A polymer-metal junction, comprising: - a metal substrate in contact with - a polymer composition comprising a PEEK-PEmEK copolymer, the copolymer comprising at least 50 mol %, collectively, of repeat units (R PEEK) and repeat units (R PEmEK), relative to the total number of repeat units in the PEEK-PEmEK copolymer, wherein: (a) repeat units (R PEEK) are repeat units of formula: and (b) repeat units (R PEmEK) are repeat units of formula: wherein: each R 1 and R 2, equal to or different from each other, is independently at each occurrence selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, each a and b is independently selected from the group consisting of integers ranging from 0 to 4, and the PEEK-PEmEK copolymer includes the repeat units R PEEK and R PEmEK in a molar ratio R PEEK /R PEmEK ranging from 95/5 to 45/55. - a metal substrate in contact with - a polymer composition comprising a PEEK-PEmEK copolymer, the copolymer comprising at least 50 mol %, collectively, of repeat units (R PEEK) and repeat units (R PEmEK), relative to the total number of repeat units in the PEEK-PEmEK copolymer, wherein: (a) repeat units (R PEEK) are repeat units of formula: and (b) repeat units (R PEmEK) are repeat units of formula: wherein: each R 1 and R 2, equal to or different from each other, is independently at each occurrence selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, each a and b is independently selected from the group consisting of integers ranging from 0 to 4, and the PEEK-PEmEK copolymer includes the repeat units R PEEK and R PEmEK in a molar ratio R PEEK /R PEmEK ranging from 95/5 to 45/55. (a) repeat units (R PEEK) are repeat units of formula: and (b) repeat units (R PEmEK) are repeat units of formula: wherein: each R 1 and R 2, equal to or different from each other, is independently at each occurrence selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, each a and b is independently selected from the group consisting of integers ranging from 0 to 4, and the PEEK-PEmEK copolymer includes the repeat units R PEEK and R PEmEK in a molar ratio R PEEK /R PEmEK ranging from 95/5 to 45/55. each R 1 and R 2, equal to or different from each other, is independently at each occurrence selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium, each a and b is independently selected from the group consisting of integers ranging from 0 to 4, and the PEEK-PEmEK copolymer includes the repeat units R PEEK and R PEmEK in a molar ratio R PEEK /R PEmEK ranging from 95/5 to 45/55.