Take the ionic polymer-metal composites (IPMCs) as a example. When being exposed to electrical field, an IPMC strip will experience shape-deformation due to the internal mechanical force induced by ionic motion inside the IPMC. Can anyone give a detailed physical explanation of how this mechanical force comes about? Or provide any publication or book ?
The strip is composed of Purfluorinated sulfonic acid polymer (Ionomer), with Platinum covered outside the strip. Then imposing a electric field on two side of the trip, the strip will bend due to electro-mechanical force.
Can you control the direction of bending by switching the electric field?
Yup, the direction of bending will be opposite, if the electric field is inverted.
Hi, Prof. Bharat, could u pls provide more detailed explanation of how the electric energy was transferred to mechanical energy in the underlying point of view, i.e. the electro-static force.
Jeannie,
It would appear that the bending arises from a mechanical pressure, induced by the migration of mobile cations in the polymer.
I'm using this paper as a guide:
'Quasi-static Positioning of Ionic Polymer-Metal Composite (IPMC) Actuators' by Chen, Tan, & Shahinpoor.
The electric field induces ion movement, the migration of which leads to an interstitial pressure, which results in mechanical strain.
Or so I gather.
Ah, I see that you've a further clarification. Well, the ions have work performed upon them - they're charged, and move a distance, and so one can calculate the integral of F.d to obtain the energy stored per unit volume (given a number density of ions). Energy per unit volume is just pressure, and the rest I leave as an exercise for the student.
:)
(or, I'm just lazy - I can't tell)
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