Preparation of chitosan gel

Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying

Study of interaction between chitosan and active carbon in view of optimising composite gels devoted to heal injuries

In order to develop biomaterials useful in reconstructive surgery, mechanism of adsorption of chitosan onto activated carbon has been investigated. Activated carbons have been characterised using SEM, NH3 adsorption and 129Xe NMR spectroscopy. Adsorption of chitosan on activated carbon in acid aqueous solution increases when the degree of acetylation of chitosan decreases. Sterilization does not modify the adsorption capacity of the studied sample of activated carbon

Formation mechanism of anthracene dimers and excimers in NaY zeolitic nanocavities

The dimer and the excimer formation mechanisms of anthracene in NaY zeolitic nanocavities have been studied by using various spectroscopic techniques of 129Xe NMR, diffuse reflectance, and emission as well as time-resolved fluorescence. Two anthracene molecules adsorb concertedly into a zeolitic supercage to form a ground-state stable dimer. An excited monomer in a singly occupied supercage gives birth to an excimer if another monomer exists in a tetrahedrally connected nearest supercage. An excited monomer forms a nonluminescent ion pair with a monomer in a nearest supercage by transferring an electron within 100 ps. The dark intermediate rearranges to transform into an excimer on the time scale of 400 ps.close161