BHM:
Thanks for posting. Without further detail it seems like a Maxwell's demon. The problem is that you need to have the droplets flow into "the top" (whatever that means) but not flow into the bottom. Simply hanging a film in the air should result in no net charge as the charged droplets would flow into both sides of the film. Are they using a vacuum pump to suck the droplets into the top? What is powering that pump? Also, it isn't clear how the droplets are becoming charged in the first place. A cloud in the wild has UV radiation impinging on it, creating charged droplets. But over time those free electrons find those charged droplets and they become neutralized. Certainly rain drops don't spark when they land so not all droplets are charged. So somehow they need to hang these films inside clouds (using an aerostat?) and run a pump to suck molecules through the film. Not saying it can't be done but these "engineering details" can make or break a technology. Fun to think about. Will be fascinating to see how far they go with it.

Rgds,
HH/Sean