I made some microchannels(50um wide, 3mm long and around 80um deep) by using SU8 2025 and silicon wafer, and then pour some PDMS and desiccate them for about 3 hours and them heat at around 120 until they fully cured.but after that I try to remove the PDMS slowly and it seems that all the PDMS channels are trapped inside the wafer and I got almost no channels on PDMS.
So, how to get rid of the PDMS that trapped inside microchannels and is there any way that I can solve this problem so that I can get good PDMS channels?
Thanks
I have experienced the same issue when I have not stirred the PDMS/Curing agent thoroughly. make sure you stir it for at least 5 minutes and make sure that the 10:1 ratio is conserved. Do not use curing agent more than this ratio. heating the mixture too much can also make some problems. I normally do the curing step at 80 C for 50 to 60 minutes. 120 C sounds a little bit too much, but, of course, it depends on how long you're curing them for.
If aforementioned tips did not help you whatsoever, it is possible that the aspect ratio of your channels (ratio of width to height) is so low and that is the source of the problem. In this case, it is recommended to either change the design, or use a surfactant that makes it easier for the PDMS to detach from silicon mask.
Good luck!
I am not sure what your problem is, maybe you could attach some pictures. It could be related to the curing of your PDMS or the silanization of your silicon master. Try following a standard fabrication procedure like this one: https://www.nanofab.ualberta.ca/wp-content/uploads/2009/03/boxedpdms.pdf
Hi Shiju gu,
Hope the below link answers your question,
https://www.researchgate.net/post/How_can_i_remove_sticky_PDMS_curing_agent_from_silicon_wafer
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