Simulation of the swelling behavior of a pH sensitive hydrogel based on natural polymers chitosan and alginate sulfate
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1university of Kashan
2Kashan university
Abstract
Hydrogels, 3D polymeric network physically respond to any changing in pH values of their surrounding solution. These natural based materials are called pH-sensitive hydrogels that had swollen or de-swollen at different value of pH. These smart hydrogels are useful tools for manufacture of biological materials and drug release systems aiming diseases treatment and improving human health. The swelling behavior of hydrogels can be explained by the Nernst-Plank, Poisson's and the mechanical equations. This behavior is analyzed by simulating these three nonlinear partial differential equations, called the chemo-electro-mechanical equations. In this work, the swelling behavior of the pH-sensitive hydrogel based on chitosan-sodium alginate sulfate was analyzed by using two-dimensional steady state chemo-electro-mechanical equations model in finite element COMSOL multiphysics. The changes in sodium ions concentration, electrical potential distribution, stress distribution and hydrogel swelling were studied in different pH solutions. Also, the effect of different fixed charge density and buffer solution was simulated. It was predicted that while the pH increases, the swelling of the hydrogel increases. It was observed when the simulation results as the fixed charge density of the polymeric network increases the hydrogel's diameter increases too. Also, increase in the Young's modulus of hydrogel and ionic valence value of the buffer solution, will result in lower swelling characteristics
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