It has long been known that wood is mildly piezoelectric.
Nobody, apparently, thought to wonder if cellophane was too.
It is

        http://sciencenow.sciencemag.org/cgi/content/full/2006/629/1

When voltage is applied across thickness it bends in the direction of 
the positive voltage.
Can be made to "flap" with applied voltage.

They gold plated each surface.
Other methods suggest themselves.
They mention microwave powering.

Should have potential for use in displays, along with a zillion other 
things.


Ref: Matthew McMahon 

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