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Adsorption of bovine serum albumin (BSA) on poly(vinylidene fluoride) (PVDF) surfaces in an aqueous environment was investigated in the presence and absence of excess ions using molecular dynamics simulations. The adsorption process involved diffusion of protein to the surface and dehydration of surface-protein interactions, followed by adsorption and denaturation. Although adsorption of BSA on PVDF surface was observed in the absence of excess ions, denaturation of BSA was not observed during the simulation (1 μs). Basic and acidic amino acids of BSA were found to be directly interacting with PVDF surface. Simulation in a 0.1 M NaCl solution showed delayed adsorption of BSA on PVDF surfaces in the presence of excess ions, with BSA not observed in close proximity to PVDF surface within 700 ns. Adsorption of Cl on PVDF surface increased its negative charge, which repelled negatively charged BSA, thereby delaying the adsorption process. These results will be helpful for understanding membrane fouling phenomena in polymeric membranes, and fundamental advancements in these areas will lead to a new generation of membrane materials with improved antifouling properties and reduced energy demands.

Global warming is occurring because of emission of greenhouse gases due to human activities. Capture of CO2 from fossil-fuel industries and absorption of CO2 for natural gas sweetening are crucial industrial tasks to address the threat from greenhouse gases. Amino acid ionic liquids (AAILs) are used for reversible CO2 capture. In this study, the effect of CO2 chemisorption on tetramethylammonium glycinate ([N1111]­[GLY]), tetrabutylammonium glycinate ([N4444]­[GLY]), and 1,1,1-trimethylhydrazinium glycinate ([aN111]­[GLY]) were analyzed using density functional theory (DFT) and molecular dynamics (MD) studies. Density functional theory studies predicted different reaction pathways for CO2 absorption on [GLY]− and [aN111]+. The activation energy barriers for CO2 absorption on [GLY]− and [aN111]+ are 52.43 and 64.40 kJ/mol, respectively. The MD results were useful for mimicking the reaction mechanism for CO2 absorption on AAILs and its effect on physical properties such as the fractional free volume, diffusion coefficient, and hydrogen bonding. Dry and wet conditions were compared to identify factors contributing to CO2 solubility and selectivity at room temperature and elevated temperature. Hydrogen bonding between ion pairs was used to understand the increase in viscosity after CO2 absorption. The MD studies revealed that glycinate and related products after CO2 absorption contribute the most to the increase in viscosity.