Electrospinning optimization for enhanced hydrophilicity and surface functionality of Poly(ε-caprolactone)/Polyethyleneimine nanofibers with embedded Fe3O4 nanoparticles

Abstract

To address the poor hydrophilicity and limited functionality of poly(ε-caprolactone) (PCL) nanofibers, polyethyleneimine (PEI) was incorporated into the electrospinning solution. The process was optimized using response surface methodology (RSM), resulting in nanofibers with an average diameter of 227 nm. Additionally, PEI-coated Fe₃O₄ nanoparticles, synthesized via a one-step hydrothermal method, were embedded into the PCL/PEI nanofibers, producing magnetic nanofibers with a uniform diameter of 197 nm and a saturation magnetization of 22.6 emu/g. The inclusion of Fe₃O₄@PEI nanoparticles reduced the water contact angle by over 50%, significantly enhancing hydrophilicity. To evaluate the nanocomposite’s ability to adsorb negatively charged molecules, the adsorption capacity of Congo red (CR) was tested, achieving 378.88 mg/g for PCL/PEI and 397.43 mg/g for PCL/PEI/Fe₃O₄@PEI. The adsorption followed pseudo-second-order kinetics and Langmuir isotherm models. Reusability tests showed > 90% removal efficiency over five cycles. These results highlight the potential of PCL/PEI-based nanofibers for wastewater treatment and dye removal, making them promising for sustainable environmental remediation.