Nanofibers nanoparticle embedded

FIGURE 8.8 High-resolution TEM image of a single MgO nanoparticle embedded on the surface of a PEO nanofiber. (Hussain, M.M. and Ramkumar, S.S., 2006, Functionalized nanofibers for advanced applications, Indian J. Fiber Text. Res., 31, 41-51.)... 

FIGURE 8.10 A schematic representation of the overall synthetic procedure for the fabrication of polymer nanofibers with embedded silver nanoparticles, including TEM and SEM images. (Adapted from Kong, H. and Jang, J., Oiem. Comm., 28, 3010, 2006.)... 

Zhang L, Cheng B, Samulski ET. In situ fabrication of dispersed, crystalline platinum nanoparticles embedded in carbon nanofibers. Chem Phys Lett 2004 398 505-10. 

Liu J, Tang K, Song K et al (2013) Tiny Li4Ti50i2 nanoparticles embedded in carbon nanofibers as high-capacity and long-life anode materials for both Li-ion and Na-ion batteries. Phys Chem Chem Phys 15 20813-20818... 

Wang J, Li W, Yang Z et al (2014) Free-standing and bindCT-fiee sodium-ion electrodes based on carbon-nanotube decorated Li4Ti50i2 nanoparticles embedded in carbon nanofibers. RSC Adv 4 25220-25226... 

Hwang SH, Kim C, Jang J (2011) Sn02 nanoparticle embedded Ti02 nanofibers-highly efficient photocatalyst for the degradation of rhodamine B. Catal Commun 12(11) 1037-1041. doi 10.1016/j.catcom.2011.02.024... 

Nam SH, Shim H-S, Kim YS, Dar MA, Kim JG, Kim WB (2010) Ag or Au nanoparticle-embedded one-dimensional composite Ti02 nanofibers prepared via electrospinning for use in lithium-ion batteries. ACS Appl Mater Interfaces 2 2046-2052... 

There is a range of applied voltage values where a stable jet is obtained for PEO solutions. For example, in solutions at 6 wt.%, a stable jet is formed between 5 and 15 KV, with a working distance of about 12.5 cm. It is also possible to obtain poly[acrylonitrile-co-vinylacetate [P[AN-co-VAc]] nanofibers embedded with magnetic Fe203 nanoparticles by the use of P[AN-co-VAc]/Fe203 core-shell nanocapsules applying 15 kV with the feed rate of 0.6 mL/h and the distance of 15 cm. [Fig. 1.11]. ... 

Transmission electron microscopy (TEM] image of P(AN-co-VAc]/Fe203 nanoparticles and nanofiber embedded with magnetic nanoparticles. Reprinted with permission from Ref. 39, Copyright 2015, Taylor Francis. 

Figure 2.4 XRD patterns of Ag/PAN fibers after chemical reduction for 30 min in a N2H5OH aqueous solution. Note thatx denotes the molar ratio of AgNOg/PAN and (inset) TEM image of single PAN nanofibers embedded with Ag nanoparticles. Reprinted with permission from Ref. 54. Copyright 2010, Springer Science+Business Media, LLC.

Surface-active agents can be embedded in a nanofiber membrane by chemical functionalization, by postspinning modification, by physical adsorption, or by nanoparticle polymer composites. 

CdS QDs and quantum wires were successfully embedded in polymeric nanofibers of PEO [42], PAN [40], PMMA [43] and Zein [41], although a surface modification of the nanoparticles (e.g., capping with organic molecules) was in most cases applied to prevent nanoparticle agglomeration, thus improving the quality of the dispersion in the polymer solution [40, 42, 43]. 

When oleic acid-capped CdS quantum wires were embedded in electrospun PEO nanofibers, an unidirectional ahgnment of free-standing quantum wires was realized [42], which was attributed to the sink-like flow at the start of the electrospinning process (Fig. 4). Hydroxyl-coated CdS nanoparticles (CdS-OH) with a uniform size of 5 nm were embedded in PAN nanofibers by electrospinning and an even dispersion was obtained, due to effective protection of the CdS-OH nanoparticles by PAN macromolecules through hydrogen bonding interactions [40]. 

Fouda MMG, El-Aassar MR, Al-Deyab SS. Antimicrobitd activity of ctuboxymethyl chito-san/polyethylene oxide nanofibers embedded silver nanoparticles. Carbohydr Polym. 

A great majority of the composite nanofibers are of a conventional structure where tiie nanoparticles are contained within tiie matrix of the nanofiber. However, anotiier class of composites (referred to here as exocomposites for convenience) consists of the nanoparticles partially embedded in and decorating the surface of the nanofibers. These might be prepared by posttreatment of tiie nanofiber or by electrospinning in a dusty environment, allowing nanoparticles to come into contact witii the moist elongating jet. These decorated nanofibers may be of interest in applications such as the rapid delivery of poorly soluble bioactive materials via a water-soluble nanofiber exocomposite mat, in optical devices, or as chemical/biological sensors. These will be briefly discussed at tiie end of the chapter. 

The approach is illustrated hy nanocomposite fibers of nanoparticle-Fe/ carbon. Nanofihers of PAN were electrospun from DMF (6.7 wt%) solutions containing 3.3 wt% of dissolved ferric acetylacetanoate. Subsequent carbonization of the nanofihers in an inert (Ar and H2) atmosphere (Hou and Reneker 2004) at high temperatures yielded carbonized nanofihers with nanoparticles of elemental iron. These were in the size range of 10-20 nm for the most part and were embedded on the surface of the fibers. Essentially, the same approach was also used with polycarbonate (PC)-palladium acetate solutions, but on calcination of the electrospun polymer nanofihers yielded inorganic palladium oxide nanofibers (Viswanathamurthi et al. 2004a) rather than Pd-nanoparticle/PC. The oxygen in keto groups of the PC was speculated to have reacted with the metal acetate to yield the oxide. Palladium nanoparticles are of particular interest in industry because of their potential use in catalysis (Briot and Primet 1991). 

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