Molecular weight electrospinning

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 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... 

Gupta, P., C. Elkins, T.E. Long, and G.L. Wilkes. Electrospinning of linear homopolymers of poly (methyl methacrylate) exploring relationships between fiber formation, viscosity, molecular weight and concentration in a good solvent. Polymer 46(13) (2005) 4799 810. 

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. 

This siloxane-substituted polyCp-xylylene) exhibits an enhanced solubility. Therefore, the characterization with common techniques is possible, as well as processing electrospinning to get nanofibers. High molecular weights at moderate polydispersities were established by Gel permeation Chromatography (GPC) characterization which is unusual in the case of a vapor phase deposition polymerization technique. 

The parameters involved in the electrospinning processes that affect the nanofiber geometry and structure can be divided into two groups (i) System parameters such as polymer molecular weight, molecular weight distribution, polymer architecture (branched, linear), concentration of the polymer solution and its properties, including viscosity, electrical conductivity, and surface tension and (ii) Process parameters such as applied electric voltage, polymer flow rate, distance between the needle tip and the collector, ambient parameters such as temperature, humidity, and air velocity in the chamber, and motion of the collector (Frenot and Chronakis 2003). 

Koski, A., Yim, K. and Shivkumar, S. 2004. Effect of molecular weight on fibrous PVA produced by electrospinning. Mater. Lett. 58 493 97. 

Intrinsic properties of polyester, such as its molecular weight and parameters of the polymeric solution, such as concentration, viscosity, and conductivity have significant influence on the electrospinning process and the characteristics of the formed fibers [8]. The electrospinning method requires a minimum concentration of polymers for the formation of fibers. The polymer solution must have... 

Dargaville, B.L., Vaquette, C, Rasoul, F., Cooper-White, J.J., Campbell, J.H., and Whittaker, A.K. (2013) Electrospinning and crosslinking of low-molecular-weight poly(trimethylene carbonate-co-(L)-lactide) as an elastomeric scaffold for vascular engineering, Acta Biomater., 9 (6), 6885-6897,... 

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