...are working by Coulomb's law of electrostatic. They are quite neat given their low manufacturing costs and not using moving parts (only the deforming elastomere) but is the return really worth it?
I'm not good with math but I see applications for the technology and before I put anyone to work on it it would be cool to know if for example a fleshlight made of this could keep a mobile screen lit? If DEG shoe soles could charge a capacitor to run a few LEDs?

I hope the spark of interest will make someone willing to explain what equations are involved in these example applications.

https://www.youtube.com/watch?v=5SIUuGRv3R0