Dear Yogendra,

a former colleague of mine used porous Si thin layer, porous poly-Si, or
porous Si-C for humidity sensor, and also for other gas sensor. Perhaps
you can try it.

Please have a look at:
http://scholar.google.com/scholar?hl=en&lr=&cluster=1649166982137917822

regards,

Dedy

Yogendra Yadav_04322601 wrote:
> Dear All,
> I am working on microcantilvere based humdity sensor. i have made the
> device i.e microcantilver of nitride and oxide. for sensing film i
> want to use polyimide but i have not been able to get for long time.
> it is because the polyimide now a days has been made to have less
> water absorbing capacity. the earlier series which i want to use is
> not availabale anywhere.
>
> I request plz anyone can help me in finding option for polyimide which
> i can use as sensing film on my cantilever to detect the moisture.