CLAUDIU-AUGUSTIN GHIORGHITA, FLORIN BUCATARIU, MARCELA MIHAI, ECATERINA STELA DRAGAN POLYELECTROLYTE MULTILAYERS COMPOSED OF CHITOSAN AND POLY(ACRYLIC ACID)II. SORPTION/RELEASE OF METHYLENE BLUE Chitosan (CHI) and poly(acrylic acid) (PAA) polyelectrolyte multilayers were constructed onto silica microparticles with particle diameter of 40 – 60 mm (Daisogel type). The multilayers were subject to two post-treatment strategies: (i) immersion in an aqueous solution with pH = 2.4 for 5 min, followed by immersion for 1 min in water and thermal treatment at 120oC for 60 min and (ii) cross-linking with glutaraldehyde for 60 min. The sorption properties for a cationic dye were investigated taking methylene blue (MB) as a model. The reusability of (CHI/PAA)n multilayers deposited onto Daisogel microparticles in the consecutive sorption/desorption cycles of MB was investigated as a function of the number of double layers and the post-treatment strategy.