Maghemite (γ-Fe2O3) Fiber-in-tube And Tube-in-tube Nanostructures

Inspired by the nanowire-in-microtube structure, Jian-guo Guan and colleagues proposed a facile and effective nonequilibrium heat-treatment approach combined with electrospinning for fabrication of maghemite (γ-Fe2O3) fiber-in-tube and tube-in-tube nanostructures. The pre cursor was composed of PVP and iron citrate. Fig. 5.21 shows SEM images and corresponding TEM images of as-obtained γ-Fe2O3 fiber-in-tube and tube-in-tube fibers. The figure reveals that the tips of the inner structures are totally separated from the outer tube, and the inner and outer tubes have a closed end. The resultant γ-Fe2O3 fiber-in-tube and tube-in-tube nanostructures may have important applications in a number of fields, such as magnetic separable catalysts or catalyst-supporting mate rials, sensors, absorbents, microreactors, and so forth, because of their structural characteristics and good magnetic properties. This method can intentionally control the contraction direction of the precursor nanofibers during the heat-treatment process by adjusting only heating rate (R) of the calcination, as R can be easily utilized to tune the temperature gradient established in

Coaxial Cojetting Electrospinning Method

Because they have heterogeneous components and anisotropic properties, Janus fibers have wide applications in many fields. As a typical technique, side-by-side electrospinning has been proven to be a facile and cost effective method for preparing Janus fibers. But this method can be used only for fabricating dual-paratactic fibers. Based on this, Joerg Lahann et al. reported a coaxial cojetting electrospinning method with dual core flows and triple core flows. Using this method followed by crosslinking, microsectioning, and shell removal, Janus microcylinders and triple paratactic microcylinders composed of different polymers were prepared (Fig. 5.19A). Fig. 5.19B shows the cross-sectional CLSM images of triple coreeshell fibers. Blue, green, and red channels represent poly(vinyl cinnamate)(PVCi), PEO, and PMMA, respectively. Uniquely shaped building blocks can be fabricated by photopatterning of one hemisphere of the microcylinders. This approach can result in Janus coreeshell fibers and triple coreeshell fibers, where the core is defined by the parallel center jets. In all experiments, a PLGA solution was used as the shell stream, which governs the jetting performance and acts as a

Side-by-side Electrospinning Method

In 2015, White and Yu’s group further studied and developed the side-by-side electrospinning method by regulating the angle between the two needles of the spinneret. By varying the angle, the width, interfacial area, and volume of each side would also be changed. Therefore, different Janus nanofibers with adjustable structures were obtained. The diagram of the spinneret is shown in Fig. 5.17A, and the angle marked q could be tuned to change the morphology of the fibers. The solutions in this work were mainly PVP K-60/rhodamine B and Eudragit@L100/8-anilino-1-naphthalenesulfonic acid ammonium salt in a mixture of ethanol and DMAc. For the side-by-side electrospinning, the two solutions were stretched from their own needles with the same electrostatic charge and came together at the outlet of the nozzle. With their mutual electrostatic repulsion, the two solutions may separate from each other, which would lead to a failure to form the side-by-side structure. In this research, however, arranging the angle between the two ports to some suitable value would contribute to the fabrication of the side-by-side structure. The corresponding TEM images for when the values of the angle q were 40, 50,

CENTRIFUGAL ELECTROSPINNING MACHINE

More spinnable material;

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Precious feeding pump: supplying liquid continuously.

Electrospun Bifunctional Janus Nanobelts

In 2014, electrospun bifunctional Janus nanobelts were fabricated by Dong and coworkers (Ma et al., 2014). The setup is shown in Fig. 5.16A. Nanobelts are characterized by anisotropy, large width/ thickness ratio, and unique optical, electrical, and magnetic properties that are different from those of nanofibers. The side-by-side nanofibers these authors made included Fe3O4/PMMA as one side, while the component of the other side was Tb(BA)3phen/PMMA. The SEM image of the nanobelts obtained by side-by-side electrospinning is shown in Fig. 5.16BeD shows the EDS line scan analysis of the nanobelts, which confirmed the morphology of side by side. Compared with the Fe3O4/Tb(BA)3phen/ PMMA composite nanobelts, the biphasic Janus nanobelts possessed both high fluorescence intensity and saturation magnetization.

QZP 1 Portable Electrospinning Apparatus

QZP - 1 portable electrospinning apparatus is researched,  developed and produced by Foshan Lepton Precision M&C Tech Co.,Ltd., , dedicated to the laboratory of portable handheld device, its size is equivalent to mobile phones, small and light, easy to carry, can be used in the early stage of the electrospinning experiment, classroom demo or innovative experiments, can also be applied to wound dressing preparation, in a timely manner to protect the wound.

Electrospinning Nanofibers Having a Core-sheath Structure

Li and Xia fabricated hollow fifibers made of titania by coaxial electrospinning through a two capillary coaxial spinneret and subsequent extraction of mineral oil as well as calcination of the core, in 2004. This group solved the instability problem by coelectrospinning two immiscible solutions, followed by gelation (or crosslinking) and stabilization of the sheath. In this work, an ethanol solution containing a solegel precursor, an acid catalyst, and a polymer was loaded into the sheath capillary, while heavy mineral oil was loaded into the core capillary. When the correct viscosities and rates of hydrolysis were achieved as stable bicomponents, a Taylor cone was formed, resulting in a stable coaxial jet. One of the major obstacles involved in the formation of core-sheath or hollow nanofifibers is the instability of the core. With the addition of a solegel precursor, gelation in the outer surface of the sheath during the spinning process prevented structural breakdown and resulted in fifibers with a stable morphology. Hollow fifibers could be obtained by extracting the mineral oil core with a solvent such as octane. As shown in Fig. 5.8A, the setup for