For my thesis research, I dissolved PLA and PCL in chloroform: methanol (3:1), PMMA (350.000 MW, 13 wt%) in acetone, and collagen in acetate acid--and then, I mixed them together. The problem is when I tried to electrospinning with this solution, forming fibers always begins with the 'thick' one and then thin and then thick again and so on. Second problem is the fiber synthesis is uncontinuous. I use needle 21 G with electrospinning parameters 13 kV, flow rate 2 ml/h, and distance between collector and needle is 10 cm.
I have a plan for next trial to do these things:
a. Change acetone with ethylacetate (ethylacetate has higher boiling point than acetone)
b. Decrease the concentration.
Here, I attached some pictures and video about my electrospinning problems (as you can see, I circled the 'thick' part)
Is there any suggestions for me on how to make continous fiber synthesis uniformly? Thank you.
Evangelina Tessia pricilla:
Judging from the pictures and the video you attached, I believe the problem could be associated with your solution viscosity and injection rate. Too thin an e-spin solution can cause the discontinuity of e-spin stream as you observed. Injecting too fast might also be a problem.
In my lab, we typically set the solution concentration to be ~16 wt% and an injection rate between 0.01-0.05 mL min-1. Thus, your concentration and injection rate are seemed inappropriate to me. However, I have to admit that my parameters might be inapplicable to your case as we deal with different materials. A rule of thumb is to visually check the continuity of e-spin streams or use glass slides to collect some fibers and view them under an optical microscope to check the fiber morphology. Based on my experience, use of high-boiling-point solvents would worsen your situation.
Article Development of meniscus substitutes using a mixture of bioco...
This article has some information on electrospinning the same combination of polymers.
I think selection of low molecular weight PMMA may solve this problem. Further, compensate for the loss of Chloroform due to vaporization.
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