Plastic packaging for food contact is evolving to meet current environmental challenges. Poly (ethylene terephthalate) (PET) is a very good candidate because of its efficient recycling process, but it is very often complexed or coated with materials highly incompatible with this process. The addition of poly (ethylene furanoate) (PEF), a biosourced polyester with a close chemical structure but with better properties, is then a way for the development of recyclable barrier films. The properties of the PET/PEF films can then be optimized using multinanolayer coextrusion and biaxial stretching processes, allowing polymer nanostratification. However, the mechanical properties of the films produced must also meet specifications, since interfacial adhesion plays a major role on these properties in the case of multilayer structures. The aim of the project is therefore to develop a method for quantifying this interfacial adhesion based on the compatibility between polymers, but also on the effects of confinement and multiplication of interfaces.