High Thermal Conductivity Porous Organic Polymers with Low Permittivity via Desolvation‐Induced Self‐Assembly

Abstract Miniaturization of microelectronic devices demand organic dielectric polymers with ultralow permittivity ( k < 2.0) and high thermal conductivity (λ > 1.0 W·m −1 ·K −1 ) to mitigate signal delay and thermal accumulation. However, organic polymers inherently face a trade‐off: porosity reduces k but sacrifices λ due to disordered pores and interchain hopping barriers. Here, a desolvation‐induced self‐assembly strategy is proposed, fabricating all organic porous polyacrylonitrile (P‐PAN) films. By incorporating polyethylene glycol (PEG) as a porogen and plasticizer, followed by water exchange and freeze drying, the P‐PAN film features uniform microscale holes, which reduce dipole density and electronic polarization, resulting in k to 1.44 (73.1% reduction from PAN). Simultaneously, PEG‐induce hydrogen bonds enable PAN chains mobility, promoting the reorganization of amorphous chains into crystalline domains during desolvation. This ordered framework facilitates efficient phonon transport via crystalline domains, elevating λ to 1.39 W m −1 K −1 , nearly tenfold improvement over PAN (0.13 W m −1 K −1 ). Notably, P‐PAN synergizes k < 2.0 and λ > 1.0 W·m −1 ·K −1 without fillers, surpassing state‐of‐the‐art organic polymers. As a proof of concept, P‐PAN as a thermal interface material (TIM) reduces chip temperature by 5.7 °C, decoupling the k ‐λ trade‐offs in organic polymers and demonstrating its potential for flexible electronics.