Fabrication of a Dynamic Energy Dissipation Hierarchical Noncovalent Network for Folding Resistances

Abstract

Abstract The emerging stress‐induced buckling failure in the ultra‐thin flexible displays market demands innovative solutions for enhanced reliability. This study develops a hierarchical dynamic cross‐linking network via hydrogen bonding/metal coordination/cation–π synergism in colorless poly(amide‐imide) (CPAI) films, enabling cross‐scale stress equilibrium. Multiscale characterization coupled with MD simulations unravel the tri‐modal dissipation mechanism in calcium‐modified CPAI (CPAI‐Ca): hydrogen bonds serve as primary energy dissipation units, while the dynamically reversible metal coordination bonds (with 1.98–6.59 Å extensible/compressible slip space) and cation–π interaction networks (forming a broad stress buffer zone of 6.59–9.82 Å) collaboratively establish multiscale energy dissipation pathways through molecular chain slip. The optimized CPAI‐Ca withstands 200 000 folds at 0.5 mm radius (10x improvement over conventional CPAI) while suppressing buckling deformation by 92.8%. A real‐time monitoring system reveals minimal resistance variation (Δ R / R 0 = 7.35%) and uniform stress distribution after 200 000 commercial‐scale folding cycles (r = 1 mm). The material concurrently achieves outstanding thermal stability ( T g = 398.77 °C), high optical transparency ( T 550 = 89.38%), and remarkable modulus ( E = 5.47 GPa). This multifunctional integration establishes CPAI‐Ca as an innovative material solution for ultrathin flexible display applications.