Entropy-Capturing Polymerization for High-Performance, Ultra-transparent Polyimides with Simultaneous Multiple Monomer Recovery via Salt Intermediates

Abstract

Sustainable electronics demand high-performance materials that reconcile advanced mechanical durability with end-of-life circularity. Here, we report a high-entropy design strategy for transparent polyimides, synthesized from salts of alicyclic tetraacids and a multi-component aliphatic diamine with a low carbon footprint. By exploiting the high-enthalpy and directional nature of ionic/hydrogen hybrid bonding between the hydrogen dicarboxylate anion and the amino cation, we successfully constructed multi-component monomer salt crystals that capture high entropy during polymerization upon heating. The configurational entropy effectively suppresses detrimental crystallization of the resulting copolyimides with multiple units while preserving robust thermal and mechanical integrity. The copolymides exhibit near-perfect optical transparency (∼92% transmittance, cutoff < 300 nm) and limited opacification. Crucially, the high-entropy state enhances bond accessibility for hydrolytic reactions, enabling simultaneous closed-loop recycling of multiple monomers via salts stabilized based on high-enthalpy bonding. Our findings establish high-entropy engineering of polyimides as a powerful paradigm for sustainable plastics, transforming the traditional performance–recyclability trade-off into a tunable, entropy-driven design space.