An absorbent article includes a breathable backsheet material layer. At least a part of the layer includes a polymeric material exhibiting a discontinuous change in free volume in response to any of the following conditions or variables: liquid contact, the presence of certain ions, temperature and/or pH. One example of such polymeric materials is side chain liquid crystalline polymers which are able to undergo a phase transition between an isotropic phase and a nematic phase. The discontinuous change in free volume involves an abrupt change of the permeability of the breathable material layer.
