Dear Bachir

Chitosan is not soluble in aqueous or alkali solvents and it is soluble in acidic solvents like glacial acetic acid & diluted acids like HCL, H2O2, H2SO4 and HNO3.

Moreover, Chitosan is a polymer with hydroxide and amine groups so in order to make it (more) soluble in water one needs to either deprotonate OH groups or protonate NH2. It is easier (less damagin to the polymer) to protonate amines to NH3(+). Their pKa is close to 7 so mild acidic solution will do (final solution pH close to 4). Since they are charged in water they will move toward electrode or a charged wall. And, plan your experiment so once it is disolved, keep it wet until done with the experiment.

As Chitosan can also be dissolved in acidic sovents. You can use any of the two methods

1. Chitosan can also be dissolved in the mixture of 0.1M Acetic acid and 0.2M NaCl (at Room temp., 12 Hours with stirring) ............OR...............

2. Chitosan can be dissolved in 0.1M acetic acid (at 60 degrees Celcius ., 5 hrs with stirring)