Perhaps the solution is penetrating the film. Or perhaps it modifies the
films, by creating charge carriers in it.

Ed

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org] On Behalf Of Michael D Martin
Sent: Thursday, January 10, 2008 1:49 PM
To: MEMS Talk
Subject: [mems-talk] Polyimide and Parylene Ionic conductivity

We're working on a biomems application where we are relying on the high
electrical resistance of polyimde in an ionic aqueous environment (1M
KCl).  We have found though that the bulk resistivity of PI-2611 in this
solution is only 8.3 x 10^11 Ohm-cm vs. the published value from HD
Microsystems of >10^16 Ohm-cm!  We see a similar affect on parylene .
Can anyone comment? Have you seen this before?