Good afternoon, I am trying to prepare solution for electrospinning with PEO,H2O and NaCl.
The MW of PEO is 1,000,000.
At the beginning I add 1,25% NaCl to 95,75% water under 25°C stirring, then I add 3% PEO and stir it under 80-90°C till it will be completely dissolved (+ - 4 hours). Instead of fbers I get solution droplets.
If anybody can say me where my mistake is ?
Also I tried - PEO 3%, H2O 95,25% and NaCl 1,75% /// PEO 3%,H2O 94,5% and NaCl 2,50%. , and PEO with concentration 1%,1.4%,1.63%,1.75%,2%,3.7%,4% - everything are failed.
Maybe someone can also say me what the parameter for PEO 1,000,000 will be the best for electrospinning?
The quality of electrospun poly(ethylene oxide) (PEO) nanofibrous mats are subject to a variety of input parameters.
1.The polymer (molecular weight, molecular weight distribution, topology of macromolecules),
2. Solvent (surface tension, solubility parameters, relative permittivity),
3. Solution (viscosity, concentration, specific conductivity),
4. And process parameters (electric field strength, tip-to-collector distance, temperature, humidity).
PEO contains strong polar groups to obtain strong interactions with an electric field. This condition is expressed by a high value of the dielectric constant.
In your case, Salt NaCl added to PEO solution decreased the spinning performance of fibres while creating thin nanofibres, as explained by the leaky dielectric model.
Salt increases the conductivity of polymer solutions. Increase in conductivity changes the characteristic of the polymer solution from a semiconductor to a conductor. Therefore, the solution loses the characteristic of a leaky model, which leads to the loss of ability to create Taylor cones. According to Bahattacharjee and Rutledge , “a leaky dielectric differs from a perfect conductor or a dielectric material in that free charges accumulate on the surface of the material in the presence of an external electric field and modify the local field.
PEO at 400 kDa, with its high polarity and high entanglement number (strength of jets), shows high spinning performance. This performance is reduced by the increase in conductivity [1].
Reference
1. Influence of Salts on Electrospinning of Aqueous and Nonaqueous Polymer Solutions.
By Fatma Yaicinkaya et.al. 2015.
Also, Please see this reference, which could help you in your experiences.
2. Enhancing properties and water resistance of PEO-based electrospun nanofibrous membranes by photo-crosslinking, Parninan Kianfar et.al. 2021.
3.Characterization of Poly(Ethylene Oxide) Nanofibers—Mutual Relations between Mean Diameter of Electrospun Nanofibers and Solution Characteristics.
Petr Filip * and Petra Peer, 2019.
Thank you
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