Electrospun solution viscosity

Similarly Shalumon et al. also fabricated electrospun porous poly(lactic acid) (PLA) multiscale scaffolds and evaluated their physicochemical and biological properties in detail [53]. These multiscale scaffolds were developed through a bimodal fiber fabrication system. The three main solution properties, solution viscosity, conductivity, and surface tension, were determined to be the governing... 

The physical characteristics of electrospun nanofibres, such as fibre diameter, depend on various parameters which are divided into three main categories (a) solution properties (solution viscosity, solution concentration, polymer molecular weight, and surface tension) (b) processing conditions (applied voltage, volume flow rate, spinning distance, and needle diameter) and (c) ambient conditions (temperature. 

Figure 8.2 Correlation of solution viscosity and morphological structures of electrospun PLA/HMW PCL (blend ratio 1/1) fibers using chloroform/methanol [60]. The scale bars in SEM micrographs represent 10 pm.

Nezarati RM, Eifert MB, Cosgriff-Hemandez E. Effects of humidity and solution viscosity on electrospun fiber morphology. Tissue Eng Part C Methods 2013 19 810-9. 

Ffe. 7 a SEM midographs showing the inverse relationship between the polymer solution viscosity used during electrospinning and the amount of beaded regions detected in the corresponding electrospun nanofibers, b, c PCL electrospun nanofibers made from 9 to 5 % PCL solutions, respectively. Adopted from Huang et al. (2003) and Pham et al. (2006)... 

In PLA solutions 10 wt.% was dissolved in 70 30 wt.% DCM DMF mixtures, it was found that the optimum ratio used for electrospun fibers [11,12]. Addition of CA into PLA solutions were to prepare by dissolving CA in the amount of 1 and 3 % based on the weight of total polymer. PLA and PLA/CA solutions were used as the shell fluid. A GS-loaded PEG was prepared by dissolving PEG 10 g in GS solution 3 ml used as the core fluid. Each solution and its content can be tabulated and its nomenclature as shown in Table 2. Solution viscosity was carried out for all the solutions by use of a viscometer (Brookfield Model LV Co., USA). 

Figure 4.3 shows the image of a nonwoven mat of electrospun N6 fibers on a foil of aluminum. The SEM micrographs in Figs 4.4 and 4.5 show some beads in electrospun N6 fibers. The results showed that with increasing applied voltage formation of beads decreased. The beads can be removed by controlling solution viscosities and electrical conductivities of the polymer solution. ... 

Relationship between polymer concentration, solution viscosity and diameter of electrospun polyacrylonitrile (PAN) fibres. 

The formation of beaded fibres has been attributed to a low solution viscosity (Fong et al., 1999, Lee et al., 2003). Increasing the polymer concentration, which results in an increase in the solution viscosity, has been the conventional approach to prevent the formation of the beads. However, increasing the solution viscosity is not always effective. With some polymers, polystyrene for instance, even a high concentration of polymer solution does not guarantee bead-free electrospun fibres. 

Ceramic nanofibers also can be synthesized by the calcination of electrospun precursor nanofibers. Electrospun ceramic nanofibers were first reported by Dai and his coworker in 2002. Since then, more than twenty ceramic systems (e.g., SiO, Al Oj, and ZrOj) have been fabricated as nanofibers. Ceramic fibers can be either amorphous or polycrystalline, depending on the material type and processing conditions. Figure 7.6 shows ZrO nanofibers, which were synthesized from zirconium oxychloride (ZrOClj) precursor. During electrospiiming, polyvinyl alcohol (PVA) was added to achieve desirable solution viscosity and improve the electrospinnability. The electrospun ZrOCl /PVA nanofibers were heat-treated to form ZrOj nanofibers, during which ZrOCl was converted to ZrOCl while PVA was pyrolyzed. 

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