Electrospinning of Sub-100 nm Polyetherketoneketone Fibers

Diameter refinement of electrospun nanofibers is of great importance toward a broad spectrum of research and commercial applications. However, it is still challenging to realize the spinning of ultrafine nanofibers by simply optimizing the spinning parameters. Here, we realize a stable electrospinning of sub-100 nm fiber for polyetherketoneketone (PEKK), where its high molecular topologicity and chain rigidity lead to strong entanglement between polymer chains and thus open an evident spinning window toward uniform and continuous nanofibers with diameters just ranging from 20 to 80 nm. Such an effect is ascribed to the rich ketone groups and their randomly appearing para and meta positions along the chain backbone. The PEKK nanofibrous membrane exhibits a high tensile strength of 9.5 MPa, rich pores with a size of 0.1–0.5 μm, and high-temperature stability. It can be used as a superior filter membrane, with filtration efficiency higher than 99.9 and 98.0% at room temperature and 300 °C. This study successfully fabricated ultrafine fibers with diameters refined below 100 nm based on strong interchain entanglement, significantly optimizing the filtration performance of the membrane.