PVdF nanofiber membranes loaded with GO were prepared via an electrospinning method and they showed excellent performances including low fouling due to hydrophilic property of GO.

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In this study, a series of novel modified graphene oxide (MGO)/polyacrylonitrile (PAN) hybrid nanofiber membranes were fabricated by electrospinning a PAN solution containing up to 1.0 wt.% MGO. The GO was initially prepared by a time-saving improved Hummer’s method. Subsequently, the formation of GO was confirmed by scanning electron microscopy (SEM), AFM, Fourier-transform infrared spectroscopy (FT–IR), and Raman spectroscopy. This study also prepared the modified GO with polydiallyldimethylammonium chloride (GP) by using a simple surface post-treatment method to improve its dispersion. Varying amounts of GP were incorporated into PAN nanofibers for the better properties of GP/PAN nanofibers, such as hydrophilicity, mechanical properties, and so on. The resulting GP/PAN hybrid nanofiber membranes were characterized by SEM, FTIR, contact angle, and thermal and mechanical properties. These results showed that the hydrophilic and mechanical properties of GP/PAN hybrid nanofiber membranes were dramatically improved, i.e., 50% improvement for hydrophilicity and 3–4 times higher strength for mechanical property, which indicated the possibility for water treatment application. In addition, the notably improved thermal stability results showed that the hybrid nanofiber membranes could also be a potential candidate for the secondary battery separator.

Silver nanoparticle-modified graphene oxide (Ag/GO) was reliably prepared by using sodium borohydride (NaBH4) in the presence of citric acid capping agent via a simple wet chemistry method. This rapidly formed Ag/GO composite exhibited good dispersity in a solution containing hydrophilic polyacrylonitrile (PAN). Subsequent electrospinning of this precursor solution resulted in the successful formation of nanofibers without any notable defects. The Ag/GO-incorporated PAN nanofibers showed thinner fiber strands (544 ± 82 nm) compared to those of GO-PAN (688 ± 177 nm) and bare-PAN (656 ± 59 nm). Subsequent thermal treatment of nanofibers resulted in the preparation of thin membranes to possess the desired pore property and outstanding wettability. The Ag/GO-PAN nanofiber membrane also showed 30% higher water flux value (390 LMH) than that of bare-PAN (300 LMH) for possible microfiltration (MF) application. In addition, the resulting Ag/GO-PAN nanofiber membrane exhibited antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Furthermore, this composite membrane exhibited outstanding anti-fouling property compared to the GO-PAN nanofiber membrane in the wastewater treatment. Therefore, the simple modification strategy allows for the effective formation of Ag/GO composite as a filler that can be reliably incorporated into polymer nanofiber membranes to possess improved overall properties for wastewater treatment applications.

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Exfoliated graphene oxide (GO) was reliably modified with a cetyltrimethylammonium chloride (CTAC) surfactant to greatly improve the dispersity of the GO in a polyacrylonitrile (PAN) polymer precursor solution. Subsequent electrospinning of the mixture readily resulted in the formation of GO–PAN composite nanofibers containing up to 30 wt % of GO as a filler without notable defects. The absence of common electrospinning problems associated with clogging and phase separation indicated the systematic and uniform integration of the GO within the PAN nanofibers beyond the typical limits. After thoroughly examining the formation and maximum loading efficiency of the modified GO in the PAN nanofibers, the resulting composite nanofibers were thermally treated to form membrane-type sheets. The wettability and pore properties of the composite membranes were notably improved with respect to the pristine PAN nanofiber membrane, possibly due to the reinforcing filler effect. In addition, the more GO loaded into the PAN nanofiber membranes, the higher the removal ability of the methylene blue (MB) and methyl red (MR) dyes in the aqueous system. The adsorption kinetics of a mixed dye solution were also monitored to understand how these MB and MR dyes interact differently with the composite nanofiber membranes. The simple surface modification of the fillers greatly facilitated the integration efficiency and improved the ability to control the overall physical properties of the nanofiber-based membranes, which highly impacted the removal performance of various dyes from water.

Electrospun composite nanofiber mats consisting of polyurethane (PU) and nontoxic tungsten powder are manufactured via electrospinning for use as X‐ray shielding materials. Upon systematical formation of tungsten‐PU composite nanofiber layers, heat and pressure are simultaneously treated to design light‐weight mats containing various amount of tungsten metals. After examining their structural and physical properties, the X‐ray mass attenuation coefficient, nitrogen permeability, and flexibility of the resulting mats are compared to conventional film‐type shielding mats. While the nanofiber‐based composite mats still exhibit a comparable X‐ray mass attenuation coefficient (9.64 cm2/g), their gas permeability (8.56 L/min) and flexibility (bending angle of 28.8°) are almost two and five times higher than those of conventional mats, respectively. This work clearly demonstrates the preparation of effective composite mats with controlled properties for the development of nontoxic shielding suits that can replace conventional lead‐based materials possessing environmental and health concerns.