High aspect ratio PDMS replication through proton beam fabricated Ni masters

In application areas where multiple samples are required (for example tissue engineering substrates), proton beam writing (PBW) is a suitable technique to fabricate high quality metal masters. These masters can then be used to replicate multiple copies in polymers, either through nanoimprinting or softlithography. Since poly(dimethyl siloxane) (PDMS) is a compatible material in tissue engineering we explore PDMS casting on Ni masters as an alternative way to replicate high aspect ratio micro structures. Ni masters with grooves spaced 2.5 μm apart, and 13 μm deep were successfully replicated in PDMS: These PDMS structures, which have aspect ratio of more than 5, are comparable to the best high aspect ratios reported in PDMS replication.