I'm trying to make PCL aligned fibers.
I've tried to adjust voltage, flow rate and needle-collector distance.
Parameters :
- 15% PCL in acetone (weight/volume)
- Needle-collector distance: 5 to 20 cm
- Voltage: 5 to 20 kV
- Flow rate : 1 to 10 mL/h
- Rotating speed: 500 to 2400 rpm
I manage to get fibers (at the lowest rotation speed) but they are not aligned.
I've tried to reduce flow rate, but still the rotation speed is too low and thus fibers are not aligned enough.
Above 500 rpm I can't manage to get a Taylor cone, and the droplet/jet constantly moves and solidifies.
I've read publications using similar parameters to mine and getting aligned fibers, what am I missing ?
Hi Thomas,
Probably use a more conductive solvent like HFIP? You could also wrap around the drum with a relatively more conductive material like an aluminium foil, just to improve the electric field between the tip and the collector. Hope this helps.
Dear all, I think you should :
- reduce the concentration
- if possible change the solvant to a better one
- use high voltage
- use higher rpm and play only on the interdistance.
My Regards
Abdelkader BOUAZIZ Ashang Luwang Laiva
Thank you very much to both of you for your help.
Changing the solvent is not an option, but I will try to wrap the drum with aluminium to see if it makes a difference.
Otherwise I've managed to get fibers at 2000 rpm using lower concentration, and playing around with voltage. They are not perfect yet but it's getting better. Thanks again!
Hi Thomas
I would recommend to stabilize your Taylor cone and minimize wind from the rotating drum. Please see post linked below for more info.
https://www.researchgate.net/post/Why_did_not_I_obtain_fibers_when_electropun_PLGA_dissolved_in_DCM
Success!
Marc
The key parameter should be the rotating speed of drum collector. If you still cannot get good results, perhaps the problem is air humidity. If relative humidity is above 50%, the charge of the nanofibers disappears soon and there is no electric field pushing the nanofibers to reach the collector.
Marc Simonet, Thank you for your insight, I agree with you, the rotating drum definitely creates some wind which upset the Taylor cone stabilization. I've tried to mitigate its effect by increasing the needle-collector distance and using higher voltage to overcome this phenomenon.
At this point, I get oriented fibers but not perfectly aligned fibers.
The only effective solution i've found to decrease wind is to reduce the rotating speed... Do you have any leads to minimize wind ?
Sergio Mollá, It's true, I've noticed that relative humidity does have an impact on the electrospinning process, but in this case it works fine at low rotating speed with the same humidity.
Thank you for your help anyway.
Thomas Haroche,
ACE is considered a highly volatile solvent, therefore, the bending instability of the jet will be too high resulting in not only collecting few fibers on the collector but also not perfectly aligned fibers. Consequently, decreasing the bending instability to a sufficient level will be the best choice. I suggest decreasing the needle-collector distance, increasing the relative humidity, and not using a very high rotation speed of the collector.
Best Regards.
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