One-pot aqueous co-assembly of biomimetic structural composite paper for synergistic enhancement of thermal conductivity and dielectric properties in advanced electronics

The increasing thermal and electrical demands of next-generation transformers and precision electronics necessitate the development of insulating materials that simultaneously exhibit high thermal conductivity, superior dielectric properties, and long-term reliability. Traditional aramid-based papers, while offering outstanding thermal stability and insulation, suffer from intrinsically low through-plane thermal conductivity. In this work, we report a nacre-inspired composite paper consisting of aramid nanofibers, guar gum, and mica (ANFs/GG/Mica), fabricated via a one-pot aqueous co-assembly process amenable to continuous manufacturing. Multivalent hydrogen bonding between amide groups, hydroxyl segments, and silanol surfaces forms a robust organic–inorganic interface, significantly reducing both interfacial thermal resistance and charge-carrier mobility. The optimized composite exhibits a through-plane thermal conductivity of 2.87 W m −1 K −1 at 150 °C and a dielectric breakdown strength of 86.9 MV m −1 , corresponding to enhancements of 62% and 28%, respectively, compared with pristine ANF paper. Notably, the composite paper retains over 70% of its mechanical strength after 168 h of ultraviolet (UV) aging, demonstrating excellent environmental stability. This work presents a flexible assembly strategy that leverages layered alignment and dense interfacial bonding to achieve a well-balanced combination of heat conduction, electrical insulation, and reliability.