I am looking for a commonly available, non toxic material (i.e. on the market today for a relatively low price) that exhibits reasonable expansion and contraction in size when electricity is applied. This could be a gas, liquid, easily workable solid but ideally it would be a fabric or flexible rubber/plastic. I know there are jury-rigged (i.e., not currently on the market and requiring further development) ways of doing this using heat, I just was wondering if there is anything currently out there that would get the job done and ideally uses electricity directly and not through thermal expansion . Thanks.