I want to make electrospinning scaffold with PLA/PCL/PMMA/Collagen with these methods:
1. I use chloroform:methanol 3:1 to dissolve PLA (mW 80.000, 2 wt%), PCL (mW 70.000, 3 wt%), and PMMA mW 350.000, 5 wt%). Each of polymers is stirred for 3 hours and then I mixed together for 3 hours.
2. I use acetic acid 80% to dissolve collagen (8 wt%) and stirred it for 3 hours.
3. I mixed polymers solution with collagen for 3 hours.
4. I dont use any heating system/high temperature at all to dissolve them together.
I use these electrospinning parameters:
1. I use needle electrospinning with 10 cm, 1.5 ml/h, and 20 kV. I have used lower voltage and this problem still occured. I found that the minimum voltage to produce this nanofiber is 10 kV.
2. I did some research and found that this problem is likely to be occured because the voltage is too high. I've tried at minimum voltage (10 kV), but this problem still happened.
2. I place tissue paper at the bottom of needle. I have a little suspicion with the tissue paper. Is there by any chance this tissue paper could affect this problem?
Instead of being deposited on the aluminium foil, the fibers hanging like web between needle and collector, and not many of them could deposited at the aluminium foil.
How to solve this hanging web electrospun fiber problem (early solidification) in my case?
Thank you so much for your help.
Hi Evangelina Tessia pricilla
Your problem seems to come from solution. The average molecular weight of your polymers is 212,000 g/mol; Quite a high value. You did not specify how much your concentration is; weights of chloroform, methanol and acetic acid? The concentration should be low according to your average molecular weight and should be an optimal value with these trials. My advice is to make experiments in the 5-8% concentration range.
If it fails, you can try lowering the PMMA by weight. Which rates will vary depending on your purpose. The concentration should be determined according to the average molecular weight in each ratio.
PLA/PCL/PMMA > 4/4/2 - 5/3/2 - 4/3/3 - 3/4/3 - 5/4/1
If you increase the TCD distance, you can achieve a more comfortable operation, and the feed rate looks higher. If you work with microliters/min while working with a single needle, solution flow from the needle tip is reduced.
Good work.
Hello, Behzat YILDIRIM . First of all, thank you so much for your answer. So, by that means, you give me some points which are:
1. Reduce PMMA in my solution by the weight (currently, I use 0.5 gram/10 ml (choroform:methanol 3:1). so maybe I'll try to reduce it around 0.2 - 0.3 gram/10 ml solvent)
2. Increase the distance between needle tip and collector.
3. Lower the feed rate (I plan to make it low until 0.5 ml/h or 7 - 8.5 microliters/min)
Is my point right?
Thank you so much.
Hi Evangelina Tessia pricilla,
The conclusions are correct but there is a more important detail. Your concentration is 1g/10 mL and your average molecular weight is 212,000 g/mol. Working at a lower concentration may also be an inference. Polymers can be kept constant in weight and the amount of solvent can be increased. I'm not sure how much, but 14 mL can be tried. In fact, the same solution in reducing the amount of PMMA, your average molecular weight will be reduced. Your goal here is priority, so you have to decide which solution to start with.
I also want to make another point. If the Collagen you are using is a material that contains water, it can trigger this.
You can also follow this discussion, it can help.
https://www.researchgate.net/post/PAN_DMSO_needleless_electrospinning_deposition_problem
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