Tailoring Polyimide Chain by Melamine-Cyanurate Supramolecule via a Molecular Welding Strategy Achieving Superior Thermal Conductivity

Polyimide (PI) films are widely used in printed circuit boards, electronic packaging, interlayer media, display panels, and other fields. Improving the thermal conductivity of PI film is of great significance to promote effective heat removal in microelectronic devices. Herein, melamine cyanurate (MC) with multiple hydrogen bonds was designed and introduced into water-soluble polyamide acid (Ws-PAA) solution via an in-situ co-precipitation method. The MC supramolecule forms a chemical bond at the end of the PI chain, while also confines the adjacent chains through hydrogen bonds and π - π conjugation, functioning as a tailor to improve the chain arrangement via this molecular welding strategy. The tailored PI/MC films exhibit anisotropic thermal conductivity (TC): the in-plane TC can reach 0.93 W/(mK) while the through-plane TC is 0.60 W/(mK). Micromorphology and structural characterizations confirm the formation of complete heat conduction pathways. The developed films also show potential application prospects functioning as heat dissipation media in microelectronic devices.