Research on the stable spreading mechanism of the droplet and analysis on the spinnability of a novel electrospinning nozzle based on radially splayed multiple vanes

Abstract

Electrospun nanofibers have gained much interest recently because of their adjustable porous structure, high specific surface area, and large number of active sites, further enhancing the performance of nanofiber materials, which are prepared in laboratories using the needle electrospinning method most frequently. However, the issues in the needle electrospinning process, such as liquid clogging on the needle tip and droplet dripping/splashing, have negative effects on the production, morphology, structure, and property of the electrospun nanofibers. In this paper, a novel electrospinning nozzle based on radially splayed multiple vanes was proposed to solve the problems existing in the capillary needle electrospinning process. The spreading status and holding time of the droplet on the nozzle tip were theoretically addressed through a series of mathematical calculations and derivations. The spinnability of the PAN solution on the novel nozzle was tested to investigate the spinnable concentration range. The experimental results showed that the novel nozzle with an approximate 38.5° splaying angle can promote the full spreading of the droplet up to a diameter of ∼8 mm and prolong the droplet dripping time exceeding 123 s for a 10 wt. % PAN solution. The spinnable viscosity of the novel nozzle could reach 143 Pa s, which was nearly four times that of the conventional capillary needle. In addition, the multiple jets could be inspired in electrospinning by the novel nozzle and the nanofibers prepared were featured with a fine diameter of 420 nm and a coefficient of variance value as low as 15%. Both the theoretical analysis and experimental results indicated that the novel nozzle based on radially splayed multiple vanes was capable of optimizing the spreading surface and holding time of the spinning solution, and the solution droplet could be kept stably on the nozzle without dripping and splashing. More importantly, this novel nozzle can broaden the spinnability range of the spinning solution.