hi all,
I am working on a micropump design and am using 100 um thick PDMS slygard
diaphragm as actuation valve to pump water. Now since PDMS is permeable to
moisture I need to coat another thin impermeable layer on it.
the properties of this second layer must be-
it must be flexible (so that pdms deflection is not compensated)
it must be transparent or optically clear
thin and easily available.

can anyone help or suggest me the solution to this problem??

thanks in advance,
Prasad.