Methods, apparatus, and systems for fabrication of polymeric nano- and micro-fibers in aligned configurations

A method of preparing a bead-free, high aspect ratio polymeric fiber comprising:

• determining an entanglement concentration (Ce) for a first polymer solution comprising a first polymer and a first good solvent for the first polymer;
• feeding the first polymer solution comprising the first polymer having a concentration of at least Ce in the first good solvent for the first polymer through a spinneret to produce an extruded droplet of polymer solution at a tip of the spinneret;
• contacting the extruded droplet of polymer solution with a target at a contact point;
• moving the contact point away from the spinneret, thereby pulling a high aspect ratio polymeric fiber from the extruded droplet of polymer solution at the tip of the spinneret;
• and
• further pulling the fiber from the extruded droplet of polymer solution at the tip of the spinneret and feeding the first polymer solution through the spinneret into the extruded droplet of polymer solution at the tip of the spinneret at a rate sufficient to compensate for an amount of the first polymer solution used to produce the fiber, thereby producing a bead-free, high aspect ratio polymeric fiber.