Crimped polymer nanofibres by air-driven electrospinning

Electrospinning is a well-known process for producing sub-micron scale polymer filaments through an electrostatic field. This paper presents a very simple “confined” air-driven electrospinning system, in which polyamide nanofibres are produced in the form of continuous crimped filaments. The reported system consists of a vertical cylinder with a weak tangential air-flow feeding from the top, placed between the capillary source electrode and the grounded target collector. The air-flow drives the polymer jet inside the electrostatic field, curls up the filament and reduces the deposition area on the collector surface. Numerical evaluations of both the electrostatic field and the air-flow path within the chamber are reported. The proposed configuration has been successfully tested electrospinning a solution of polyamide-6 in formic acid, varying the applied voltage and the distance between the electrodes. SEM observations of the electrospun fibres revealed that a large amount of crimped nanofibres was produced free from bead defects.