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Author: Subject: Electrospinning experiments
wg48temp9
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[*] posted on 30-12-2018 at 04:36
Electrospinning experiments


I did a crude experiment to try some electrospinning. I used a -5kV supply connected a hypodermic needle using a glycerol solution (e-liquid). I was unable observe any spray but the liquid flowed back along the needle and formed drops. I decided the grounded counter electrode was needed so I positioned one by hand. Ouch I got zapped, only 50uA plus whatever the output C current was.

Unexpectedly the sharp needle allows a spark to jump about 20mm while between blunt wires it’s only a few mm. I had no idea a really sharp point could extend the sparking distance so much. On closer examination of the needle there was a brush discharge from needle and a mild wind smelling of ozone.

My electrospinning experiments continue more carefully LOL.
I wounder if I can electrospin candy floss at 50kV or perhaps ceramic fiber.




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[*] posted on 30-12-2018 at 20:39


Improvments in the set up

So I lapped the tip of the hypodermic needle flat and square and fixed the syringe in a clamp. I then placed a large washer in front of the needle with needles axis thru the middle of the hole in washer and about 10mm from the needle tip a few mm greater than the sparking distance.

With a drop of liquid at the needle tip I turned on the HT. The drop disappeared and a small wet patch appeared on the paper placed 20mm from the far side of the washer. Success the liquid was propelled through washer's hole and hit the paper. I then tried gently depressing syringe plunger force more liquid from the needle. No visible drop formed on the needle tip as it was immediately propelled in the direction of the washer. Some hit the washer and some hit the paper in various spots some 30deg of axis. The paper was mounted on plastic i suspect the paper and plastic charged up deflecting the liquid stream. The blunt needle reduced the brush discharge (still visible in the dark about 1 to 2mm defuse glow at the tip of the needle) and the ionic wind was much weaker but still noticeable. That ionic wind was probably charging up anything insulated and deflecting the liquid. The first spot on switch on was on axis.

I need a better set up preferably with a variable HT supply and linear actuated to dispense the liquid. I also need to use a fiber forming liquid and or add a dye to the liquid to make it more visible. I also need to have only grounded metal after the washer and mount the paper on a metal plate

So this still crude apparatus proves 5kV across 10mm readily propels liquid from the blunt needle and projects it at least 30mm.

I will take some pics next time. The liquid stream is invisible to the naked eye even with a 25W LED light illuminating it from 300mm away. I am particularly curious as to how far the liquid can be propelled after it is accelerated by only 5kV


.




Borosilicate glass:
Good temperature resistance and good thermal shock resistance but finite.
For normal, standard service typically 200-230°C, for short-term (minutes) service max 400°C
Maximum thermal shock resistance is 160°C
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wg48temp9
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[*] posted on 31-12-2018 at 04:30


Here is a practiicalcal troubleshooting guide
Attachment: electro spinning.pdf (266kB)
This file has been downloaded 57 times
Leach, M.K., Feng, Z., Tuck, S.J., Corey, J.M. Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters. J. Vis. Exp.
(47), e2494 10.3791/2494, DOI : 10.3791/2494 (2011).

and a video and more excellent and practical info at https://www.jove.com/video/2494/electrospinning-fundamentals...


[Edited on 31-12-2018 by wg48temp9]




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[*] posted on 5-1-2019 at 12:05


Watching this f.y.i.

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[*] posted on 5-1-2019 at 16:24


Remember, I am not recording the vision of a madman. The sun does not more certainly shine in the heavens than that which I now affirm is true. Some miracle might have produced it, yet the stages of the discovery were distinct and probable. After days and nights of incredible labour and fatigue, I succeeded in discovering the cause of generation and life; nay, more, I became myself capable of bestowing animation upon lifeless matter.

Mary Shelley
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wg48temp9
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[*] posted on 6-1-2019 at 18:46


Quote: Originally posted by happyfooddance  
Watching this f.y.i.



I done some additional experiments. Perhaps surprisingly 5kV can propel the liquid from the needle tip to a grounded disc of stainless steel (base of a SS beaker) placed about 100mm away that is only about . 1.25kV/cm.

Below is a pic of the previous arrangement using a washer.

I presently boxing up the HT supply (a HT module from a photocopier) . adding a quad multiplier to the AC HT output to reach 20kV and adding about a 1:3 front panel voltage adjustment.

I am hoping to use a film forming solution, perhaps polystyrene dissolved in acetone. Apparently my red azo dye dissolves in acetone too.

Oops sorry apparently the system does not like my file format??? I think my new laptop hopeless.




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TheMrbunGee
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[*] posted on 7-1-2019 at 06:34


This was something completely new to me, thanks! Seems interesting!


Quote: Originally posted by wg48temp9  


I am hoping to use a film forming solution, perhaps polystyrene dissolved in acetone.



To my knowledge - polystyrene does not dissolve in acetone, it just softens creating a dough like blob sunk to the bottom of acetone.

But that's with styrofoam, not sure about purity of it.

[Edited on 7-1-2019 by TheMrbunGee]




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wg48temp9
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[*] posted on 7-1-2019 at 11:06


Quote: Originally posted by TheMrbunGee  
This was something completely new to me, thanks! Seems interesting!


Quote: Originally posted by wg48temp9  


I am hoping to use a film forming solution, perhaps polystyrene dissolved in acetone.



To my knowledge - polystyrene does not dissolve in acetone, it just softens creating a dough like blob sunk to the bottom of acetone.

But that's with styrofoam, not sure about purity of it.

[Edited on 7-1-2019 by TheMrbunGee]


i have had a similar experience using Styrofoam. I assumed it was cross-linked. I searched but I was not able to find any reference to confirm that. Apparently cross-linked polystyrene is made but only for specialist proposes which I now assume is not expanded polystyrene.

I was going to use solid material. I will try both.




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