Hi TJ,

Do you bond your PDMS to a glass slide? If you do your microscopy through the
glass, a solution could be to make black PDMS - in this case the rhodamine
diffusing into the PDMS won't bother you so much.

To make black PDMS, just add ~1g of black printer toner per 50-60 g of PDMS
during mixing. Good luck!

Regards,

Dirk Renckens
TUDelft Chem Eng PhD candidate

-----Original Message-----
From: 김태진 [mailto:tjnumber1@hotmail.com]
Sent: 20 September 2009 02:03
To: mems-talk@memsnet.org
Subject: [mems-talk] flowing in rhodamine in pdms channel

Hi all,

I've been trying to flow in fluorescence die (Rhodamine) in a PDMS microfluidic
channel to do some flow characterizations.

The problem is, the vicinity of the pdms channel became bright as well after
about 5 minutes.

It almost seemed like that the fluoresent die was diffused into the pdms.

Is there a way to solve this problem?

Thanks!

TJ