In this paper, a novel electrostatic-assisted melt blown process was reported to produce polypropylene (PP) microfibers with a diameter as fine as 600 nm. The morphology, web structure, pore size distribution, filtration efficiency, and the stress and strain behavior of the PP nonwoven fabric thus prepared were characterized. By introducing an electrostatic field into the conventional melt-blown apparatus, the average diameter of the melt-blown fibers was reduced from 1.69 to 0.96 μm with the experimental setup, and the distribution of fiber diameters was narrower, which resulted in a filter medium with smaller average pore size and improved filtration efficiency. The polymer microfibers prepared by this electrostatic-assisted melt blown method may be adapted in a continuous melt blown process for the production of filtration media used in air filters, dust masks, and so on.

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Bicomponent composite fibers, due to their unique versatility, have attracted great attention in many fields, such as filtration, energy, and bioengineering. Herein, we efficiently fabricated polyvinylidene fluoride/polyimide (PVDF/PI) side-by-side bicomponent nanofibers based on electrospinning, which resulted in the synergism between PVDF and PI, and eventually obtained the effect of 1 + 1 > 2. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the morphology and chemical structure of nanofibers, indicating that a large number of side-by-side nanofibers were successfully prepared. Further, the thermal stability, mechanical strength, and filtration properties of PVDF/PI were carefully investigated. The results revealed that the bicomponent nanofibers possessed both good mechanical strength and remarkable thermal stability. Moreover, the mechanical properties of PVDF/ PI were strengthened by more than twice after the heat treatment (7.28 MPa at 25 °C, 15.49 MPa at 230 °C). Simultaneously, after the heat treatment at 230 °C for 30 min, the filtration efficiency of PVDF/PI membrane was maintained at about 95.45 ± 1.09%, and the pressure drop was relatively low. Therefore, the prepared PVDF/PI side-by-side bicomponent nanofibers have a favorable prospect of application in the field of medium- and high-temperature filtration, which further expands the application range of electrospun fiber membranes.

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For effective application of electrospinning and electrospun fibrous meshes in wound dressing, we have in situ electrospun poly(vinyl pyrrolidone)/iodine (PVP/I), PVP/poly(vinyl pyrrolidone)-iodine (PVPI) complex, and poly(vinyl butyral) (PVB)/PVPI solutions into fibrous membranes by a handheld electrospinning apparatus. The morphologies of the electrospun fibers were examined by SEM, and the hydrophobicity, gas permeability, and antibacterial properties of the as-spun meshes were also investigated. The flexibility and feasibility of in situ electrospinning PVP/I, PVP/PVPI, and PVB/PVPI membranes, as well as the excellent gas permeabilities and antibacterial properties of the as-spun meshes, promised their potential applications in wound healing.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2733-9) contains supplementary material, which is available to authorized users.