Lattice Boltzmann simulation of swelling behavior of cylindrical IPN hydrogel tablets

Abstract

This manuscript presents a computational method based on a multiple-relaxation-time lattice Boltzmann method to simulate the swelling behavior of cylindrical IPN hydrogel tablets in contact with buffer solutions at different pH and temperature conditions. The simulations were performed by a lattice Bolztmann model for axisymmetric mass diffusion equation using dimensionless measurements of length and mass; therefore, the mass sample estimation at each time step was not linked to the volume of the tablet. Adsorption isotherm tests were carried out using two IPN hydrogel formulations and copolymeric hydrogel formulation at temperatures equal to 298.15 K (25 °C) and 310.15 K (37 °C) and pH equal to 7.49, 4.72 and 8.22. The results show the reliability of the computational model by reproducing with high accuracy the experimental behavior of the hydrogel swelling process. The temperature and pH effect on equilibrium diffusion coefficient was also investigated by the variations on equilibrium diffusion coefficient. According with the state-of-the-art presented in this paper, the literature does not report the use of LBM to simulate this phenomenon in three-dimensional hydrogels; and neither reports were found related IPN hydrogels, nor varying the pH and temperature conditions which modify the diffusion processes.