A 3D Printable Thermally Conductive yet Electrically Insulating Polymer Nanocomposite based on Ag@SiO2 Nanowires

What do high density batteries and up-to-date electronic chips have in common?<br/>The problem of heat dissipation.<br/>With the emergence of fast charging technologies, high energy density batteries and new generation microprocessors, the heat generation in such systems while in operation becomes significantly more intense. If this heat is not efficiently dissipated,: a) the risk of thermal runaway in batteries increases and thus threatens the users safety, b) the performance, lifetime and reliability of electronic systems weaken. Improvement of batteries and electronic devices performances is therefore closely linked to the effectiveness of the thermal dissipation of such systems. Besides high thermal conductivity, very good electrical insulation of these structural materials is also expected to avoid issues such as short circuits or higher power consumption.<br/>The use of thermoplastic polymers seems relevant due their intrinsic electrical insulation behavior and simple processability. However, such materials generally present low thermal conductivity (&lt; 0.4 W.m^-1.K^-1). An appropriate strategy for improving thermal conductivity while simultaneously preserving electrical insulation of polymer-based materials is to incorporate thermally conductive yet electrically insulating fillers to the polymer matrix.<br/>In this presentation, we will show that the development of one-dimensional silver-silica core-shell nanowires (AgNW@SiO₂) is a relevant route to very efficient heat dissipative nanocomposites. We will present how the fine tuning of the silica nanolayer on silver nanowires is of utmost importance to reach optimized performances.<br/>By adjusting the rheology of the nanocomposite, i.e. limiting the content of the nanofillers to 3 vol%, a proof of concept was 3D printed by FDM (Fused Deposition Modelling). Thanks to the alignment of the 1D nanofillers during the FDM printing process, as observed under various printing patterns, the thermal conductivity of the PC nanocomposite reaches an unprecedented value of 3.48 ± 0.06 W m^-1 K^-1in the printing direction, i.e. a fifteen-fold increase over the thermal conductivity of neat PC.