A breathable piezoelectric poly(vinylidene fluoride) electrospun nanofiber membrane obtained through controlling solution parameters

This study employed electrospinning to prepare PVDF nanofibers and investigated the influence of PVDF concentration and DMF: Acetone ratio on the formation of different phases (α, β, and γ), desired morphology, and piezoelectric properties. XRD and FTIR spectrometer data were analysed to accurately assign and identify specific PVDF phases. A PVDF concentration of 20% (w/v) with a DMF: Acetone ratio 1:1 (20_1:1) exhibited the maximum crystalline phase content of 56.8%. Phase formation was primarily governed by the balance between the surface tension and viscosity, which is controlled by the PVDF concentration and acetone content in the solution. This results further validated by the highest piezoelectric performances of the membrane. SEM micrographs revealed fiber diameter varied from 76 to 86 nm for 15%, 129 to 134 nm for 20% and 230 to 259 nm for 25%. The optimal condition for obtaining maximum β-phase, bead-free nanofibers and with a smooth surface was PVDF concentration of 20% (w/v) with a DMF: Acetone ratio 1:1. A PVDF concentration of 20% and DMF: Acetone ratio of 1:1 yielded a maximum electroactive phase of 82.1% and providing a breathable membrane essential for wearable applications. The methodology and understanding of the underlying mechanism of the desired phase and morphology provide valuable guidelines for optimizing the β-phase and obtaining bead-free fibers in PVDF-based nanocomposites.