Electrospun nanofiber webs

The electrospun nanofiber webs, with very high surface area to volume ratio and high... 

Another study by Hong et al. also reports the preparation of conducting PANI/nylon-6 composites with high electrical conductivity and superior mechanical properties, such as flexibility and lightness [24]. PANI was chemically polymerized on the surface of the nylon-6 electrospun nanofiber webs. The electrical conductivity measurements showed that the conductivity of the PANI/nylon-6 composite electrospun fiber webs was superior to that of PANI/nylon-6 plain-weave fabrics because of the high surface area/volume ratios. The volume conductivities of the PANI/nylon-6 composite electrospun fiber webs increased from 0.5 to 1.5 S cm as the di sion time increased from 10 min to 4h because of the even distribution of PANI in the electrospun fiber webs. However, the surface conductivities of the PANI/nylon-6 composite electrospun fiber webs somewhat decreased from 0.22 to 0.14 S cm as the di sion time increased, probably because PANI was contaminated with aniline monomers, aniline oligomers, and some alkyl chains, which served as electrical resistants. 

Electrospinning is used for continuous production of electrospun nanofibers webs with high efficiency and discontinuous production of nanofiber webs from a veiy small amount of liquid (one droplet) for expensive pol5miers. Application types of electrospinning are the... 

Of all these methods, the electrospinning process has become the most popular technique over the past two decades, because of the ease of operation and simplicity of equipment compared with others. Ihe process of electrospinning has been known for almost 75 years and the first patent was issued to Formhals in 1934. In the 1990s interest in this technology was revived by Reneker to spin a wide range of polymers. Electrospun nanofiber webs have been found to serve as near ideal substrates for growing soft tissues as the high surface area and the three-dimensional interconnected pore network resembles the... 

Figure 8.16a shows two piezoelectric signals from the as-electrospun nanofiber web (thick line) and the heat-treated nanofiber web (thin fine) for the active area (i.e., the area of imparting pressure on the sensor) with a diameter of 1.2 cm (diameter of the pressure-imparting probe) and the applied frequency of 5.3 Hz (these are the same throughout the experiment, unless slated othewise). 

The next question then follows. Are the dipoles in the as-electrospun nanofiber web really oriented perpendicular to the nanoweb surface (although we have some idea as described by the FTIR results) If so, is it also possible to verify this... 

The electrospun PVDF and P(VDF-TrFE) fibrous webs have good piezoelectric properties, showing that they have preferred orientation of molecular dipoles. In order to prove this, P(VDF-TrFE) webs were characterized by infrared (IR) spectroscopy and the piezoelectric signal from the electrospun nanofiber web. The result provides the evidence of the preferential orientation of CF2 dipoles in the P(VDF-TrFE) nanofiber web during electrospinning. 

Lee S, Obendorf SK (2007) Use of Electrospun nanofiber web for protective textile materials as barriers to liquid penetration. Text Res J 77 696-702... 

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