AN ABSORBENT ARTICLE COMPRISING A BREATHABLE BACKSHEET MATERIAL LAYER WHEREIN AT LEAST PARTS OF SAID LAYER COMPRISES 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 WILL INVOLVE AN ABRUPT CHANGE OF THE PERMEABILITY OF THE BREATHABLE MATERIAL LAYER.
