Electro-spinning process

Casper, C.L., Stephens, J.S., Tassi, N.G., Chase, D.B. and Rabolt, J.F. 2004. Controlling surface morphology of electrospun polystyrene fibers Effect of humidity and molecular weight in the electro spinning process. Macromolecules 37 573-578. 

Chronakis, I S. Novel nanocomposites and nanoceramics based on polymer nanofibers using electro spinning process—A review. J. Mater. Proc. Tech., 2005,167,283-293. 

Different parameters have been identified to affect the electro-spinning process and consequently, the morphology and the dimension of the fabricated fibres. An example of solvent effect on the final PLLA fibre dimension and morphology is shown in Fig. 3.6. The effect of different solvents on the morphology of PCL fibres was also investigated and previously reported in literature (Qin and Wu, 2012). 

Montini-Ballarin F, Caracciolo PC, Blotta E, Ballarin VL, Abraham GA. Optimization of poly(L-lactic acid)/segmented polyurethane electro spinning process for the production of bilayered small-diameter nanofibrous tubular structures. Mater Sci Eng C 2014 42 489-99. 

Figure 19.3 A list of electro spinning factors including properties of the polymer solution and parameters of the electro spinning process.

Rogina, A., 2014. Electro spinning process versatile preparation method for biodegradable and natural polymers and biocomposite systems apphed in tissue engineering and drug delivery. Applied Surface Science 296, 221-230. 

The versatility of the electro-spinning process allows for controlling not only the fiber size, morphology and macroscopic assembly, but also, and more importantly, tailoring of the optical properties of the fiber. Electro-spinning has turned ont to be a better choice because of its simplicity, economy, scaling capability [112] and control over the nanomembranes morphology [113]. 

Yoon, S., Anand Prabu, A., Ramasundaram, S., and Kim, K.J. (2008) PVDF nanoweb touch sensors prepared using electro-spinning process for smart apparels applications. Adv. Sci. Technol., 60, 52-57. 

A comparison of the various methods for fabricating nanofibres explains why electro-spinning has dominated our research interests as a process it is convenient to perform, can be applied in industrial mass production, and allows proper control of morphology and properties of the products more importantly, it is the only approach capable of producing filaments from a large variety of natural and synthetic polymers. For this reason, electrospim nanofibres are the focus of the rest of this chapter. 

Using appropriate anhydrous processing techniques, which prevent the hydrolysis of the active ester end groups, then allows for the manufacture of biomimetic scaffolds for tissue engineering.Further commonly used processing techniques for the overall class of poly(a-hydroxy esters) include electro-spinning for the manufacture of fibers and emulsion/solvent... 

Figure 3.2 Illustration of sol-gel process of preparing nanocoating via three different coating techniques dip coating, spin coating, and electro spinning.

Thermoplastic fibers are typically fabricated via a melt spinning process wherein the melt is extruded through the many holes in a spinneret and cooled to harden. Other fiber materials can be dissolved in a solvent and then exhuded, with the sohd fibers precipitating from solution either due to a chemical reaction in a liquid bath or due to solvent evaporation in a gas. The latter method, dry spinning, is closest to the focus of this section— electro spinning of nanoflbers. 

In the present paper a kinetic theory of crystal nucleation is considered for the polymers subjected to time-dependent deformation rates, with transient effects of the chain relaxation. The considerations provide a theory useful in modelling fast polymer processing with stress-induced crystallization, like high-speed melt spinning, melt blowing, electro-spinning, etc. 

The preparation of MFCs is quite different from that of the conventional composites, insofar as the reinforcing micro- or nanofibrils are created in situ during processing, as is the relaxed, isotropic thermoplastic matrix. The MFC technology can, therefore, be contrasted with the electro-spinning methods used to produce nano-sized materials mainly in the form of nonwoven fibers with colloidal length scales, i.e., diameters mostly of tens to hundreds of nanometers [57]. 

Kim GH, Son JG, Park SA, Kim WD. Hybrid process for fabricating 3D hierarchical scaffolds combining rapid prototyping and electro spinning. Macromol Rapid Commun 2008 29 1577-1581. 

Eleikkila, P Harlin A Electro spinning of polyacrylonitrile (PAN) solution effect of conductive additive and filler on the process. Express Polymer Letters 2009, 3, 437-445. 

Rose, M. Bohringer, B. JoUy, M. Fischer, R. Kaskel, S. MOF processing by electro-spinning for functional textiles. Advanced Engineering Materials, 2011, 13,356-360. 

Electro spinning is a process used by the nanofiltration process, in which fibers are stretched and elongated down to a diameter of about 10 nm. The modified nanofibers that are produced are particularly useful in the filtration process as an ultra-concentrated filter with a very large surface area. Studies have found that electro spun nanofibers can capture metallic ions and are continually effective through refiltration. 

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