Decorating aramid fibers with chemically-bonded amorphous TiO2 for improving UV resistance in the simulated extreme environment

Abstract

Aramid fiber holds a great potential application in harsh environments like defense and aerospace due to outstanding integrated properties, but it still falls short in poor UV resistance and surface inertness. It is an intriguing but challenging task to obtain high anti-UV efficiency for aramid fiber without compromising the mechanical characteristics. Herein, a uniform and thickness-controlled amorphous TiO2 coating is chemically-bonded onto aramid fiber surfaces via a modified atomic layer deposition (mALD) strategy. Although mALD TiO2 has an amorphous structure, its special chemical bonding state similar to LBL enables it to absorb UV light to a certain extent, but at the same time endows it with low photocatalytic activity. In contrast to bare aramid fiber with poor UV resistance and greatly suppressed mechanical performance, the modified aramid fibers with 1000 ALD cycles possesses well-preserved mechanical strength and flexibility. Moreover, they exhibit 54.08% retention of initial tenacity even exposure to UV irradiation with intensity of 4260 W/m2 at high temperature (>200 °C) for 360 min (equals to continuous exposure to strong sunlight irradiation for about 7.5 years), simultaneously retain the excellent laundering durability and lustrousness, demonstrating a significant enhancement in anti-UV efficiency. Such highly anti-UV fibers fabricated by a facile mALD strategy provide a new perspective on designing multifunctional fibers and devices for future innovative applications.