Polymer membrane, method for the production and use thereof

A doped polymer membrane based on polyazoles, obtained by a process comprising the steps

• A) casting a film using a solution of polymers based on polyazoles in a polar, aprotic organic solvent,
• B) drying the film formed in step A) until it is self-supporting to form a dried film, said dried film having a residual content of said polar, aprotic organic solvent in a range of 10 to 23%,
• C) treating the film obtained in step B) with a treatment liquid at a temperature in the range from 20° C. to the boiling point of the treatment liquid, where said treatment liquid is selected from the group consisting of:
• water, acetone and methanol,
• D) drying and/or dabbing the film treated according to step C) to remove the treatment liquid from step C),
• E) doping the film treated according to step D) with a doping agent, where said doping agent is selected from the group consisting of:
• sulfuric acid and phosphoric acid,
• where said doping is performed for 1 to 96 hours at a temperature ranging from 20° C. to 100° C. and said doping agent has a concentration of 85%, and
• where doping is of a degree from 3 to 15 mol of acid per mol of recurring unit of polymer.