Facile fabrication of multifunctional aramid fibers for excellent UV resistance in extreme environments

Aramid fibers (AFs) are widely applied as structural material, cordage, and versatile protection in many harsh environments, including space and deep sea. However, intense ultraviolet (UV)/ irradiation, high/low temperatures, and/or chemical solvent with strong acid/alkali/corrosion feature seriously affect their mechanical properties, thus severely shorten the life cycle of AF-based products. Inspiration by the principle of multiple refractions and partly reflections, an innovative strategy by depositing of laminated Al2O3/TiO2 composite onto the surface of poly(m-phenylene isophthalamide) (PMIA) via atomic layer deposition (ALD) technique was presented. The tenacity of ALD-coated PMIA only decreases by ∼ 8 %, and the yellowness index (YI) only increasing to 129.24 %, far lower than 321.63 % of pristine PMIA fabric under the combination of intense UV irradiation (4260 W/m2) and high temperature (200 °C + ) for 6 h, which equals to continuous strong sunlight exposure for approximately 7.5 years. Meanwhile, UPF value increased to 126.4, which is double that of the pristine PMIA fabric, exhibiting an impressive UV-resistance property. Furthermore, the ALD-coated PMIAs also shows a significant enhancement in both chemical and thermal stabilities. In all, this work not only forge a new route for the functionalization of fibrous materials, but also exhibits great promise for next generation advanced composite material and cutting-edge equipment in harsh environment.