  Ionic electro-active polymers (E.A.P.) is an active material consisting in a
polyelectrolyte (for example Nafion). Such material is usually used as thin
film sandwiched between two platinum electrodes. The polymer undergoes large
bending motions when an electric field is applied across the thickness.
Conversely, a voltage can be detected between both electrodes when the polymer
is suddenly bent. The solvent-saturated polymer is fully dissociated, releasing
cations of small size. We used a continuous medium approach. The material is
modelled by the coexistence of two phases; it can be considered as a porous
medium where the deformable solid phase is the polymer backbone with fixed
anions; the electrolyte phase is made of a solvent (usually water) with free
cations. The microscale conservation laws of mass, linear momentum and energy
and the Maxwell's equations are first written for each phase. The physical
quantities linked to the interfaces are deduced. The use of an average
technique applied to the two-phase medium finally leads to an Eulerian
formulation of the conservation laws of the complete material. Macroscale
equations relative to each phase provides exchanges through the interfaces. An
analysis of the balance equations of kinetic, potential and internal energy
highlights the 2 Mireille Tixier, Jo{\"e}l Pouget phenomena responsible of the
conversion of one kind of energy into another, especially the dissipative ones
: viscous frictions and Joule effect.
