Self-assembly behaviors of zwitterionic heterogemini surfactant at an oil-water interface: A dissipative particle dynamics study

The self-assembly behaviors of a battery of zwitterionic heterogemini surfactants CmH2m+1-PO4--(CH2)(2)-N+(CH3)(2)-CnH2n+1, abbreviated as C-m-P-N-C-n (m, n = 9, 9; 9, 12; 9, 15; 9, 18; 12, 12; 12, 15; 12, 18; 15, 15; 15, 18; 18, 18), have been explored at an oil-water interface by means of the dissipative particle dynamics (DPD) method. Regular oil-water contact together with oil-in-water and water-in-oil emulsions has come into being. Compared with the C-m-P-N-C-n concentration and the oil-water ratio, the hydrophobic chain length plays a less important role in the self-assembly morphology of C-m-P-N-C-n molecules at the interface together with the interfacial morphology. The asymmetry in the molecular structure of C-m-P-N-C-n dominates its critical micelle concentration (CMC) and interfacial efficiency. The C-m-P-N-C-n concentration and its hydrophobic chain length work together to affect the interfacial thickness. What's more, the dependence of CMC on the C-m-P-N-C-n molecular structure is in qualitative agreement with corresponding experimental findings. [GRAPHICS] .