Nanofibers coaxial

Figure 4.22 (a) SEM photograph PANI/PMMA coaxial nanofibers (electrospun PMMA solution 0.18 g ml ). (b) Photograph of a gas sensor based on PANI/PMMA coaxial nanofibers. (Reprinted with permission from Sensors and Actuators B., Gas sensing properties of a composite composed of electrospun polyfmethyl methacrylate) nanofibers and in situ polymerized polyaniline by S. ji, Y. Li and M. Yang, 133, 644-649. Copyright (2008) Elsevier Ltd)... 

H. Dong, U. Megalamane, and W. Jones Jr. Conductive polyaniline/PMMA coaxial nanofibers fabrication and chemical sensing. Polymer Mater. Sci. Eng., 44(2), 124—125 (2003). 

Rang, H., Ma,L, Li, C., 2012. Polyaniline-Mn02 coaxial nanofiber with hierarchical structure for high-performance supercapacitors. J. Mater. Chem. 22,16939-16942. 

Coaxial nanofibers with the core polymer sheathed by a layer of the same or a different polymer fabricated using an electrospinning technique was first reported by Sun et al. (2003). Figure 9.5 shows the specially engineered tip of concentric capillaries used for the purpose. Homopolymer core-shell nanofibers (e.g., PEO-PEO fibers with the shell containing a dye to contrast it with the core in optical imaging) as well as two-polymer fibers such... 

Zhu, Y., J. C. Zhang, Y. M. Zheng, J. Zhai, and L. Jiang (2006a). Conducting PANI/PAN coaxial nanofibers with tuned wettability. Chemical Journal of Chinese Universities (Chinese) 27(1) 196-198. 

Fig. 7.5 Preparation of cellulose-based coaxial nanofiber separators for lithium-ion battery. Reproduced with permission from Ref. [61] Copyright 2015 American Chemical Society...

FIGURE 2.5 Scanning electron microscopy image of the coaxial nanofiber electrospun from PEO/chitosan—the contrast between the fiber s edges and center reveal the coaxial structure. 

Coaxial nanofibers have several advantages over conventional, single-component fibers. Perhaps the most notable advantage is the ability of coaxial spinnerets to electrospin a usually unsuitable material using an easily spinnable but sacrificial material as a sheath (Zhang et al. 2006 Greiner et al. 2006 Kowalczyk et al. 2008). Similarly,... 

Jiang HL et al (2005) A facile technique to prepare biodegradable coaxial electrospun nanofibers for controlled release of bioactive agents. J Control Release 108(2-3) 237-243... 

Zhang YZ et al (2004) Preparation of core-shell structured PCL-r-gelatin Bi-component nanofibers by coaxial electrospinning. Chem Mater 16(18) 3406-3409... 

Figure 4.3 Schematic Illustration of the set-up used to coelectrospin compound core-shell nanofibers. It involves the use of a spinneret consisting of two coaxial capillaries through which two polymer solutions can simultaneously be ejected to form a compound jet. (Reprinted with permission from Advanced Materials, Compound Core-Shell Polymer Nanofibers by Co-Electrospinning by Z. Sun, E. Zussman, A. L. Yarin eta ., 15, 22, 1929-1932. Copyright (2003) Wiley-VCH)...

Poly[2-methoxy-5-(2 -ethyl-hexyloxy)-l,4-phenylene vinylene] (MEH-PPV) is an excellent conjugated polymer and broadly used in polymer photoelectron devices, but is difficult to electronspin directly. In the work by Zhao et al, core-shell structured nanofibers were fabricated by coaxial electrospinning MEH-PPV (shell) in chlorobenzene and PVP (core) in 1,2-dichloroethane [64]. MEH-PPV was soluble in the above two solvents, which prevented the precipitation of MEH-PPV and enhanced the adhering action between the two polymers in the coaxial electrospinning process. It should be noted that this is an unusual example of core-shell nanofibers where (a nonprocessable) PPV was spun as the shell and not in the core. These uniform core/shell PVP/MEH-PPV nanofibers with a highly fluorescent property can have potential applications in the fabrication of polymer nanophotoelectron devices. 

Coaxial PMMA/PANI composite nanofibers have also been fabricated using the electro-spinning technique and an in situ polymerization method and were then transferred to the surface of a gold interdigitated electrode to constmct a gas sensor (Figure 4.22) [102]. It was... 

Q. Zhao, Y. Xin, Z. Huang, S. Liu, C. Yang, and Y. Li, Using poly[2-methoxy-5-(2 -ethyl-hexyloxy)-l,4-phenylene vinylene] as shell to fabricate the highly fluorescent nanofibers by coaxial electrospinning. Polymer, 48,4311-4315 (2007). 

Considering the effect of nanoparticle morphology on ER effect, well-organized coaxial cable-like titania-coated PANI (PANI titania) nanofibers... 

J.B. Yin, X. Xia, L.Q. Xiang, X.E Zhao, Coaxial cable-like polyanihne titania nanofibers, facile synthesis and low power electrorheological fluid application, / Mater Chem., 2010, 20,7096. 

The electrically charged part and coaxial jet shown in Fig. 1.17 allow to obtain core-shell nanofibers (nanochannels and nanocapsules) by coaxial electrospinning. ... 

Figure 1.17 Common setup and electrically charged part for coaxial jet for electrospinning and core-shell nanofibers nanochannel and capsule by coaxial electrospinning. Reprinted from Ref. 45, Copyright 2010, Fengyu Li, Yong Zhao, and Yanlin Song.

Initially, poly(vinyl alcohol] (PVA] solution was electrospun and further treated with FeCl3 solution to adsorb Fe ions on the nanofibers surface. Later, an EDOT monomer was evaporated and polymerized on the PVA surface, leading to coaxial PVA/PEDOT fibers, which were washed with distillated water, giving 140 nm PEDOT tubes. PEDOT nanotubes achieved electrical conductivity values of 61 S/cm higher than the usual PEDOT nanomaterials... 

Coaxial spinning can be used in producing PANI nanofibers. ... 

---