Ethylene copolymers have been widely used in packaging applications. The ethylene ionomers achieve unique property characteristics through development of network morphology which imparts outstanding clarity, drawability, toughness, and abrasion resistance. In this paper we discuss the development of ionomers with novel performance: that is, selective gas transmission is greatly increased while mechanical properties are maintained. We show the effect of composition on morphology and demonstrate the utility of these novel compositions in packaging applications requiring high selective breathability.