Résumé
The aim of this work is to prepare wound dressing hydrogels permitting (i) tocure chronicle pathologies; (ii) to remove unsuitable odors coming from healing.Thus, chitosan, a natural polymer with biological properties, and activated carbon(AC), a well-known adsorbent, are mixed within a composite hydrogel. To get asuitable porous structure for healing, the vapor induced phase separation process(VIPS) is used. It permits to slow down mass transfers kinetics compared to otherelaboration processes such as the wet process. Hence, a better control of the finalporous matrix is reached throughout the elaboration process.In this work, the mass transfers occurring through the elaboration of the com-posites were studied thanks to gravimetric measurements carried out during theVIPS process. Results showed there were two main steps in the gelation process.A weight intake, due to an ammonia flux allowing the gelation to happen, wasfollowed by a weight loss, mainly controlled by a water outtake. This second partcould be compared to a slow drying in smooth conditions. Gelation with a colorindicator was also performed, which provided complementary experimental infor-mation on mass transfers barrier.A modeling of mass transfers mechanisms occurring during the gel elaborationis presented to get an overview of limiting phenomena leading to the final com-posite structures. It involves a coupling between chemical reactions, external masstransfers and internal diffusion within the polymeric matrix. Results show that in-ternal diffusion is the main barrier to gelation.To qualify the gel structure, drying kinetics were compared on the elaborated gels.Whatever the gel, the drying kinetics were globally the same and could be dividedinto three steps. Considering the process used and this result, it was believedthat the matrixes prepared were homogeneous and rather symmetric. They couldconstitute the first layer of wound dressings.