Dear Sarah Sahota, there are many others options related to the electrospinning process and electrospinning solution properties. For the process, long spinning time and high diameter needle lead to thicker layers. Also solution conductivity may be another parameter to play on for thicker layers in addition to those you mentionned. Please check the following documents. My Regards

https://doi.org/10.1016/j.arabjc.2015.11.015

https://www.researchgate.net/post/How-do-I-control-web-thickness-in-electro-spinning

https://www.researchgate.net/publication/278712823_Effects_of_Working_Parameters_on_Electrospinning

https://iopscience.iop.org/article/10.1088/2053-1591/ab58e0

Dear Sarah Sahota, there are many others options related to the electrospinning process and electrospinning solution properties. For the process, long spinning time and high diameter needle lead to thicker layers. Also solution conductivity may be another parameter to play on for thicker layers in addition to those you mentionned. Please check the following documents. My Regards

https://doi.org/10.1016/j.arabjc.2015.11.015

https://www.researchgate.net/post/How-do-I-control-web-thickness-in-electro-spinning

https://www.researchgate.net/publication/278712823_Effects_of_Working_Parameters_on_Electrospinning

https://iopscience.iop.org/article/10.1088/2053-1591/ab58e0

Thank you

Thank you

Hi;

The inner diameter of the needle or nozzle is also a necessary parameter to be adjusted before starting the electrospinning process. Increasing the diameter of the nozzle makes it possible to produce large filaments with high average diameters. Please see the link below:

https://www.academia.edu/26647566/EFFECT_OF_NEEDLE_DIAMETER_ON_DIAMETER_OF_ELECTROPSUN_SILK_FIBROIN_NANOFIBERS

With my best regards

Sarah Sahota

You have few options available to you. Dip coating tends to produce thicker films than spinning. Increase the concentration of the polymer, reduce the spin speed.

However, I think your problem is more fundamental than this. I don't think you can avoid yellowing and opacity as both the film is too thick and the plasma etching is altering the surface. One suggestion would be to spin your first layer on and spin until just dryness (you can actually see this happening by the interference films), do not remove the plate from the chuck (I used Headway spinners in the semiconductor business), then immediately spin on a second layer etc. 'Like prefers like' and this may be able to produce a second layer without a strong boundary. I would not be using plasma etching after each step - you're modifying the process/surface.

My question would be 'why do you need a 120 micron thick film'? I'd be thinking 'How can I do what I want to do (and we do not know what that is in your case and the end application dictates everything prior) with a 10 micron or a 1 micron film?...

So, my objective would actually be to reduce that thickness. I would be questioning your first sentence 'I need to spin a 120um thick film' with the answer 'Why? Why is it 'need' and not 'desire'?.