In this work the microstructures of star acrylated poly(ethylene
glycol-co-lactide) (SPELA) with different LA:EG ratios in the aqueous
solution have been simulated via Dissipative Particle Dynamics (DPD)
approach at the mesoscale. The system components were coarse-grained into
different beads (set of atoms) which moved according to the Newton’s
equations of motion integrated via a modified Velocity-Verlet algorithm. The
force acting on each bead, in a specific cutoff distance (rc),
was divided into a conservative force (FC), random force (FR), dissipative
force (FD), bond force (FS) and bond angle force (FE). The repulsion
parameters of the conservative force (αij) were calculated from
the solubility parameter of the beads, each of which were extracted from an
atomistic molecular dynamics simulation (MD). Simulations showed the
formation of micelles with lactide and acrylate beads occupied the core and
hydrophilic ethylene oxide segments extending through the water to form the
corona. The micelles showed an increasing trend in size and decreasing trend
in number density with increase in LA:EG ratio. Results showed that the
acrylate density decreased from the center of the micelles to the core
surface although the overall amount of acrylates increased due to the
increase in volume. Furthermore, the running integration number of
acrylate-water beads showed decreasing accessibility of acrylates to water
with increasing PLA volume fraction.