Hey VIPEr Community,

I need your help! My senior thesis student is having some difficulties this year, reproducibly making V₂O₅ films via a sol-gel route.  The details of the synthesis are not important, but the key is that his films must "age" in a "wet" solvent environment before processing ("wet" in this context means isopropanol).  The method is to place the films, coated on a glass substrate and covered with a teflon-coated plastic cover slip, in a small dessicator that has a small beaker of isopropanol in the bottom.  If the atmosphere inside the dessicator becomes too saturated with iPrOH, and the films are left too long, they disappear.  If the films aren't aged long enough, the cover slip does not release cleanly in the next step and too much of the V₂O₅ film is ripped off.

My student thinks he is having difficulties achieving a reproducible vapor pressure of iPrOH in the dessicator depending on how long it has been closed up before use, lab temperature, etc.  What we need is some sort of nifty sensing device that we could use to figure out the current iPrOH vapor pressure in the dessicator.  Does anyone know of any simple colorimetric devices or molecules that might work here?

Thanks!

Maggie