Hi, Tushar,

I tried to repeat this experiment for a long time. I did not get a good pattern
neither.

Both pre-exposure bake and post-exposure bake are required since the mixture is
negative-photoresistance type material.

I usually disolve the DMAP into Xylenes and then pour the DMAP+Xylenes mixture
in to PDMS.

I got help form this discussion group to change DMAP to other photoiniatior to
match the UV wavelength of my aligner. Otherwise, exposure time will be 1 hour
or more.

I have use Sylgard 184 (Dow Corning) and RM-033(Gelest).Actually, the amounts
of each chemical to use have been reported in several papers and this discussion
group. PDMS : Xylenes : DMAP = 100:2:1 (weight ratio)

Just recently, Dow Cornning has a new product, photopatternable spin-on
silicone. Please check its website to see whether it is suitable for your
application.

Good luck

Lydia



Quoting Tushar  Bansal :

> Hello Everyone,
> I am trying to make photopatternable PDMS. I am using methacrylate
> terminated PDMS and mixing it with Xylenes and DMAP (DMAP is the
> photoinitiator, Xylenes is a thinner). This solution was reported in
> several papers. However, it is polymerizing far too quickly and the DMAP
> is not dissolving. Furthermore, on exposure and development, no actual
> pattern is observed. Are we missing a step in this procedure? The amounts
> of each chemical to use were not reported in the papers.
>
> Please suggest any missing steps to the above procedure or any alternate
> procedures to achieve a photo patternable PDMS.
>
> Thanks,
> Tushar
>
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