Adsorption of C5Pe molecules on silica surfaces with different hydrophobicity studied by molecular dynamics simulation

The adsorption of C5Pe molecules on silica surfaces with different hydrophobicity is systematically studied by a series of molecular dynamics simulations. For probing the effect of hydrophobicity of silica surfaces on the adsorption of C5Pe molecules, the properties of the silica surfaces were changed by controlling the ratio of hydrophilic and hydrophobic groups. According to the difference of interface properties, five systems were studied including the fully hydrophilic system, the 25% hydrophobic system, the 50% hydrophobic system, the 75% hydrophobic system and the fully hydrophobic system. We focused on analyzing C5Pe molecules morphology that directly contact with silica surfaces in different systems. Two adsorption configurations, tilted adsorption and tiled adsorption, were first presented in our study. The relationship between adsorption configuration and hydrophobicity was analyzed quantitatively. The results proved that the C5Pe of 25% hydrophobic silica interface prefer to adsorb in the form of tiled configuration and have strongest adsorption stability. Besides, the tiled adsorption C5Pe molecules were found to have better adsorption stability than tilted adsorption C5Pe molecules. And the study of C5Pe transforming from tilted adsorption to tiled adsorption revealed that C5Pe molecules have to surmount two energy barriers in the transforming process. The adsorption process of a tiled adsorption C5Pe molecule was analyzed in the 25% hydrophobic system. (a) two energy barriers in the transformation of adsorption configuration (b) the snapshots of adsorption configuration in different adsorption stages. [Display omitted] •The adsorption of C5Pe molecules on silica surfaces with different hydrophobicity is studied by a series of MD simulations.•Two adsorption configurations, tilted adsorption and tiled adsorption, were first presented in our study.•Comparing with other systems, the 25% hydrophobic oil/solid interface has a stronger adsorption capacity.•In the process of C5Pe transforming from tilted adsorption to tiled adsorption, two energy barriers were first found.