PERMSELECTIVITY AND TEMPERATURE-DEPENDENT PERMEABILITY OF POLYANILINEMEMBRANES

An understanding of the mechanism of permeability in both doped and un doped polyaniline is obtained through permselectivity studies. Pervapo ration experiments are used to determine the permeability of carboxyli c acid/water mixtures through both doped and undoped polyaniline membr anes. Swellability experiments are used to determine solubilities, ena bling diffusivity values to be calculated. Doped polyaniline membranes show a marked improvement in separating water from carboxylic acid/wa ter mixtures as compared to undoped membranes, particularly in the cas es of acetic acid and propionic acid. However, the permeant fluxes of acetic acid/water mixtures through doped polyaniline membranes are low er than the fluxes through undoped polyaniline. The permeability behav ior of acetic acid, water and acetic acid/water mixtures are investiga ted between 20<degrees.C and 100<degrees.C. The flux of 50% acetic aci d/50% water mixtures through doped polyaniline doubles between 20<degr ees.C and 85<degrees.C, while the flux through undoped polyaniline ove r the same temperature range shows a 10-fold increase. From this data, the activation energies of permeation for 50% acetic acid/50% water a re calculated to be 2.5 kcal/mol through doped polyaniline membranes a nd 8.1 kcal/mol through undoped polyaniline.