Electrospinning solution conductivity

Fiber jet speed and material elasticity are two of the most important parameters involved in the jet-mandrel interaction and each of these properties are influenced by multiple electrospinning parameters, such as solution conductivity, viscosity, voltage, and feed rate. In addition, material properties cannot be accurately predicted without knowing the exact degree of solvent evaporation at the point when fibers are taken up by the collector. 

In addition to the process parameters, a number of system parameters play an important role in fiber formation and the obtained structure. System parameters include molecular weight, molecular weight distribution, polymer architecture, and solution properties. Solution properties play a particularly important role. In relation to their impact on the electrospinning process, these factors can be ranked as follows polymer concentration, solvent volatility, and solution conductivity. 

The relatively low molecular weight of conductive pol miers, decrease in specific viscosity of composites resulted a small nanofiber diameters. Interaction of PPy with matrix creates a decrease in viscosity, and that causes the smaller diameter of nanofibers. Moreover, electrospinning solutions of nanofibers with small average diameters have exhibited higher conductivity. 

In addition, one-phase smfactant-assisted chemical method has been utilized to synthesize PANI nanofiber, which was doped with CSA and 2-acrylamido-2-methyl-l-propanesulfonic acid, in large quantities [291]. A chemical oxidative polymerization of aniline has been carried out using ammonium peroxydisulfate as an oxidizing agent in the presence of nonionic surfactant. A precipitate of doped emeraldine salt is composed of PANI nanofiber, which has the diameter of 30-50 nm and exhibits the conductivity of 1 -5 S cm at RT. Another piece of research has been done through chemical oxidation polymerization of aniline in a surfactant gel, which was formed by a mixture of hexadecyltrimethylammonium chloride, acetic acid, anihne, and water at - 7 °C [292]. The dendritic PANI nanofiber has the diameter of 60-90 nm and the length of 1 -2 jim. Extended works have been performed by the electrospinning method [293]. It should be taken into account that PANI-CSA fiber shape could be influenced by the synthetic variables such as solvent, surface tension, viscosity, and solution conductivity. 

The fiber morphology is controlled by the experimental parameters and is dependent upon solution conductivity, concentration, viscosity, polymer molecular weight, applied voltage, etc. [34,106] much work has been done on the effect of parameters on the electrospinning process and morphology of fibers. 

The vapor phase chemical deposition of PPy on the surface of the electrospun PVA nanofibers was successfully performed. Morphology of the nanofibers and successful deposition of the PPy onto the nanofibers is governed by the oxidant type and its concentration in the electrospinning solution. At the best studied condition, a layer of PPy with the thickness of 1,000 nm is formed onto the PVA nanofibers surface using ammonium persulfate as oxidant. In contrast, surface coating was not observed in the case of FeClj as oxidant. The electrical conductivity of the coated nanofiber mats depends on the coating conditions and reaches to 10 S/cm. Large surface area of the sensor material with the electrochemical activity is one of the most important properties for sensor application. Since, it is obvious that the surface area of PPy coated non-... 

The electrospinning process fundamentally requires the transfer of electric charge from the electrode to the spinning droplet at the terminus of the tip. A minimal electrical conductivity in the solution is therefore essential for electrospinning solutions of zero conductivity cannot be electrospun. Solvents commonly used in electrospinning have conductivities that are... 

Polymer/surfactant interaction in Lin et al. (2004) electrospinning of nanofibers studied. Cationic surfactants additives reported to improve the solution conductivity, but with no effect on the viscosity. 

The solvent selected for PMMA and GO was a 2 1 mixmre of AfA -dimethylforma-mide (DMF) and THF. Mixture analysis was conducted and validated with the experimentally observed nanofiber morphology and dispersion to determine the optimum level for the three constituents of the electrospinning solution, namely, PMMA, GO, and DMF + THF. 

Angammana, C.J., Jayaram, S.H., 2011. Analysis of the effects of solution conductivity on electrospinning process and fiber morphology. IEEE Transactions on Industry Applications 47, 1109-1117. 

It is well known that many parameters, such as viscosity, elasticity, conductivity, surface tension and distance between tip and collection screen, can influence the transformation of polymer solutions into nanofibers through electrospinning. Solution viscosity is one of the most important factors. Since both polymers have significantly different molecular weights, four different solutions of N6,6 with various concentrations were prepared. We used a mixed solvent consisting of formic acid and chloroform with the ratio of 75/25 (v/v). Table 4.1 shows the solution viscosities for each concentration of low and high molecular weight N6,6. 

The polydisperse solutions were prepared by dissolving the appropriate amounts of polystyrene in tetrahydrofuran (Sigma-Aldrich). Electrospinning was conducted on these solutions for at least 6 different concentrations. A monodisperse polymer solution was... 

Electrospinning was conducted with these solutions. The SEM photographs in Figure 4 show the structure obtained at various concentrations for samples with... 

---