Synthesis of solid and spirally cracked TiO2 fibers by a liquid mix process

Titania fibers were synthesized by a liquid mix process, starting by complexing titanium isopropoxide with a chelating agent solution to form a precursor resin for further fiber drawing. The as-drawn continuous precursor fibers underwent a weight change of 80% and a volume change of 75% after heat treatment at 800 degreesC in nitrogen followed by an additional treatment at 600 degreesC in air. The fibers consisted mainly of rutile with 5-10% anatase. Further treatment at 700 degreesC transformed the anatase completely into rutile. Fibers with finished diameter less than about 15 mum were solid with smooth surfaces. Fibers with finished diameter greater than about 15 mum were hollow and spirally cracked in a uniform manner. Fibers treated at 600 degreesC showed no visible grains. Additional annealing at 800 degreesC grew grains to an average size of 0.3-0.4 mum. The fibers appeared solid and dense.