The problems are size and shape change as it saturates and losing structural integrity (soggy...). Capacitors are a nice example, they're always wrapped in something else both to contain the fluid and to keep things in one place.

Any kind of acidity would also be taboo. It would be very hard I think to make something like this but I'm more than willing to admit that none of these are 'dealbreakers'. That's why I asked about the application, after all, if that's the only way to do it and the application is valuable enough then maybe there is a reason to invest a large amount of $ for R&D.