Unparalleled Armour for Aramid Fiber with Excellent UV Resistance in Extreme Environment

Aramid fibers are widely used in many cutting‐edge fields, including space, aviation, military, and electronics. However, their poor UV resistance and surface inertness seriously hinder their utilization, especially in harsh environments. Here, a dual‐layer ultrathin Al(2)O(3)–TiO(2) coating with a thickness of 70–180 nm is fabricated on aramid fibers by a modified atomic layer deposition (ALD) method. The tenacity of ALD‐coated aramid fibers decreases only by ≈0.85% after exposure to intense UV light (4260 W m(−2)) under high temperature (>200 ℃) for 90 min, which equals to continuous exposure to sunlight for about 17 500 days. The as‐prepared aramid fibers also show excellent laundering durability, thermal and chemical stabilities. This work presents a green and damage‐free approach to achieve the highly anti‐UV aramid fibers without sacrificing their outstanding performance, which is expected to guide material design for future innovations in functional fibers and devices.