Investigation on electrical tuneable separation properties for phase inversion polyaniline membranes doped in various acids

Electrically tuneable polyaniline (PANI) membranes were fabricated via phase inversion and were doped primarily in various acids namely anthraquinone sulfonic acid (ASA), dodecylbenzene sulfonic acid (DBSA), maleic acid (MA) and poly(methyl vinyl ether-alt-maleic acid) (PMVEA) in comparison with secondarily HCl-doped PANI membrane as the pristine ones. It was found that the addition of different dopants in the PANI matrix changed the thickness of the membrane skin structure. From the dynamic contact angle (DCA) analysis, the PANI-ASA and pristine PANI membranes had the greatest permeation tuneability with a faster permeation rate under electric potential. For the effect of tuneable filtration, by using a modified cross-flow membrane filtration system, ASA showed the highest flux tuneability with a tuneable MWCO in the low UF range at an applied voltage of 7 V rather than at 0 V. Accordingly, the electrical tuneability assessment of the membranes has successfully demonstrated the proof of concept that the fabricated PANI membranes doped at various acids could have a different tuneable MWCO, selectivity and/or flux in a pressure filtration system.