Study on the microstructure and self-assembly of the microemulsion collector for coal slime flotation

[Display omitted] •The interaction parameter between beads in the BGF/n-pentanol/dodecane/water system is established using the Blends method.•The self-assembly, interface, and microstructure of the microemulsion collector are studied by dissipative particle dynamics.•The polar groups of BGF are close to the water in the system, and the non-polar groups tend to be immersed in the dodecane.•N-pentanol molecules fill in the gaps between BGF in the dodecane-water interface. The formation process of microemulsion collectors for coal slime flotation and the underlying mechanisms governing their structure-related interfacial properties are challenging to observe visually by experiments. Dissipative particle dynamics (DPD) technology is employed to investigate the self-assembly process, interface formation, and microstructure of the microemulsion collector, which helps understand the microcosmic formation mechanism of microemulsion collectors and enriches the fundamental theory. The interaction parameter among the beads in the coarse-grained models of dodecane, water, n-pentanol, and BGF molecules was calculated utilizing the Blends method, and the DPD force field for the BGF/n-pentanol/dodecane/water (B-P-DW) system was established. The structure studies showed that the structural type of B-P-DW system transitions from water-in-oil (W/O) to bicontinuous (B.C.), and subsequently to oil-in-water (O/W) with the increase of water content. The self-assembly process of microemulsion collectors showed that the molecules within the B-P-DW system collided and aggregated with increasing simulation time. Specifically, water (or dodecane) molecules formed a rounded or rod-like structure dispersed phase, and dodecane (or water) molecules aggregated to form the continuous phase. Microstructure analyses revealed that BGF molecules exhibit preferential orientation upon adsorption at the oil–water interface within B-P-DW system. Specifically, the polar groups positioned proximal to the water, while the non-polar groups were predominantly immersed in the dodecane. Additionally, the interstitial spaces between BGF molecules were occupied by n-pentanol molecules.