Dissipative particle dynamics simulations reveal the pH-driven micellar transition pathway of monorhamnolipids.

Dissipative particle dynamics (DPD) simulation has been used to study the effect of pH on the morphology transition of micelles assembled by monorhamnolipids (monoRLs). Results show that micellar structures and transition modes with increasing mass concentrations are multiform due to the changeable hydrophilicity of pH-responsive beads at different pH levels. Various chaotic multilayer aggregations of monoRLs are observed at low pH (pH<4.0) whereas well-ordered single-layer structures are obtained at high pH (pH>7.4). At medium pH region (4.0<pH<7.4), morphologies with semi-chaotic structures will transform from multilayer to single layer with increasing pH due to the hydrophilicity increase of micelles. In addition, three micellar transition modes are built by varying the hydrophilicity of pH-responsive beads and validated by solvent accessible surface areas (SASAs) as a function of mass concentrations. This work is expected to trigger further studies on the stimuli-driven phenomena of glycolipids.