Nano-microfiber Composites For Filtration

Nanofibers prepared by molecular self-assembly are in general not self-supporting and therefore require stabilizing scaffold structures. In fact, a lot of research in the past has been done with su pramolecular self-assembly of molecules forming a network of nanofibers used as organo/hydro gelators. But efforts to use them as a self-standing membrane or as free fibers were not strong. Therefore, the self-assembly of trisamides was also tried on a substrate, i.e., other microfiber non wovens, leading to microenanofiber composites (Fig. 4.4) used for filtration (Weiss et al., 2016).

Polymer/Carbon Nanotube Composite Nanofibers

To improve the compatibility between CNTs and polymers, the surface functionalization of CNTs has been developed (Kharaziha et al., 2014; Molnar et al., 2008; Ra et al., 2005; Mazinani et al., 2009; Yee et al., 2012; Subagia et al., 2014; Diouri et al., 2014). For instance, Kharaziha et al. established a simple strategy to prepare electrospun gelatin/CNT composite nanofibers by using carboxyl acid groupemodified CNTs, and the well-dispersed CNTs aligned along the fibrous axis could be observed (Fig. 3.15B). This work demonstrated CNTs as a component of tough and flexible scaffolds with outstanding electrical properties (Kharaziha et al., 2014). Molnar et al. (2008) synthesized PVA/CNT composite nanofibers with diverse types of CNTs and different functional groups via electrospinning. Furthermore, other synthetic methods such as electrospinning combined with electrospraying and a surface adsorption approach have been developed as well (Xuyen et al., 2009; Kim et al., 2006b; Vaisman et al., 2007; Dai et al., 2011; Rana and Cho, 2011).

Polymer/Fe3O4 Composite Nanofibers

Magnetic NPs have been receiving increased attention with the rapid development of nanotechnology.Among them, Fe3O4 NPs have caused widespread interest owing to their high superparamagnetism as well as facile preparation. Their easy oxidation and resulting decline in magnetic property is a problem, however, which is effectively solved by the dispersion of Fe3O4 NPs in polymer nanofibers. The simplest way to prepare polymer/Fe3O4 composite nanofibers is to disperse Fe3O4 NPs in the polymer solution and subsequently carry out the electrospinning process. Xin et al. successfully fabricated poly(p-phenylene vinylene)/Fe3O4 composite nanofibers via electrospinning of a precursor solution and subsequent thermal conversion (Fig. 3.14A). In addition, the aligned nanofibers can be obtained by employing two parallel magnets as the collector. A variety of polymer/ Fe3O4 composite nanofibers, including PAN/Fe3O4 composite nanofibers, gelatin/Fe3O4 composite nanofibers, etc., have been reported by means of a similar method, and their potential applications in various fields have been studied as well.