Continuum of structural organization from chitosan solutions to derived physical forms.

The structural organization of chitosan, a cationic polyelectrolyte, in aqueous solutions of high ionic strength, is investigated by quasi-elastic light scattering and wet scanning transmission electron microscopy. The formation of submicrometric chain aggregates driven by hydrophobic interactions is evidenced. These heterogeneities are at the core of the multiscale morphology of physical hydrogels processed from this polysaccharide.

Structure of natural polyelectrolyte solutions: role of the hydrophilic/hydrophobic interaction balance.

A method allowing the evaluation of the solvophilic/solvophobic character of polyelectrolytes from their conformation in solution is discussed. Analyzed systems are salt-free aqueous solutions of natural copolysaccharides with controlled chemical structures. Small-angle X-ray scattering diagrams revealed their conformation by the "polyelectrolyte peak".

Mechanisms involved during the ultrasonically induced depolymerization of chitosan: characterization and control.

The existence of two mechanisms involved in the ultrasonically induced depolymerization of chitosan is evidenced. The first leads to a rapid scission of polymer chains and a lowering of the polydispersity, and the second is responsible for obtaining short polymer chains and oligomers with a polydispersity increase. A systematic experimental study allowed us to identify and quantify the main parameters influencing the chain scission kinetics.