Exocomposite nanofibers

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 incorporation of nanofibers with smaller nanoparticles can be classified into two different categories, which also means two different approaches. The first one is to embed nanoparticles into nanofibers. In this case, the aim is to reinforce or functionalize nanofibers. The other one is the group of exocomposites or decorated nanofibers where nanopart-... 

Another group of composite nanofibers are decorated or exocomposite nanofibers which are particularly developed for biomedical and sensor applications. The nanoparticles are located at the surface of nanofibers, which can lead to ultra-fast drug release, but do not play reinforcing role. 

Exocomposite nanofibers can be processed by different methods. For example, nanoparticles are electrosprayed on the forming fibers. The other possibility is to carry out electrospinning in a dusty environment. Nanoparticles can be stuck to the surface of the... 

Figure 6.14 Nylon-6/MWCNT exocomposite nanofibers showing surface-embedded CNTs (a) after exposure to CNT soiution and (b) after sonication for 10min in deionized water. Reproduced with permission from H. S. Kim et al. (2006). Copyright 2006. John Wiiey Sons.

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