Electrospinning electrospun nanofibres

FIGURE 55.5 Schematic of the dual spinneret electrospinning apparatus. (Reprinted from Int. J. Pharm., 364(1), Thakur, R.A., Florek, C.A., Kohn, J., and Michniak, B.B., Electrospun nanofibrous polymeric scaffold with targeted drug release profiles for potential application as wound dressing, 87-93. Copyright 2008, with... 

There are some commercially available electrospinning processes, such as the Nanospider electrospun nanofibres, which can provide thin coatings on traditional filtration substrates and enhance the filtration performance of these materials many fold. This technology can yield nanofibres with a narrow diameter distribution and distinct diameter size that can be used to optimise the filtration behaviour of the filter substrates for many applications, where particle retention efficiency is a critical requirement. These suhmicron fibres can significantly improve the air filtration efficiency of a variety of media and filters. The submicron fibres provide improved filter efficiency in the interception and inertial impaction regimes. ... 

Preliminary studies were performed to find the optimum conditions for electrospinning PVA solutions. As the polymer concentration increased, a mixture of beads and fibres was formed. Therefore, a PVA concentration of 10% was used for preparation of electrospun nanofibres. A series of mats were prepared from the 10% PVA solution in a mixture containing various amounts of ferric chloride or ammonium persulfate as oxidant at the 15 kV constant electric field. SEM photomicrographs of electrospun PVA nanofibres from a 10% solution showed the presence of uniform nanofibres with diameters ranging from 150 to 400 nm, with an average diameter of 350 nm. 

The effects of processing parameters on the morphology of electrospun nanofibres are summarised in a processing map (Figure 4.14). A suitable combination of the processing parameters should be attained to electrospin polymers into nanofibres... 

This book presents some fascinating phenomena associated with the remarkable features of nanofibres in electrospinning processes and new progress in applications of electrospun nanofibres. 

As reported in other chapters in this volume, PLA is one of the most used materials for biomedical applications due to biocompatibility and biodegradability, but hydrophobic properties require the encapsulation of water-soluble agents to avoid decomposition and failure of the polymer as a drug-carrier substrate. One of the advantages of coaxial electrospinning is that solid or liquid drugs can be incorporated into electrospun nanofibres and it is possible to encapsulate drugs into a structural shell. 

He J-H, Liu Y, Mo L-F, Wan Y-Q and Xu L (2008) Bubble electrospinning biomimic fabrication of electrospun nanofibres with high throughput, in Electrospun nanofibres and their applications, iSmithers, Shawbury, UK, pp. 131-156. 

Li D, Xia Y (2004) Direct fabrication of composite and ceramic hollow nanofibers by electrospinning. Nano Lett 4(5) 933-938. doi 10.1021/nl049590f Li W-J, Laurencin CT, Caterson EJ, Tuan RS, Ko FK (2002) Electrospun nanofibrous structure a noyel scaffold for tissue engineering. J Biomed Mater Res, 60(4) 613-21. http //www.ncbi. nlm.nih.gov/pubmed/11948520... 

In the past 10 years, electrospun nanofibrous membranes have been spotlighted as an effective filter media to capture fine particles. In addition to the basic studies of electrospinning process to better understand the membrane construction process, researchers from all over the world focus on the study of the relationships between the structure characteristics of electrospun nanofibrous membranes (fiber diameter, pore size, porosity, surface area, etc.) and filtration performances (filtration efficiency, pressure, air permeability, etc.). In this chapter, recent advances in fabricating nanofibrous filter media via electrospinning process have been reviewed. In particular, filtration performances and relevant mechanical properties are discussed in detail. It is interesting that the electrospun nanofibrous membranes have been able to outperform conventional nonwoven membranes fabricated essentially by using the meltblown or spunbonded process. 

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