Permeation behavior of Polysulfone membranes modified by fully organic Layer by Layer assemblies

This paper investigates the effect of the deposition of Layer by Layer assemblies on the swelling, permeability and anthracene rejection of polysulfone (PSf) membranes obtained through phase inversion precipitation technique. More specifically, these latter have been dip-coated on one side with a completely organic assembly (made of polyacrylic acid/branched polyethyleneimine bi-layers), varying the number of deposited bi-layers from 10 to 20. Prior the deposition, the surface of the polysulfone membranes has been subjected to plasma activation. Static contact angle, Scanning Electron Microscopy and attenuated total reflectance infrared spectroscopy measurements have been exploited for evaluating the modification of polysulfone after the LbL deposition, as well as the homogeneity of the distribution and coverage of the coatings on the polymeric substrate. The swelling of both untreated and LbL-treated membranes has been evaluated in three different solvents, i.e. methanol, isopropanol and n-hexane; subsequently, the permeation features of the treated membranes toward these solvents have been assessed and correlated with the presence of the deposited assembly; finally, the retention of anthracene in its n-hexane solutions has been evaluated.