Structure Formation during the Synthesis of Chitosan L- and D-Asparaginate Nanoparticles.

Structure formation in the chitosan + L-(D-)aspartic acid + water system during the spontaneous formation of polymer nanoparticles is discussed. The molar electric conductivity of chitosan L-(D-)asparaginate solutions in Kohlrausch coordinates decreases with increasing polymer concentration due to a decrease in the mobility of the ions of the acid residue under the action of the electrostatic potential of the macroion. The concentration dependence of the specific electric conductivity and the hydrodynamic parameters indicate partial compensation of the charges of macrochains through the formation of –anion ion pairs. The discovered tendencies are a complex function of association of counterions with the polycation, leading to phase segregation of the polymer substance at the nanoparticle level. The counterionic condensation effects and the diameter of the formed nanoparticles are largely determined by the [acid] : [~–NH₂] molar ratio and the enantiomeric form of the acid residue. [ABSTRACT FROM AUTHOR]