Parameters Affecting Electrospinning

Filtration system applications include heating, ventilation, and air conditioning (HVAC), high-efficiency particulate arrestance (HEPA), and ultra-low penetration air (ULPA) filters as well as filters for automotive, beverage, pharmacy, and medical applications. Filter media for new air and liquid filtration applications, such as vacuum cleaners, are also applications of filtration systems.  

Applications in energy area include Li ion batteries, photovoltaic cells, membrane fuel cells, and dye-sensitized solar cells. Other applications are micropower to operate personal electronic devices via piezoelectric nanofibers woven into clothing, carrier materials for various catalysts, and photocatalytic air/water purification.  

In the electrospinning process, the following three parameter classes have relative effects on the resulting fiber properties  

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Jalili R et al (2006) Fundamental parameters affecting electrospinning of PAN nanoflbers as uniaxially aligned libers. J Appl Polym Sci 101 (6) 4350 4357... 

Jalili, R., Morshed, M., Hosseini Ravandi, S. (2006). Fundamental Parameters Affecting Electrospinning of PAN Nanofibers as Uniaxially Aligned Fibers, j j li 2 merScien 101, 4350 357. 

Jalili R, Morshed M, Abdolkarim S, and Ravandi H (2006) Fimdamental parameters affecting electrospinning of PAN nanofibers as uniaxially aligned fibers, J Appl Polym Sci 101 4350-4357. 

Okutan, N., Terzi, P., Altay, F., 2014. Affecting parameters on electrospinning process and characterization of elecfrospun gelatin nanofihers. Food Hydrocolloids 39 (August), 19—26. Available from http //dx.doi.Org/10.1016/j.foodhyd.2013.12.022. 

Solvent volatility is an important factor in electrospinning. Since electrospinning requires a quick evaporation rate and phase separation, vapor pressure of the solvent affects the dr5dng time and evaporation rate. Other parameters affecting evaporation rate are boiling point, specific heat, enthalpy and heat of vaporization, rate of heat supply, interaction between solvent molecules, surface tension of the liquid, and air movement above the liquid surface. 

FIGURE 8.4 Classifications of parameters affect PAN solution electrospinning. 

The aim is generally to produce fibers with a well-determined fiber diameter which has a small standard deviation. Fibers should also be without defects [43], This can be obtained by adjusting the solution, process, and environmental parameters which affect electrospinning. 

The optimal precursor material consists of fibers which are defect-free and continuous for industrial purposes. The solution and electrospinning process should be optimized considering the parameters affecting fiber quality, such as concentration, applied voltage, etc. [160,161]. 

The fiber diameter of an electrospun scaffold is closely related to the scaffold properties and the biological response. It is influenced by the properties of the polymer solution and the parameters of the electrospinning process (Figure 19.3). Although the electrospinning device setup is simple, it is important that these parameters be comprehensively considered to achieve an optimal scaffold. The major parameters affecting the fiber diameter and the sample morphology are described as below. 

Besides the above-noted parameters, there exist some other factors affecting electrospinning, such as the surrounding environment (e.g., humidity [20]). However, all these parameters interact and cannot be individually considered to achieve a perfect fibrous scaffold. All parameters must be comprehensively studied and optimized for electrospinning control. 

Two classes of variables that affect electrospinning can be identified from the literature the materials variables relating to polymer and solvent characteristics and the process variables pertaining to either the choice of equipment (e.g., the collector plate material or the spinning environment) or the operating parameters. For convenience of description these are categorized as shown in Scheme 4.1 as the materials variables (A, B, and C) and process variables (D, E, F, and G). However, because these are interrelated, a small... 

Despite the fact that the electrospinning technique is relatively easy to use, there are a number of process parameters that can greatly affect fiber formation and structure. Listed in order of relative impact to the electrospinning process, the most important parameters are applied voltage, polymer flow rate, and capillary-collector distance. All three parameters can influence the formation of nanofibers with bead-like defects. 

Nanoscaled PCL and PCL/gelatin fibrous scaffolds with immobilized epidermal growth factor (EGF) were prepared for the purpose of wound-healing treatments [80]. The tissue scaffolds were fabricated by electrospinning and the parameters that affect the electrospinning process were optimized. In this study, the fiber diameters were 488 114 nm and 663 107 nm for PCL and PCL/gelatin scaffolds, respectively, and the porosities were calculated as 79% for PCL and 68% for... 

Electrospinning process produces very fine fibers and this is one of the very few methods from which fibers of sub-micron size can be produced. So it becomes immensely important to understand the behavior of fiber diameter and fiber diameter distribution in the electrospun web as impacted by the independent variables (processing parameters). Understanding how fiber diameter and diameter distribution are affected by the processing parameters is essential to produce webs with desired fiber diameter and distribution. 

The following parameters and processing variables affect the electrospinning process (i) system parameters such as molecular weight, molecular weight distribution and architecture (branched, linear, etc.) of the polymer, and polymer solution properties (viscosity, conductivity, dielectric constant, and surface tension, charge carried by the spinning jet) and (ii) process parameters such as electric potential, flow rate and concentration, distance between the capillary and collection screen, ambient parameters... 

The morphology and the diameter of the electrospun nano Hers can be affected by many electrospinning parameters including solution properties (the concentration, liqnid viscosity, surface tension, and dielectric properties of the polymer solution), processing conditions (apphed voltage, volume Cbw rate, tip to collector distance, and the strength of the apphed electric Hid), and ambient conditions (temperature, atmospheric pressure and humidity) [17-20]. 

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