Electrospinning Ethanol–Water Solutions of Poly(Acrylic Acid): Nonlinear Viscosity Variations and Dynamic Taylor Cone Behavior

Electrospinning of polymer solutions is a multifaceted process that depends on the careful balancing many parameters to achieve desired outcome, in cases including mixtures multiple solvents. A systematic study how solution viscosity η—a good probe solvent–polymer interactions—and electrospinnability change when poly(acrylic acid) (PAA) dissolved ethanol–water at varying mixing ratio carried out. pronounced maximum found η water-to-ethanol molar about 2:1, where solvent mixture deviates maximally from ideal behavior and partial deprotonation carboxyl groups by water coincides synergistically with dissolution uncharged protonated PAA fraction ethanol. The concentration tuned as function water–ethanol obtain common value for all suitable electrospinning. For high content, Taylor cone grows volume over time despite minimum flow rate, even experiencing surface gelation ethanol-rich solutions. This attributed hygroscopic nature PAA, drawing excess into air during spinning.