Abstract: This invention is directed to a tie layer for improving the adhesion of a layer of a fluoride-based polymeric material to a layer of a polyphenylene ether- or polystyrene-based material. The tie layer comprises a copolymer of a styrenic material like high impact polystyrene, and an acrylic material such as poly(methyl methacrylate) (PMMA). The tie layer composition may further include at least one flexibilizing agent which is compatible with one of the materials in the other layers. Exemplary flexibilizing agents are blends or copolymers which comprise rubber and polystyrene, or core-shell impact modifiers, or combinations of these types of materials. The layers can be coextruded or laminated, using conventional techniques.