Super-Foldable Glass-Like Plastic

Fatigue-free foldability is required for next-generation flexible electronics. For the essential protective films, ultrathin glass is susceptible to brittle fractures, whereas plastic films have inadequate hardness and tend to crease under dynamic loading conditions. We report a glass-like plastic featuring a nano-hybrid interpenetrating network comprising a plastic nanofibrous scaffold interpenetrated by an organic-inorganic silsesquioxane@nanosilica composite, which effectively inhibits fatigue relaxation. This hybrid material possesses glass-like transparency and hardness yet exhibits plastic-like elongation and impact resistance, and rubber-like resilience. When manufactured as thin films (5-30 µm), they can withstand extreme folding cycles (500,000 cycles at a radius of curvature of 0.5 mm) without macroscopic creasing/cracking or microscopic structure/morphology changes. The superior dynamic foldability of these glass-like plastics makes them promising for future device applications.