I want to fabricate the microneedle. At the first, I should to print the master mold. Then, I cast the PDMS over the master mold to produce negative mold. At the end, polymer-drug solution is cast over PDMS mold to fabricate the microneedle.
but, I do not know, what is the difference between the size of the master mold and the dimension of PDMS mold and the final microneedle?
If you are preparing polymeric microneedles, generally the size of the final microneedles obtained after drying is smaller than the mold dimension. The mold with 500 micron height size is able to produce MN of size 450-470 micron. So both molds and final MN obtained need to be characterised.
The size difference between the master mold and the PDMS replicate is quite small, between 1 and 2.5%, and depends on the PDMS ratio and curing temperature. See this article for more info:
Article Shrinkage ratio of PDMS and its alignment method for the waf...
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