Preparation of polybenzoxazole nanofibers by a downsizing process

Abstract

Poly(p-phenylene benzobisoxazole) (PBO) nanofibers were prepared from commercially available PBO fiber by a simple downsizing process for the first time. Partial alkaline hydrolysis of the oxazole ring brought ionic functional groups onto the fiber surface, enabling the disintegration of the PBO fiber into nanofibers with the help of an electrostatic repulsive force. The obtained nanofibers, whose average diameter was 24 nm, were characterized by SEM, FT-IR, ζ-potential analysis, XRD, and TGA. They dispersed homogeneously in water due to the surface charges. Filtration allowed a PBO nanofiber sheet to be easily prepared from the homogeneous dispersion in water.