Micelle morphology and chain conformation of triblock copolymers under shear: LA-DPD study

Dissipative particle dynamics simulations of tri-block co-polymer and water: Phase diagram validation and microstructure identification

“…[43][44][45] Among its wide range of possible applications, DPD can be used to simulate shear effects on complex fluids due to the peculiarity of preserving hydrodynamic interactions. 2,46,47 In a DPD simulation, interacting beads are representative of clusters of atoms or molecules. The interaction between beads can be described with Langevin dynamics…”

“…50 The DPD parameters used to simulate the polymer chains were obtained from the literature. 2 The level of coarse-graining adopted to describe the Pluronic L64 chains is 4.3 for the EO repeated units and 3.3 for the PO repeated units. This means that one coarse-grained bead of EO contains 4.3 atomistic EO monomers and the same conversion procedure applies for PO.…”

“…1 DPD describes the interaction between beads, representative of clusters of atoms and molecules, using a bead-spring model, repulsive soft potentials combined with stochastic and dissipative forces. Prhashanna et al, 2 Cheng et al, 3 Zhen et al, 5 Cao et al, 4 and Li et al 6 already discussed and validated the reliability of DPD to predict the formation of micelles, at thermodynamic equilibrium, and microstructures in systems composed of water and surfactants. Also, complete phase diagrams can be obtained for ternary compounds as described by Wang et al, Son et al, and Yuan et al [7][8][9] When a mechanical perturbation is applied (like in a mixing tank), shear stresses induce deformation of the microstructure that can lead to phase transitions.…”

“…37,38 Due to their incredibly wide range of applications and their relative simple structure, different Pluronic copolymers, named with different labels based on the length of the repeating units, such as P84, L64, F127, and P123, have been investigated from the computational point of view using DPD under both equilibrium and non-equilibrium simulations. 2,[38][39][40] Shear effects on microstructures can be proved by the change in the apparent viscosity shown by water-surfactant systems at different shear rates as described by Newby et al 13 and Youssry et al, 14 where the rheological properties of Poloxamer 407 in aqueous solutions were investigated. Phase transitions, changes in orientation, deformation, and coalescence of micelles are examples of the phenomena involved when these fluids are subjected to shear.…”

Dissipative Dynamics of Granular Materials

“…For two particles in close proximity, it was reported that the pairwise summation of hydrodynamic forces can be erroneous in estimating the many-body hydrodynamic forces/torques, represented using fourth-order tensors [32]. Interestingly, DPD was widely used to investigate the motion of macromolecules and polymers, which are soft and deformable, in liquid phases [25][26][27][28][29][30][31][33][34][35]. The computational advantages of DPD include that, first, the tensor-wise hydrodynamic interactions are simplified to pairwise forces (although this approach has less fundamental rigor); second, the smooth functional form of Eq.…”