Nontoxic, Eco-Friendly, Low-Cost Spinning of Submicrometric Fibers from Water-Soluble Polymers Using Protic Ionic Liquids

Abstract

Ionic liquids (ILs) are widely utilized in various scientific fields and technologies, offering environmentally friendly alternatives to toxic volatile solvents. In particular, protic ionic liquids (PILs), a subset of ILs, boast advantages such as simple synthesis, low cost, and biodegradability. ILs are promising solvents for electrospinning, enabling the production of high-quality nanometric fibers. Despite their potential, challenges persist in electrospinning polymer solutions containing ILs or poly(ionic liquid)s, mainly due to changes in solution conductivity, leading to rheological alterations and jet instabilities. In contrast, Solution Blown Spinning (SBS) offers a solution to these challenges, employing a pressurized air system without electric fields and ensuring a high rate of fiber production. This study aims to produce polymeric submicrometric fibers by leveraging the benefits of ILs as additives, along with the practicality and adaptability of the SBS technique. Twelve compositions of poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) using 2-hydroxydiethylammonium propionate (2-HDEAPr) PIL were spun and characterized by SEM, FTIR, and DSC analyses. The addition of 0.25 mL of PIL was sufficient to reduce the average diameter compared to pure fiber, due to the plasticizing effect of the additive. The findings confirm the feasibility of fiber production by SBS, highlighting fiber smoothness, alignment, and continuity. The average fiber diameters measured were 0.55, 0.66, and 0.91 μm, respectively, for PVA-0.25 mL, PVA-0.50 mL, and PVA-1 mL PIL. Additionally, PVP compositions exhibited an average diameter of approximately 0.40 and 0.55 μm. Such results indicate the potential of these aqueous solution blow-spun fibers for the development of eco-friendly fibrous materials.