Governing equations for one-dimensional ionic polymer-metal composites are reviewed and then cast into the framework of a variational statement. Starting from a trial-Lagrangian, a generalized functional is derived through a systematic procedure of the semi-inverse method proposed by Ji-Huan He. All field equations and boundary conditions are cast into Euler equations of the obtained functional,, leading to much convenience in incorporating analytical and numerical approaches. (C) 2003 Elsevier Ltd. All rights reserved.