#nanofibrous

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How To Fabricate A Graphene Oxide (GO) Thin-film Nanofibrous Composite Membranes By Electrospinning Nanofibers Equipment?

 #graphene #oxide #GO #thinfilm #nanofibrous #composite #membranes #electrospinning #nanofibers #equipment #tunable #nanochannels #nanopores #highly #porous #support #nanosheets #mat #TFNC

 GO has attracted the interest of many researchers for fabricating novel separation membranes owing to their smoothness, atomic thickness, good hydrophilicity, and tunable nanochannels or nanopores. However, GO membranes really show poor stability in water, especially fabricated on highly porous nanofibrous support. Pan and his group first synthesized GO nanosheets with large lateral size (>200 mm) by a newly developed method and successfully assembled them on a highly porous nanofibrous mat using the vacuum suction method. As shown in Figure, the nanochannels, formed by the interlayer spacing between adjacent GO nanosheets, enabled an ultrafast water permeability, which is claimed to stem from a quickly passing hydrophilic “gate” (edges of GO nanosheets or defects in the GO) for aggregation and the fast slip flow along the atomically smooth and hydrophobic carbon walls. Moreover, the GO TFNC membranes showed high rejection performance (nearly 100% rejection of Congo red and 56.7% for Na2SO4).

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How To Fabricate Electrospun Edible Nanofibrous Films and Antimicrobial Nanofibers?

 #fabricate #electrospun #edible #nanofibrous #films #fibers #antimicrobial #activity #silver #nanoparticles #nanofibers

 A study has reported the fabrication of electrospun edible nanofibrous films from a blended solution of CA and egg albumen (EA) (Figure; Table ). The solvents are 85% acetic acid for the CA and 50% formic acid for the EA. Tween 40 is added as a food-grade nonionic surfactant to modulate the solution properties.

 To fabricate fibers with antimicrobial activity, Son et al. have reported the addition of silver nitrate into 10 wt% CA solution dissolved with a mixture of acetone and water (4:1). Afterward, the as-prepared fibers are treated by photoreduction, thereby converting the silver ions into silver nanoparticles with antimicrobial activity. And then the silver nanoparticles diffuse to the surface of the nanofibers to form aggregates, which inhibited the growth of various foodborne pathogens, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa.

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How To Fabricate Starch-based Nanofibrous Mats By Electrospun Nanofibers Machine?

 #starchbased #nanofibrous #mats #electrospun #nanofibers #machine

 The obtained as-spun starch fibers (Fig. A) could be used in the food industry.

Electrospun nanofibers have been fabricated from high-amylose starch blended respectively with palmitic acid, ascorbyl palmitate, and cetyltrimethylammonium bromide (CTAB). Ascorbyl palmitate is a food additive source of vitamin C and an antioxidant. CTAB is an effective antiseptic agent against bacteria and fungi. The obtained inclusion complexes (Fig. B) provide a novel medium to encapsulate varied guest compounds, which expands the application of starch-based nanofibrous mats.

The Wang group has reported electrospun nanofibers of PVA and oxidized starch (Fig. C). Oxidized starch is a kind of cationic polysaccharide, which is ionized under acidic and neutral conditions. The addition of oxidized starch affects the conductivity of the solution, and the diameter of the fiber decreases upon the increase in the conductivity of the solution.

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How To Make A Two-tiered Thin-film Nanofibrous Composite Hemodialysis Membrane By Electrospinning?

 #nanofibrous #composite #hemodialysis #membrane #scaffoldlike #support #layer #TFNC #membranes #nanofiber

 In 2017, Yu et al. attempted a new type of high-performance hemodialysis membrane consisting of an ultrathin hydrophilic active separation layer and a scaffoldlike nanofibrous support layer, as schematically shown in Fig. 14.12. The PVA active separation layer of the two-tiered TFNC membranes could achieve a minimum thickness of the hydrophilic layer, and the open pore structure of the nanofiber support layer favored diffusion and convection. Hence, the uremic toxins, which were dissolved in water, were carried with water and passed through the membrane more easily. This two-tiered TFNC hemodialysis membrane exhibited excellent dialysis performance, especially for the middle-molecule uremic toxin removal. It may break the bottleneck of trade-off (to reconcile the desire for high removal of middle-molecular toxic substances and high retention of big proteins at the same time), which indicates that the two-tiered TFNC membrane has a potentially wide application for hemodialysis. It is imperative to point out that these two-tiered TFNC hemodialysis membranes have not been optimized, and the chosen material system (i.e., PVA for the active separation layer) may not be the most appropriate one for an artificial kidney in practice (e.g., compared with commercially available hemodialysis membranes because of their hollow fiber configuration). Therefore, for the future development of TFNC hemodialysis membranes, other hemodialysis materials and their modification are necessary to achieve better blood compatibility and more efficient dialysis performance.

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How To Produce Thin-film Nanofibrous Composite Ultrafiltration Membrane By Electrospinning Technology?

 #thinfilm #nanofibrous #composite #ultrafiltration #membrane #electrospinning #technology #UF #membranes #micrometers #electrospun #nanofibers #scaffolds

 The demonstrated TFNC UF membranes consist of a three-layered hierarchical structure, as schematically shown in Fig. 14.7. The bottom layer is composed of a nonwoven substrate (e.g., PET nonwoven web), which provides the overall mechanical strength to the membrane. The typical thickness of the bottom substrate is in the range of a few hundred micrometers, having fibers with diameters of about 10-30 mm. This nonwoven substrate has a relatively high porosity (about 40%-60%), a Young’s modulus up to 500 MPa, ultimate tensile strength up to 40 MPa, and an elongation-to-break ratio of around 20%, which provides sufficient elastic property to the membrane. The middle layer is composed of electrospun nanofibers with high porosity and interconnected pores, instead of the conventional microporous membrane prepared by the phaseinversion method. Typically, PAN, crosslinked PVA, PVDF, CA, and other polymers can be employed to fabricate electrospun nanofibrous scaffolds with a typical layer thickness of w50 mm. The thickness of the barrier layer is typically between 100 and 1000 nm, with the pore size ranging from 5 to 50 nm, depending on the application.

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How To Make Micro/nanofibrous Structures Direct Written On An Insulating Substrate

As a mass of charge accumulates on the deposited nanofiber, it is difficult to achieve patterned deposition on the insulating substrate. Zheng et al. demonstrated direct writing of orderly micro/nanofibrous structures on a flexible insulating polyethylene terephthalate (PET) substrate utilizing an AC electrical field. The charge transfer characteristics in the jet are changed and the Coulomb repulsive force from the residual charges on the deposited structure is reduced with the help of the applied AC voltage, as shown in Fig. 9.11A and B. Thus a stable jet can be built up and orderly structures, as shown in Fig. 9.11C, can be collected on the PET substrate. From the experimental results, the minimum motion velocity of substrate required to direct write a straight line is 700 mm/s and the line widths of direct-written fibrous structures are in the range of 10-40 μm.