Design and Fabrication of Regenerable Polyelectrolyte Multilayers for Applications in Foulant Removal

Regenerable polyelectrolyte multilayers (PEMs) are prepared on the basis of a sacrificial block of polyelectrolyte on the top of a non-removable PEM. Poly(allylamine hydrochloride) (PAH) and polyestyrene sulfonate (PSS) PEMs with a block of poly(diallylmethylammonium chloride) (PDADMAC)/PSS on top; PAH/PSS with PDADMAC/poly(acrylic acid) (PAA) on top; and polyethylenimine (PEI)/PSS with PEI/PAA on top are fabricated. The top PDADMAC/PSS and PEI/PAA blocks are removed by interaction with (1-tetradecyl) trimethylammonium bromide and sodium dodecylsulfate surfactants, respectively, whereas PDADMAC/PAA is removed by exposure to basic pH. The supporting PEMs are not removed. The PEMs are coated with bovine serum albumin (BSA) as a model foulant. The top block is removed together with the BSA. After removal of the top block, the film is regenerated by assembling polyelectrolyte layers with the same composition as the original top block. Removal and regeneration are followed by quartz crystal microbalance measurements with dissipation, atomic force microscopy, fluorescence spectroscopy, and X-ray photon electron spectroscopy.