Investigation of the formation characteristics of polyaniline and its application in forming free-standing pressure filtration membranes

PANI particles were synthesised through the chemical polymerisation of an ammonium persulfate (APS) and aniline (ANI) solution with/without lithium chloride (LiCl) at different reaction times (6-24 h) and temperatures (3-24 degrees C). SEM images, along with GPC results, confirmed that PANI synthesised at different parameters affects the PANI morphology and molecular weight (MW). Meanwhile, TGA and DSC results represent the thermal properties of synthesised PANI and reveal that PANI without LiCl addition has the lowest melting temperature. Based on the results, the best PANI was successfully synthesised at a temperature of 3 degrees C and at a reaction time of 6 h with the addition of LiCl. A free-standing PANI membrane was obtained through phase inversion upon using PANI in NMP/4MP of 18, 20, and 23 wt%. A rejection study showed that the free-standing PANI membrane with 23 wt% concentration was in nanofiltration (NF), whereas others were in the ultrafiltration (UF) range.