Surfactant-assisted electrospinning of alginate-rich sodium alginate/poly(ethylene oxide) nanofibers: formulation effects and multi-needle processability.

Abstract

Sodium alginate (SA) is a renewable polysaccharide with high potential for water-based electrospinning, yet the fabrication of nanofibers with high SA content remains challenging due to insufficient chain entanglement, high conductivity and unfavorable jet solidification. In this study, SA/poly(ethylene oxide) (PEO) blends were used as a model system to investigate how non-ionic surfactants and glycerol affect solution properties, fiber morphology, mechanical performance and multi-needle processability. Increasing the SA/PEO ratio from 1:1 to 2:1 enabled the production of alginate-rich fibers containing approximately 80 wt% SA in the dry polymer fraction. The combination of Tween 20 and Pluronic F-127 reduced surface tension and improved fiber uniformity. Glycerol showed a concentration-dependent effect: at 1 wt%, continuous fiber formation was maintained, whereas higher glycerol contents promoted fiber fusion and disturbed deposition. The formulation containing 1 wt% glycerol produced uniform fibers with an average diameter of 214 ± 36 nm under single-needle conditions. In the scale-up mechanical tests, the glycerol-containing formulation showed higher fracture strain than the corresponding formulation without glycerol, whereas tensile strength did not differ significantly between the groups. Transfer to a 20-needle setup with a rotating collector enabled the formation of thicker mats but also revealed local fiber merging and limitations in fiber solidification during multi-needle processing. These results show that surfactant-assisted electrospinning can support the formation of alginate-rich SA/PEO nanofibers, while successful transfer to multi-needle processing requires simultaneous control of solution properties, fiber solidification and deposition conditions.