recycled in-plane and through-plane thermal conductivity of 8.69 and 5.44 W m⁻¹ K⁻¹, low recycled dielectric constant of 2.98 at 1 MHz and excellent healed dielectric breakdown strength of 378.9 kV mm⁻¹, as well as high recovery rates. Furthermore, the repairable triboelectric nanogenerator based on the PI nanocomposite exhibits excellent shape tailorability and nearly-consistent output electrical performance. The concepts presented in this paper offer practical solutions for sustainable high-performance electronic materials and shed light on the integrated structural design of green nanocomposites.