Dresden 2026 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Complex Fluids, Colloids, Micelles and Vesicles I

CPP 30.3: Talk

Tuesday, March 10, 2026, 14:45–15:00, ZEU/0260

Role of acids in stabilizing Reverse Micelles: the case of Dodecyl Sulfate — •Qixuan Li and Marialore Sulpizi — Faculty of Physics and Astronomy, Ruhr-University Bochum

The anionic surfactant Sodium dodecyl sulfate (SDS) can form reverse micelles (RMs) in two non-miscible components above the critical micelle concentration [1]. Although the RMs in salt or alkali solution has been investigated in previous studies [2,3], less is known on the working mechanism of acids in SDS RMs. Here, we employ all-atom (AA) and coarse-grained (CG) molecular dynamics to investigate the effects of chloroauric acid (HAuCl4), fluoroboric acid (HBF4) and phosphoric acid (H3PO4) solutions on the stability of the RMs through spontaneous self-assembly in toluene. We find that investigated acids can stabilize micellar structure, particularly H3PO4 due to the stable hydrogen-bonds it forms with the SDS headgroups. In addition, HAuCl4 can significantly influence micelle shape because of its strong polarizability at the water-toluene interface, while HBF4 causes the highest interfacial tension as a result of its significant hydrophilicity. Moreover, scission free energy calculations from CG simulations [4,5] reveal important differences, which along with the viscosity can explain how different acids affect the size of RMs. Our findings can help to rationalize the impact of different acids on the RMs stability and morphology and, in turn, on the metallic nanoparticles synthesis where the RMs are used as nanoreactors.

Keywords: all-atom molecular dynamics; coarse-grained molecular dynamics; acids; Sodium dodecyl sulfate reverse micelle