I have polyethyleneimene, it is in a 50% aq sol form. I have been trying to Electrospin but I dont seem to be getting any fibers, I've tried to add more water to it so as to decrease the viscosity but to no avail. I just keep getting drops. Conditions used were 15-25kV, 10-15cm distance, 1ml/hr flow rate
Can anyone with experience with PEI suggest any other solvent that is sure to work? Please know that the polymer comes in an 50% aq sol. form from the supplier.
PEI is also soluble in Ethanol/Methanol and Chlorofrom.
Do you know the molecular weight of your PEI? The Mw is probably not high enough and hence the solution does not have enough chain entanglements for a stable spinning.
Does your research allow you to mix in a polymer with a higher molecular weight? This gives your solution enough viscosity and chain entanglements for spinning.
Most people I know use PEO in these situations, but you could also adapt following publication with
PCL: doi:10.1016/j.msec.2009.01.023
As I see you use branched PEI (brPEI). Check for article in attachment. Successful electrospinning was performed wtih linear PEI (l-PEI), additionally cross-linked. Preparation is included in publication. l-PEI is commercially available but costly (PolyScience, for instance)
If you prefer to start from brPEI, you can use data from publication, but keeping in mind that:
1) In contrary to solid l-PEI, pure brPEI is very viscous liquid
2) brPEI is active chemical adsorbent of CO2 and hygroscopic - so inert and dry atmosphere is needed. 3) brPEI is much more cytotoxic of l-PEI because of presence -NH2 , but it can be reduced by selective chemical modification.
If you want to spin from water ( that is the worse solvent for electrospinning that exists) consider to co-extrude it in a blend with another fibre forming water soluble polymer.
When one choose solvent for electrospinning,the primary selection parameter is dielectric constant. From my understanding, people would want to use water there is no option of other solvent or they want the polymer to be only processed via water.
From what i understand you have an option of chloroform. Do try using that, i have personally electrospun with chloroform without any issue.
You have to play with the concentration if it is received from supplier. It could be not viscous, in this case you have to add powder.
Try to change spinning temperature. You need to find a balance in between Viscousity, surface tension, repulsion forces by playing with temperature, electrode distance, voltage amplitude, feeding rate and concentration.
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