Polymeric nanofibers characteristics

When an enantiomer of CSA is used in the polymerization, such as R-CSA, it is possible to create chiral polyaniline nanofibers. Figure 7.20 shows the circular dichroism (CD) spectrum of a water dispersion of as-prepared R-CSA doped polyaniline nanofibers. The positive peak at 450 nm is characteristic of chiral polyaniline [66-70], and is consistent with water s effect on the direction of the CD signals previously observed [71]. The peak at 290 nm is due to excess R-CSA in the dispersion. Recently, Wang et al. discovered that highly chiral polyaniline nanofibers can be produced by incremental addition of the oxidant, ammonium peroxydisulfate, into aniline solution with aniline oligomers and concentrated chiral dopants (>5 M R- or S-CSA) [72]. Chiral polyaniline nanofibers are very interesting for chiral recognition studies [68]. 

Wang, F.G., Wang, M., Topham, PD., and Huang, Y. (2012) Fabrication of magnetic drug-loaded polymeric composite nanofibers and their drug release characteristics. RSC Adv., % 2433—2438. 

The recent interest in using stiff nanometric particles as reinforcement materials in polymeric matrixes, composites, or nanocomposites has been increasing. Two good examples of these types of particles are carbon nanotubes and cellulose nanofibers. Cellulose nanofibers, also reported in the literature as whiskers, nanocrystals, cellulose crystallites, or crystals, are the crystalline domains of ceUulosic fibers, isolated by means of acid hydrolysis, and are called in this way due to theb physical characteristics of stiffness, thickness, and length (Souza and Borsali 2004). 

Chen J, Yang J, Yan X, Xue Q (2010) NH and HCl sensing characteristics of polyaniline nanofibers deposited on commercial ceramic substrates using interfacial polymerization. Synth Metals 160 2452-2458... 

Lee et al. explored the application of zinc oxide nanoparticles to polypropylene nonwoven fabrics via electrospinning as one approach to impart UV-protective properties. In addition, moisture and air vapor transport characteristics of layered clothing systems with various levels of electrospun mat area density are assessed to observe the consequence of electrospun web layers on thermal comfort level of the layered structures (Fig. 14.6c) [56]. Ultrafine cellulose fibers from natural cotton lines, whose degree of polymerization was above 10,000, were electrospun. The cellulose nanotibers treated with the hydrothermal incorporation of Ce02 nanoparticles into the nanofiber substrate surface showed good UV-shielding properties... 

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