There was another article that I can't find now (probably from New Scientist) where they developed a plastic with microscopic holes or valves that let air in one way only. Because of the normal movement of air molecules, over time all the air inside a bag made of this material could escape, creating a vacuum inside the bag. If you reverse the material it becomes a self-inflating balloon. All with no external energy input.
That sounds like some cool stuff. I would think the Ziploc company would be jumping all over it.