Poly(epsilon-caprolactone) (PCL) biopolymer nanofibers and micro-fibers have been fabricated for the first time at the rates up to 14.0 g per hour using a needleless and collectorless alternating current electrospinning technique. By combining the ac-voltage, "green" low toxicity glacial acetic acid (AA) as the solvent and sodium acetate (NaAc) as an additive, beadless PCL fibers with diameters tunable from 150 nm to 2000 nm, varying surface morphology and degree of self-bundling are obtained. In this new approach, the addition of NaAc plays a crucial role in improving the spinnability of PCL solution and fiber morphology. NaAc reveals the concentration-dependent effect on charge transfer and rheological properties of the PCL/AA precursor, which results in broader ranges of spinnable PCL concentrations and ac-voltages suitable for rapid manufacturing of PCL-based fibers. (c) 2015 Wiley Periodicals, Inc.