I have a ABS mold that I am using to cast PDMS. The issue is that after curing PDMS, the hydrophobic layer sticks to the plastic that every attempt to release the product ends up messing it. We were thinking that if we treat the ABS to have thin film of hydrophillic layer before we pour in the PDMS, it might slightly reduce its affinity with mold, and make it easier to release it. Any help will be gladly appreciated
Try coating the ABS surface with a fluorine-based surfactant by dissolving a small amount of said surfactant in acetone and wiping the mold surface with said surfactant-acetone solution. The hydrophobic moiety might be adsorbed onto the ABS leaving the hydrophilic tail to form a steric barrier against the PDMS surface
Hi Henintsoa
I assume you are using Sylgard 184 which can get stuck to molds often.
What size structures do you have?
I do not think making your mold hydrophilic will help.
Have you tried vapor depositing fluorosilane on the ABS?
If you have flexibility on the silicone material choice, you might have luck moving away from 184 if that is what you are using.
Andrew H. Cannon, Ph.D.
researchmicrostamps.com
Thank you Dan,
We will attempt this method. Would baking the mold to cure the PDMS affect the stability of the hydrophilic barrier?
Thank you Dr. Cannon,
Yes we are using 184, the layer that we are making is in the macro range actually above
Hi Henintsoa - obviously the surfactant molecule would be affected if the baking temperature is too high - so check the specification sheet for the surfactant you chose to understand it's stability. I specifically suggested a surfactant which should offer some resistance to temperatures. There are some commercially available mold release agents (silicon based) which might work also. The field of injection molding would be good for you to look into. There the mold is typically steel and the molded part is typically some polymer material, like poly carbonate etc.
If you're making macro structures, you could try the mold releases from Smooth-On
https://www.smooth-on.com/support/faq/101/
Andrew H. Cannon, Ph.D.
researchmicrostamps.com
Thank you Dr. Cannon for your recommendation, we look at our best option.
Hi Henintsoa, Have you found a solution to the above problem? I am facing something similar.
Thanks!
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