I am using chitosan having DDA above 90% & average mol Wt. 100000 - 300000.I have tried to dissolve it in acetic acid & trifloro acetic acid bur problem is i can able to make solution up to 2% but above it solution is becoming so thick like gel please give me some suggestion.Please suggest me solvent which can make 10% chitosan solution.
The problem isn't so much with your solvent as it is with your chitosan. Chitosan of high-MW will exhibit high viscosity in almost any solvent, so there is a practical limit to how much you can dissolve before the viscosity becomes too high, as you have discovered. If you heat the TFA solution, I'm sure more will dissolve and the viscosity will decrease, but that will be due to acid hydrolysis of the chitosan's glycosidic bonds. You will end up with a solution of glucosamine and low-MW chito-oligosaccharides. The only way around your problem will be to use lower-MW chitosan, or settle for the 2% solution you have.
Dear Santosh
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 be dissolve 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)
I agree with all the responses above. Because of the high MW of the chitosan you are using, you may need to settle with the 2% or lower concentration of chitosan and make changes with your protocols instead. The properties of the chitosan you are using will not change but you ca adjust your procedure for your studies.
Can someone tell me please for 9% of chitosane hydrogel , the acetic acid concentration that we need ?
Thanks .
Does anyone know how to make chitosan 2 wt% by mixing the chitosan powder with acetic acid? Your reply is precious. Thanks
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