Theoretical analysis for dialysis-induced chitosan gelation

Abstract

The dynamics of dialysis-induced chitosan gel formation has been analyzed by a theory with "moving boundary picture" for the case where the gelation occurs by neutralization. Three datasets for the dependence of concentrations of NaOH in the immersing solution, acetic acid in the solvent and chitosan for the whole range of time fit well to the theoretical equations, by which the validity of the theory was confirmed.

Anisotropic Hydrogel Formation: Effect of Boundary Condition

“…The dynamics of the gel front line is expressed by a universal function using a scaled variables predicted by a theory [1,2], which is based on the assumption of moving sol-gel boundary formed between the layers with and without trapped cross-linking agents. The method was further developed to a simple case where the flow of low molecular weight components through the dialysis membrane modify the state of the polymer molecules, using chitosan solutions [3,4]. When the pH of chitosan solutions becomes to be high, the positive charges of chitosan molecules are neutralized and undergone coacervation-phase inversion, resulting in gelation due to hydrophobic interactions and hydrogen bondings between chain segments [5].…”