The air is connected through tiny tubelets and can be sucked out or pumped back in, a little bit like a lung.
-- pashute, Aug 23 2022

Liquids and Gases - Boiling Points https://www.enginee...ds-gases-d_155.html
[xaviergisz, Aug 25 2022]

I disagree that it has been made, the foam in the (massively overbroad) Goodyear patent isn't inflatable, just compressible. There are no air pockets comprising the foam.

But I can't bun this because a mechanism for manufacture isn't addressed, and that's the only real reason this hasn't been made.
-- Voice, Aug 23 2022


//mechanism for manufacture// You'd use a 3-d printer with a miniature blow-molder set in the tip. The molder forms a miniature spherule with a vent; the printer then places it in the base matrix. I think it's likely they would be printed as flat beds, then the beds rolled to form tubes with all the cell vents on the inside of the tube. The tubes in turn attach to the bronchi of your structure.

Since I haven't been able to imagine a way for these things to create mucus, there will need to be some filtration to keep the alveoli clean.
-- lurch, Aug 24 2022


//keep the alveoli clean//
Rather than a "one ended" balloon, each cell could be a tube ("double ended"), & the system as a whole is also "doubled ended". Then you can clean by blowing through the whole thing (blow one end, other open), while still able to inflate (blow both ends) & deflate (suck both ends). Slightly more complex valving, but not much.
-- neutrinos_shadow, Aug 25 2022


Each cell of the foam could be filled with a substance that has a solid-gas or liquid-gas phase change at a convenient temperature.

Below that temperature each cell would collapse, and above that temperature each cell would expand.
-- xaviergisz, Aug 25 2022



random, halfbakery