Micromixing with In-Flight Charging of Polymer Solutions in a Single Step Enables High-Throughput Production of Micro- and Nanofibers.

Controlled ejection of liquids at capillary scales is a ubiquitous phenomenon associated with significant advances in, for instance, molecular biology or material synthesis. In this work, we introduce a high-throughput approach, which relies on a micromixing mechanism to eject and fragment viscous liquids, for production of microfibers from poly(vinyl alcohol) solutions. First, filaments were generated pneumatically with a so-called flow-blurring atomizer and using liquid flow rates of up to ∼1 L/min. Subsequently, the filaments were ionized online by corona discharge and consecutively manipulated with an electric field created by disc electrodes. Such charging of the filaments and the effect of the electric field allowed for their ultrafast elongation and diameter reduction from 150 μm down to fibers of 500 nm, which after collection exhibited fabric-like texture. The approach presented herein is a general procedure with potential for scalability that, upon proper adaptation, may be extended to various polymeric materials.