(376bg) Modelling Micellization of Rhamnolipid Biosurfactant By Mesoscale Simulation

The sustainability movement has
been driving a desire to replace petroleum surfactants by biodegradable ones in
many chemical industries. Designing eco-friendly products requires fundamental
understandings of surfactant micellization at the molecular level. The present
work aims to predict the self-assembling and micellar properties of rhamnolipid
biosurfactants using mesoscale dissipative particle dynamics (DPD) simulations.
A coarse-graining technique is developed here to address the issue of modeling
molecules with complex structure by equal-sized DPD beads. The Rhamnolipid is
dissected into coarse-grained particles of various diameters determined by the
Connolly volume of their composing functional groups. “Linkers” are introduced
to maintain the molecular structure by mimicking the conformations at the
atomistic level. Nonbonded interaction parameters are sampled by particle
insertion method and mapped to the activity coefficient of bead components. The
devised framework preserves the efficiency and the simplicity of common DPD
models, and improves the accuracy in describing chemical specifics resulting in
more precise predictions for the micellization phenomena. The method is applied
to systematically study rhamnolipids with different numbers of head and tail, as
well as varied length of the tails (Rha-Cx-Cy, x & y = 8~16). Results obtained by simulations are
envisioned to provide useful guidelines for future product design in broad
industrial applications.