Unexplored Green Solvent Systems for The Preparation of electrospun PLA and PCL functional Membranes: Overcoming Technological Lock-In

Abstract

Electrospinning enables the fabrication of nanofibrous membranes with high surface area, tunable porosity, and good mechanical performance. Nevertheless, the vast majority of studies still rely on potentially carcinogenic solvents, such as chloroform (CHF) and dichloromethane (DCM), particularly for polymers like polylactic acid (PLA) and polycaprolactone (PCL). This use reflects a technological lock-in, where hazardous protocols persist despite well documented risks for human health and environment. In this study, acetone, ethanol, and water were investigated as green or green-acceptable alternatives to commonly used solvents for producing electrospun functional membranes. Thermodynamic compatibility was first assessed using Hansen Solubility Parameters (HSP), and their experimentally validated by evaluating solution stability and processability under standard electrospinning conditions. Rheological and morphological analyses confirmed that green solvent-based solutions with adequate proportions allowed producing fibers are comparable to the membrane prepared using hazardous solvent, with additional tunability in terms of fiber diameter and overall morphology. Mechanical testing and wettability measurements further showed properties that are fully comparable to the reference systems, while functional oil absorption tests demonstrated capacities up to 25 g/g with confirmed reusability over five cycles. Finally, the study provides evidence that the long-standing solvent lock-in in electrospinning can be realistically overcome. Crucially, this was achieved without altering the standard process parameters and while obtaining membranes with comparable performances, or in some cases superior, to those fabricated with hazardous solvents.