Cation‐ π Reinforced Terpolymer with Tunable Energy Dissipation, Self‐Healing, and High‐Impact Resilience

Abstract Developing impact‐resistant materials with superior energy dissipation and mechanical adaptability is crucial for protective applications. Herein, a multifunctional terpolymer, poly(butyl acrylate‐ random ‐styrene‐ random ‐octyl vinyl imidazolium bromide) [poly(BA‐ r ‐St‐ r ‐[octVIm]Br)] is reported, engineered to achieve high impact‐resilience behavior through cation‐ π interactions between styrene (St) and octyl imidazolium bromide ([octVIm]Br) units. This molecular design enhances mechanical robustness and enables strain‐dependent viscoelastic behavior, transitioning from a rigid state at low strain rate to a soft, dissipative state at high strain. Rheological studies confirm a high storage modulus (G′) and a tunable damping factor (tan δ = 1.06–1.35), ensuring efficient shock absorption and energy dissipation. Thermal analysis reveals excellent thermal stability, with degradation onset at ≈280 °C, making PE40 suitable for high‐temperature applications. Additionally, self‐healing properties enable mechanical integrity recovery post‐damage, while strong adhesive interactions enhance interfacial bonding, broadening its application scope. The cation‐π interaction of PE40 enables significant toughness, durability, and adaptability, making it a promising candidate for protective coatings, structural reinforcements, and energy‐damping applications. This strategy provides a pathway for designing next‐generation impact‐resistant and self‐repairing polymeric materials with enhanced performance.