FABRICATION OF NANO-STRUCTURED SURFACES BY FINE TUNING OF DEPOSITION PARAMETERS IN CHITOSAN/PSS POLYELECTROLYTE MULTILAYERS

The fabrication of chitosan/polystyrene sulfonate (CHI)/(PSS) polyelectrolyte multilayer on different polymeric supports (polyether sulfone, polycarbonate and nylon), is discussed in the present work. The permeation of model protein BSA through these multilayer membranes was carried out under ultrafiltration conditions. Different multilayer systems were prepared by varying the parameters such as nature of the polymeric support, pH and molecular weight of polyelectrolyte. Build up of multilayers on polymeric support was monitored by measuring area under the sulfonate peak at 1033 cm-1 in the FTIR spectrum. No appreciable rejection of BSA was observed when CHI/PSS multilayers were fabricated on polycarbonate and nylon supports even after 15 bilayer coating. When multilayers were fabricated on polyether sulfone membranes, more than 90% rejection of BSA was observed with 5 bilayer coated membrane. This study reveals that pH and molecular weight of the polyelectrolyte has decisive role in the multilayer build up.