Hi,

Epoxies in general are hydrophilic (contain OH-groups) while PDMS has lots of methyl groups and by nature is hydrophobic. This means these molecules don't like each other. You can try making PDMS hydrophilic by plasma or ozon treatment or by using a primer on top of epoxy (primers need OH-groups) which makes it hydrophobic on the outside. A strong bond you will probably never get, PDMS has the nasty property to rearrange its molecular bonds so after a while a epoxy-PDMS bond will deteriorate.

Hi Peter Knapen,

Many thanks for your explanations. It's really helpful to me. Thanks.

Hello Anirban,

As Peter states, most techniques activate the surface with plasma or UV-ozone. For bonding PDMS to SU-8 I have used a combination of UV-ozone and silanisation with APTES. The processing of the SU-8 (post-exposure and hardbake) can affect the results due to the available epoxy groups on the surface.

Some papers you may find useful:

http://www.mdpi.com/2072-666X/6/12/1465

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3364813/

http://ieeexplore.ieee.org/document/6857985/

Hello Anirban,

If you have challenges already about bonding, you can try holders keeping PDMS and epoxy together. We can provide custom chip holder and fittings production.

www.nehirbt.com.tr

Best wishes

Serhat