Controlled continuous tapering chitosan-poly(ethylene oxide) nanofibers using a differential voltage regulation in near-field electrospinning

This paper reports a differential voltage regulation (DVR) via near-field electrospinning (NFES) to obtain continuous tapering chitosan-poly(ethylene oxide) nanofibers with decreasing diameters of 1000 to 250 nm. The key parameters were applied differential voltage in the range of 800 to 400 V and voltage regulation time at 1-3 seconds. A controlled continuous deposition chart has been experimentally constructed and parallel nanofibers as well as grid patterns with decreasing diameters are successfully obtained via the low-voltage operation of 400 V. Both DVR and low-voltage regime minimize bending instabilities and patterning perturbations of polymer jet inevitably encountered in higher voltage ranges of conventional far-field electrospinning. In addition, we have successfully demonstrated the feasibility to continuously pattern nanofibers on two-dimensional (2D) and three-dimensional (3D) substrates. This novel yet simple fabrication route will promise the use of electrospun nanofibers based interconnection and customized patterning for advanced fabrics such as biomimic scaffolds in tissue engineering.