Novel optimised highly aligned electrospun PEI-PAN nanofibre mats with excellent wettability

Abstract

This study comprehensively optimised the parameters for electrospinning a polyetherimide (PEI) and polyacrylonitrile (PAN) blend to obtain highly aligned (~93%) nanofibres (NFs) mats with an average diameter of ~150 nm. The formation of smooth, constant, and bead-free NFs was observed as the concentration of the PAN solution hosted in the PEI solution increased beyond 50%. To reduce the NFs diameters, the following optimised parameters were used: 20% humidity (ranges from 20% to 60%), 19 kV applied voltage (ranges from 13 to 24 kV), 0.6 mL/h flow rate (ranges from 0.3 to 1.5 mL/h), 150 mm of needle-tip-to-collector distance (ranges from 100 to 300 mm), 2500 rpm of collector speed (ranges from 0 to 2500 rpm), and the other parameters were maintained constant. The fabricated PEI-PAN NFs were characterized by field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and contact angle (CA) measurement to analyse the morphology of the fibres, study their thermal properties, and to confirm the PEI-PAN blending and wettability, respectively. The detailed morphological studies from the FE-SEM images showed the influence of the parameters on the fibres diameter and alignment. The TGA and FTIR results showed an enhancement in the thermal properties of samples S2 (e.g. 75% PEI-25% PAN), S3 (e.g. 50% PEI-50% PAN), and S4 (e.g. 25% PEI-75% PAN) as compared to S5 (e.g. 0% PEI-100% PAN) and good blending between PEI and PAN. The wettability study confirmed the hydrophilic nature of the PEI-PAN blend while considering the orientation of the NFs as the key factor that determines the fusing of the water drops on the NFs mats. The results showed that the water drops on the aligned oriented NFs mats did not fuse even after 60 s and remained at a contact angle of 28.6°. The high alignment and small diameters of the PEI-PAN NFs with good wettability could have potential applications in fields including as biomedical, and environmental as well as in separation processes.