A composition [composition] comprising: - at least one polyaryl ether ketone copolymer [copolymer (PEDEK-PEEK)] comprising: - recurring units (R PEEK) of formula: and - recurring units (R PEDEK) of formula: wherein in above formulae and, each of R and R", equal to or different from each other, is independently selected at each occurrence from a C 1 -C 12 group optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups; each of j' and k", equal to or different from each other, is independently selected at each occurrence from 0 and an integer of 1 to 4; wherein the said recurring units are comprised in a molar ratio (R PEDEK): (R PEEK) of 55:45 to 99:1, and - at least one sulfone polymer [polymer] selected from the group consisting of: (PS-1) polyphenylsulfone polymers [polymer (PPSU)] comprising more than 50 mol %, with respect to all recurring units, of recurring units (R PPSU) of formula (P-1): wherein - each R PPSU, equal to or different from each other at each instance, is independently 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 d, equal to or different from each other at each instance, is independently selected from 0, 1, 2, 3 and 4, preferably 0; and (PS-2) polyethersulfone polymers [polymer (PESU)] comprising more than 50 mol %, with respect to all recurring units, of recurring units (R PESU) of formula (P-2): wherein - each R PESU, equal to or different from each other at each instance, is independently 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 e, equal to or different from each other at each instance, is independently selected from 0, 1, 2, 3 and 4, preferably 0. - at least one polyaryl ether ketone copolymer [copolymer (PEDEK-PEEK)] comprising: - recurring units (R PEEK) of formula: and - recurring units (R PEDEK) of formula: wherein in above formulae and, each of R and R", equal to or different from each other, is independently selected at each occurrence from a C 1 -C 12 group optionally comprising one or more than one heteroatoms; sulfonic acid and sulfonate groups; phosphonic acid and phosphonate groups; amine and quaternary ammonium groups; each of j' and k", equal to or different from each other, is independently selected at each occurrence from 0 and an integer of 1 to 4; wherein the said recurring units are comprised in a molar ratio (R PEDEK): (R PEEK) of 55:45 to 99:1, and - at least one sulfone polymer [polymer] selected from the group consisting of: (PS-1) polyphenylsulfone polymers [polymer (PPSU)] comprising more than 50 mol %, with respect to all recurring units, of recurring units (R PPSU) of formula (P-1): wherein - each R PPSU, equal to or different from each other at each instance, is independently 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 d, equal to or different from each other at each instance, is independently selected from 0, 1, 2, 3 and 4, preferably 0; and (PS-2) polyethersulfone polymers [polymer (PESU)] comprising more than 50 mol %, with respect to all recurring units, of recurring units (R PESU) of formula (P-2): wherein - each R PESU, equal to or different from each other at each instance, is independently 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 e, equal to or different from each other at each instance, is independently selected from 0, 1, 2, 3 and 4, preferably 0.