Effects of Polar Fractions Effect on Interfacial Phenomena at the Hydrophobic /Carbonated Aqueous Solution Interface

This study utilized molecular dynamics simulations to understand the liquid/liquid interfaces in a complex natural environment involving various gases , ions, and acidic/basic components. The aim was to investigate the impact of polar fractions, such as benzoic acid, decanoic acid, phenol, and decanol, on the interfacial phenomena of the hydrophobic phase (Decane) and water/CO2-rich water at a molecular level. The findings indicate that carbon dioxide molecules gather at the decane/water interface before moving toward the oleic phase. When polar molecules are introduced to the hydrophobic phase, there is competition between carbon dioxide and acidic components to accumulate at the interface. The functional hydrocarbon fractions displace carbon dioxide at the interface and bridge the hydrophobic and hydrophilic phases, reducing interfacial tension. The presence of polar components causes changes in the charge distribution of water molecules in the biphasic system, suggesting that the organized water layer at the interface with the non-aqueous phase has been disrupted. Among the functional fractions, benzoic acids are the only fractions that exhibit attractive electrostatic affinity to each other due to their π-π interaction, whereas other functional fractions display repulsive electrostatic interactions. However, the strong attraction of benzoic acids has no significant impact on interfacial tension. Furthermore, the polar fractions presented do not impede the diffusion of CO2 from the aqueous phase to the oleic phase, but they reduce their movement rate . Accordingly, the fluidity of Decane exhibited significant enhancement by CO2 dispersion throughout the bulk oil phase, leading to substantial viscosity improvement .