Abstract: A method of preparing a relatively stable solution and/or dispersion of an ion-conducting polymeric material, for example one comprising phenyl moieties, carbonyl and/or sulphone moieties and ether and/or thioether moieties, comprises: (a) selecting a solvent mixture comprising water and a first organic solvent in which mixture said ion-conducting polymeric material can be dissolved and/or dispersed; (b) dissolving and/or dispersing said ion-conducting polymeric material in said solvent mixture; and (c) removing greater than 80% of the total amount of said first organic solvent in said solvent mixture, thereby to leave a formulation comprising said ion-conducting polymeric material dissolved and/or dispersed in a solvent formulation comprising a major amount of water.

Abstract: A fuel cell powered by direct fuel, for example a direct methanol fuel cell, includes a polymer electrolyte membrane which includes a semi-crystalline polymer. Preferred semi-crystalline polymers include first repeat units comprising sulphonated aromatic group containing moieties linked by —SO2— and/or —CO— and/or -Q-groups, where Q is O or S and second repeat units which include aromatic group containing moieties linked by —CO— and/or Q groups.

Abstract: A method of preparing an ion-conducting material, for example membrane, having reduced sensitivity to water includes a step of treating an ion-conducting polymeric material (especially a sulphonated polyaryletherketone and/or sulphone) which has at least some crystallinity or which is crystallizable with a means to increase its crystallinity. The ion-conducting material prepared may be used in a Membrane Electrode Assembly of a fuel cell.

Abstract: A fuel cell powered by direct fuel, for example a direct methanol fuel cell, includes a polymer electrolyte membrane which includes a semi-crystalline polymer. Preferred semi-crystalline polymers include first repeat units comprising sulphonated aromatic group containing moieties linked by —SO2— and/or —CO— and/or -Q-groups, where Q is O or S and second repeat units which include aromatic group containing moieties linked by —CO— and/or Q groups.

Abstract: A method of preparing an ion-conducting material, for example membrane, having reduced sensitivity to water includes a step of treating an ion-conducting polymeric material (especially a sulphonated polyaryletherketone and/or sulphone) which has at least some crystallinity or which is crystallisable with a means to increase its crystallinity. The ion-conducting material prepared may be used in a Membrane Electrode Assembly of a fuel cell.