Investigation on the formation and stability of microemulsions with Gemini surfactants: DPD simulation

Abstract

To study the formation and stability of the O/W and reverse W/O microemulsion, dissipative particle dynamics (DPD) simulation was utilized to investigate the system composed of oil, water and Gemini surfactants. The effects of oil-water ratio, temperature, inorganic salt and shear rate were discussed in the simulation. Controlled of the formation process and stability of microemulsions by analyzing the interfacial tension of oil and water interfaces, end-to-end distance of Gemini surfactants and the translucent three-dimensional structures of formed aggregates. Two types microemulsions could form and mutually transform with changing the oil-water ratio. In conclusion, the O/W microemulsion has better temperature, salt and shear tolerance comparing to the reverse W/O microemulsion. The results of the research using DPD simulation expanded the theoretical knowledge of microemulsion on the molecular level, which is of great importance to develop new microemulsion systems with other surfactants and provided better theoretical guidance for the application of microemulsions.

Graphical abstract

The O/W and W/O microemulsion could formed and transformed by changing the oil-water ratio (from 1:5 to .5:1) at same external conditions(a). Besides, the O/W Microemulsion has a better stabitity with changing inorganic salt, temperature and shear(b).

Keywords:

• Microemulsion
• dissipative particle dynamics simulation
• interfacial tension
• end to end distance

Additional information

Funding

The work was financially supported by the Innovation Foundation Project [BZXYG1617], the Key Technology Research and Development Program of Shandong Province under Grant [2019GSF109117], Shandong Natural Science Foundation of China [ZR2020MB032], and the PhD Start-up Fund of Binzhou university[2018Y20].