Photocatalytic Fiber with Gradient Surface Structure Produced from a Polycarbosilane and Its Applications

Abstract

We developed a new in‐situ process for preparing functional ceramic fibers with a gradient surface layer by means of precursor methods using a polycarbosilane. After incorporation of selected low‐molecular‐mass additives into the precursor polymer from which the ceramic forms, thermal treatment of the resulting bodies leads to controlled phase separation (“bleed out”) of the additives. Subsequent calcination stabilizes the compositionally changed surface region, generating a functional surface layer. Using this technology, we developed a strong photocatalytic fiber (TiO2‐covered SiO2 fiber), which effectively decomposed many types of organic chemicals and bacteria into CO2and water by irradiation with UV light. Furthermore, we performed some field tests using a circulation purifier with a module composed of the cone‐shaped felt material of our new fiber.