Solvents electrospinning

Non-woven fiber mafs composed from PPE and PS blends have been prepared by electrospinning of PPE/PS solutions in a mixture of chloroform and hex-alluoroisopropanol [55]. The materials showed a better electrospinnability which resulted in thinner fibers with diameters of200 nm-1.3 xm than fibers obtained from the pure components. This arises from a proper balance of the electrical conductivity and interaction with the electrospinning solvent. 

Electrospinning (solvent) Long, continuous nanofibres Fibre diameters are quite uniform Wide range of fibre diameters possible Needleless systems have high throughput Small pore size Uniform fibres with diameters <50 nm difficult Needle systems, low productivity Jet instability Solvent recovery issues Low mechanical properties... 

Kwon and coworkers prepared a series of nano- to microstmctured biodegradable PCLA porous fabrics by electrospinning. The nanoscale-fiber porous fabrics were electrospun with PCLA (1 1 mole ratio, approximately 0.3-1.2 mm in diameter) using l,l,l,3,3,3-hexafluoro-2-propanol as a solvent. 

The surface tension seems more likely to be a function of solvent compositions, but is negligibly dependent on the solution concentration. Different solvents may contribute different surface tensions. However, not necessarily a lower surface tension of a solvent will always be more suitable for electrospinning. Generally, surface tension determines the upper and lower boundaries of electrospinning window if all other variables are held constant. The formation of droplets, bead and fibers can be driven by the surface tension of solution and lower surface tension of the spinning solution helps electrospinning to occur at lower electric field [57],... 

Dong B et al (2009) Electrospinning of collagen nanofiber scaffolds from benign solvents. Macromol Rapid Commun 30(7) 539-542... 

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. 

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