Thermoplastic Liquid-Crystal Polyarylate Nanofiber with an Ultrahigh Aspect Ratio

Abstract

As a building block unit, the thermotropic liquidcrystal polyarylate (PAR) nanofibers are expected to offer a more diverse and efficient processing model compared to that of the lyotropic liquid-crystal polymer nanofibers through their thermoplastic process. However, there is currently a lack of literature documenting the preparation method of PAR nanofibers. In this study, we successfully fabricated representative thermotropic liquid-crystal polymer nanofibers, namely, PAR nanofibers, employing a wet ball-milling technique. By investigating the aggregated state structure, microscopic morphology, and surface energy of PAR under different treatment conditions, we elucidated the underlying mechanisms governing the generation and dispersion of PAR nanofibers. The prepared PAR fibers could reach 155.2 nm in diameter and exhibited a notable aspect ratio; the observed lengths of these fibers exceeded 15 μm, with aspect ratios surpassing 96.7. Prior to reaching a temperature of 400 °C in a nitrogen atmosphere, the PAR nanofibers did not display significant weight loss, indicating excellent thermal stability. Furthermore, the PAR nanofiber membranes displayed exceptional mechanical properties, with a tensile strength reaching 139.1 MPa.