TECHNOLOGY FOCUS - POLYMERS - The ion-conductive copolymer is of formula (((-(Ar1-T-)i-Ar1-X-)a)m/((-Ar2-U-Ar2-X-)b)n/((-(Ar3-V-)j-Ar3-X-)c)o/((-Ar4-W-Ar4-X-)d)p/).Ar1 - Ar4 = aromatic moieties (preferably optionally substituted phenyl, napthyl, terphenyl, or optionally substituted aryl nitrile);T, U, V and W = linking moieties (preferably bond, -C(O)-, -C(CH3)2-, -C(CF3)2-, -S(O)2-, -CH2-, fluorene-9,9-diyl, -O-, -O-(1,4-phenylene)-O-, -C(CH3)2-(1,4-phenylene)-C(CH3)2-, -C(CH3)2-(1,3-phenylene)-C(CH3)2-, );X = -O-, or -S-;i and j = greater than 1;a - d = mole fractions; andm - p = integers indicating the number of different oligomers or monomers in the copolymer.Provided that(1) at least one of Ar1 or Ar2 comprises an ion-conducting group;(2) a+b+c+d is 1; and(3) a is greater than or equal to0 (preferably 0.3) and then at least one of b - d are greater than 0. EXAMPLE - In a round flask (500 ml), equipped with a mechanical stirrer, a thermometer probe connected with a nitrogen inlet, and a Dean-Stark trap/condenser, 4,4'-difluorobenzophone (28.36 g), 4,4'-dihydroxytetraphenyhnethane (34.36 g), and anhydrous potassium carbonate (17.51 g), dimethyl sulfoxide (234 ml) and toluene (117 ml). The reaction mixture was slowly stirred under a slow nitrogen stream. After heating at 85degreesC for 1 hours and at 120degreesC for 1 hours, the reaction temperature was raised to 135degreesC for 3 hours, and finally to 170degreesC for 2 hours. After cooling to 70degreesC with continuing stirring, the solution was dropped into cooled methanol (2 liter) with a vigorous stirring. The precipitates were filtrated and washed with Di-water four times and dried at 80degreesC for one day and at 80degreesC under a vacuum oven for 2 days to obtain oligomer (A1).In the necked round flask (50 ml), equipped with a mechanical stirrer, a thermometer probe connected with a nitrogen inlet, and a Dean-Stark trap/condenser, oligomer (A1) (20.90 g), 4,4'-difluorobenzophone (15.50 g), 4,4'-(hexafluoroisopropylidene) diphenol (26.90 g), and anhydrous potassium carbonate (14.37 g), were added together with a mixture of anhydrous dimethylsulfoxide (240 ml) and freshly distilled toluene (120 ml). The reaction mixture was slowly stirred under a slow nitrogen stream. After heating at 85degreesC for 1 hour and at 120degreesC for 1 hour, the reaction temperature was raised to 140degreesC for 2 hours, and finally to 163degreesC for 2 hours. After cooling to 70degreesC with continuing stirring, the viscous solution was dropped into cooled methanol (1 liter) with a vigorous stirring. The noodle-like precipitates were cut and washed with di-water four times and and then dried at 80degreesC overnight and at 80degreesC under vacuum for 2 days to obtain a polymer having an inherent viscosity of 0.40 dl/g in dimethyl acetamide (0.25 g/dl).