Bottom-Up Strategy toward Heterocyclic Aramid Nanofibers and Their Application in Strengthening Poly(p-phenylene benzodioxazole) Paper via Constructing a Bilayer Asymmetric Structure

Polymer nanofibers have shone brilliantly in preparation of functional materials by hierarchical self-assembly. Exploring a facile and efficient method to develop high-performance nanofibers is urgently needed but extremely challenging. Herein, we demonstrate a bottom-up strategy for the preparation of heterocyclic aramid nanofibers (HANFs) by hydrogen bonding and shear field-induced self-assembly. This innovative approach dramatically reduces the preparation time of nanofibers from 2 weeks to 1 h. Moreover, due to the introduction of benzimidazole heterocycles that increase the hydrogen bond density, HANFs exhibit excellent paper-forming properties, such as ultrahigh strength (269.6 MPa), modulus (10.9 GPa), and heat resistance (515.6 °C) and therefore show extraordinary potential for enhancing poly( p -phenylene benzodioxazole) (PBO) paper. Excitingly, the bilayer asymmetric PBO/HANF composite paper constructed here demonstrates tremendously improved performance due to the unique interfacial interlocking. This work is believed to provide guidance for the design and manufacture of high-performance nanofibers and specialty insulating paper.