Physical properties of extrusions such as films, sheets, and tubes depend on the arrangements and shapes of polymer components at the microscopic scale. Consequently, co-extrusion is not necessarily the best process for optimizing multiple properties. This presentation describes how a new practical processing technology, chaotic or “smart” blending, is implemented for fabricating extrusions of nylon and ethylene-vinyl alcohol random copolymer (EVOH) that demonstrate low oxygen permeation, high impact toughness, and reduced solvent penetration. Chaotic blending intrinsically develops blends with high interfacial area, so it has special applicability to barrier films, packaging, and membranes.