Abstract: The invention provides a packaging material which comprises a polymeric base component and a barrier component which coats and lines a surface of the base component, the barrier component inhibiting migration of gases, vapors and liquids through the base component. The barrier component comprises a polymeric layer comprising at least two different polymeric species which are polar and which are water soluble. The different species have different chemical compositions and are complementary in that they are bound together physically by interpolymer complexation to form an interpenetrating physical network. The invention also provides a process for producing the packaging material which comprises coating at least one surface of the base component with the barrier component and causing the complementary species to interact together physically by interpolymer complexation to form an interpenetrating physical network.