Airflow Dynamics for Multistage Polymer Jet Stretching for the Preparation of Melt-Blown Nanofibers: Implications for High-Quality-Factor Air Filtration

Nanofibers underpin the development of lightweight structural composites, flexible optoelectronic components, and high-performance filtration systems. Yet, most melt-driver jets undergo only single-stage drawing into a decaying aerodynamic force, limiting nanoscale refinement. Here, a multistage polymer jet stretching mechanism is identified in a self-coupled melt-blown process arising from airflow self-organization and coupled redistribution of momentum and heat. Computational fluid dynamics simulations reveal a dual-peak velocity structure and an extended high-temperature region, while a two-phase flow simulation with non-Newtonian rheology resolves the cross-scale evolution and reveals the secondary refinement behavior. Dynamic interception experiments directly record this secondary refinement behavior, where fiber diameter decreases from 1.753 μm to 140 nm. A dual-scale network with over 80% nanofiber content was prepared using this method. The resulting nonwovens reach a 0.1305 quality factor, which is 2.4 times that of traditional melt-blown. This method achieves over 50% refinement in PP, PLA, and bio-PA56, demonstrating a broad material applicability and industrial scalability. Overall, SCAMB enables high-throughput melt-blown nanofiber production with a high nanofiber fraction and an enhanced quality factor, highlighting its potential as an electret-free route to high-performance filtration media.