Molecular dynamic simulation study on formation of water channel in oil film detachment process controlled by surfactant polarity

Adopting molecular dynamic simulations method, four kinds of surfactant with different head groups and same alkyl chain, sodium dodecyl sulfonate (SDSn), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium dodecyl-dioxyethylene ether sulfate (AES) were employed to study the polarity effect on oil film detachment from silica surface. Our results indicates that the formation of water channel is crucial for oil film detachment and was discussed in detail, and the size of water channel is adopted to evaluate the detachment of oil film. Our simulation results indicated that the stronger the surfactant polarity is, the easier the water channels form, and gave the order of oil detachment capability: AES > SDBS > SDS > SDSn. Our study is helpful to deeply understand the oil film detachment behavior and the polarity effect from molecular and atomic insight.

Automated summary

Using molecular dynamic simulations, this study investigated the polarity effect of different surfactants on oil film detachment from silica surfaces. The results showed that the formation of water channels is crucial for oil film detachment, and the strength of surfactant polarity determines the ease of water channel formation, affecting the detachment capability of the oil film. Through molecular and atomic insights, this study provides a better understanding of the behavior of oil film detachment.