Conducting polymer fibers previous studies

The effect of S WNT addition to PANi fibers on conductivity was also investigated (Figure 8). A percolation threshold of 0.35% (w/w) SWNTs was determined using the basic percolation power law [32]. The value for conductivity percolation threshold obtained here is in good agreement with another polymer-nanocomposite system that showed a 0.5 w/w % percolation level [33]. In addition, a significant increase in electrical conductivity was observed even at low SWNTs loadings, while the neat PANi-AMPSA fibers prepared here had similar conductivities ( 500 Scm ) compared to those obtained in a previous study (600 Scm ) [11]. 

As pointed out previously, poly(ethylene terephtha-late) is also largely used in the production of fibers, but this polymer has been blended with conductive polymers only in the form of films. In one study a poly(ethylene terephthalate) film was used as support for the preparation of a blend of poly(methyl methacrylate) and polypyrrole [90]. The poly(ethylene terephthalate) film coated with poly(methyl methacrylate) was immersed in pure pyrrole monomer and transferred to an aqueous FeCl3 solution. Surface conductivities in the range of 100 S cm were... 

The last method to be discussed, which is used to form polymer/ceramic composites by electrospinning, is extremely different to the methods previously described, but worth mentioning. Zuo et al. [129] used a method to create a composite scaffold that is actually the reverse of what most people are doing. Instead of mineralizing the nanofibers, Zuo et al. actually incorporated electrospun polymer nanofibers into a ceramic bone cement in order to form a composite scaffold. It was found that by incorporating electrospun nanofibers into the cement, the scaffold became less brittle and actually behaved similarly to that of a ductile material because of the fibers. Composite scaffolds with different polymers and fiber diameters were then tested in order to determine which scaffold demonstrated the most ideal mechanical properties. However, no cell studies were conducted and this method would most likely be used for a bone substitute instead of for bone regeneration applications. 

From recent studies, cellulose is found to be the most common organic polymer and considered as almost infinite source of raw material to fidfiU the increasing demand for eco-friendly and biocompatible products. It represents about 1A billion tons of the total annual biomass production (Klemm et al. 2005). As fignoceUulosic fibo" becomes vital, many possible plants were tested. Natural fiber not only can be harvested from cotton, wool, and other ancient source, but it covers different varieties and different sources aU over the world. Available natural fiber that has been conducted in previous... 

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