Molecular Dynamics Simulations of Polyamide Membrane, Calcium Alginate Gel, and Their Interactions in Aqueous Solution
Y Xiang and YL Liu and BX Mi and YS Leng, LANGMUIR, 30, 9098-9106 (2014).
We perform molecular dynamics (MD) simulations to investigate the cross- linked polyamide (PA) membrane, the aggregation of alginate molecules in the presence of Ca2+ ions, and their molecular binding mechanism in aqueous, solution. We use a steered molecular dynamics (SMD) approach to simulate the unbinding process between a PA membrane and an alginate gel complex. Simulation results show that Ca2+ ions are strongly associated with the carboxylate groups in alginate molecules, forming a web structure. The adhesion force between alginate gel and PA surface during unbinding originates from several important molecular interactions. These include the short-range hydrogen bonding and van der Waals attraction forces, and the ionic bridge binding that extends much longer pulling distances due to the significant chain deformations of alginate gel and PA membrane.
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