Polyelectrolyte Multilayers Composed of Chitosan and Poly(acrylic acid) I. Deposition conditions and post-treatment strategies

Polyelectrolyte multilayers composed of chitosan and poly(acrylic acid) were constructed onto silicon wafers from solutions of different concentrations of polymer and NaCl. To modulate the film properties, the multilayers were subject to three post-treatment strategies: W immersion in an aqueous solution with pH = 2.4 for I min, followed by a 15s immersion step in water and drying at 80 degrees C for 60 min; (ii) immersion for 30 min in water and (ill) immersion in an aqueous solution with pH = 2.4 for 5 min, followed by immersion for I min in water and thermal treatment at 120 degrees C for 60 min. The changes of the film morphology, thickness, and wetting state as a function of deposition conditions and post-treatment strategies used were followed by atomic force microscopy, spectroscopic ellipsometry and contact angle measurements.