Abstract
Ethyl cellulose (EC) is one of the most widely used cellulose derivatives. Nevertheless, challenges such as the formation of beaded fibers, low yield, and nonporous internal structure persist in electrospinning, limiting functional improvements and industrial applications. This study invented a groundbreaking high-speed electrospinning technique through sheath liquid assistance to optimize the Taylor cone, dramatically enhancing the yield, morphology, and formation of porous structures of EC nanofibers beyond what has been seen in the literature to date. Our study emphasizes the crucial role of the sheath liquid's physical and chemical properties in controlling the morphology and diameter of EC nanofibers. It was discovered that highly polar and viscous sheath liquids led to the formation of beaded structures. Most importantly, the sheath liquid-assisted method substantially increased the ejection rate of the EC solution tens and hundreds of times compared to the current low-speed electrospinning method (0.1-1 mL/h) by refining the shape of the Taylor cone and resolving low productivity challenges in conventional nanofiber production. Meanwhile, increasing the flow rate of the EC or the sheath liquid accelerated the phase separation of EC solutions, thereby promoting the formation of porous structures in EC nanofibers. A pronounced porous structure was observed when the core EC flow rate reached 25 mL/h or the sheath chloroform flow rate reached 20 mL/h. Furthermore, our sheath liquid-assisted high-speed electrospinning technique demonstrated universal applicability to ECs with varying molecular weights. This study comprehensively addressed challenges in controlling the yield, morphology, and internal structure of EC nanofibers through sheath-solution-assisted high-speed electrospinning technology. These findings provide an innovative approach to developing next-generation electrospinning technologies to enhance the yield and properties of natural polymers for sustainability.