REVERSIBLE THERMOTHICKENING OF AQUEOUS SOLUTIONS OF POLYCATIONS FROM NATURAL ORIGIN

This paper concerns our first set of experimental data on alkyl chitos ans in acidic medium allowing to compare the roles of the degree of al kylation and that of the length of the alkyl chains on their physicoch emical properties in aqueous solution. The balance between electrostat ic repulsion (related to the fraction of -NH3+) and the hydrophobic at traction is discussed on the CC12 sample, a chitosan modified with a C -12 aliphatic chain. A phase diagram is established separating the con ditions for gel-like structure formation and phase separation. The rol es of the net charge and that of the temperature on the formation of h ydrophobic aggregates are examined.