Synthesis and characterisation of superhydrophilic conductive heterogeneous PANI/PVDF anion-exchange membranes

• PANI/PVDF anion-exchange membranes are prepared by wet and dry phase inversions.
• The prepared PANI/PVDF membranes are superhydrophilic and highly conductive.
• Increase of the PANI ratio results in an increase in membrane ion exchange capacity.
• The transport number is affected by the water content and porosity of the membrane.
• Achieve a better understanding of the relationships among various properties.

In this research, polyaniline (PANI)/polyvinylidene fluoride (PVDF) heterogeneous conductive anion-exchange membranes are prepared by a solution-casting technique using 1-methyl-2-pyrrolidone (NMP) as solvent and wet and dry phase inversion methods, various properties of these casted PANI/PVDF membranes are characterized. Most of prepared membranes exhibit properties of superhydrophilicity, high conductivity, good anion exchange capacity and high water content. The effects of the ratio of PANI and PVDF in the mixture on the properties of the prepared membranes are studied, including ion-exchange capacity (IEC), fixed ion concentration (FIC), transport number and water content. It is found that the increase of the PANI ratio in casting solutions resulted in an increase in membrane conductivity and IEC. However, the membrane transport number which represents the pathways for ionic transport is not controlled solely by an increase in the IEC, but rather, is more influenced by the water content and membrane porosity. Further, the results from this work lead to a better understanding of the relationships between conductivity and IEC, water content and transport number, which help to develop more efficient anion-exchange membranes for water purification and other industrial applications.