Mesoscopic Simulations of Adsorption and Association of PEO-PPO-PEO Triblock Copolymers on a Hydrophobic Surface: From Mushroom Hemisphere to Rectangle Brush

Abstract

The dissipative particle dynamics (DPD) method is used to investigate the adsorption behavior of PEO-PPO-PEO triblock copolymers at the liquid/solid interface. The effect of molecular architecture on the self-assembled monolayer adsorption of PEO-PPO-PEO triblock copolymers on hydrophobic surfaces is elucidated by the adsorption process, film properties, and adsorption morphologies. The adsorption thicknesses on hydrophobic surfaces and the diffusion coefficient as well as the aggregation number of Pluronic copolymers in aqueous solution observed in our simulations agree well with previous experimental and numerical observations. The radial distribution function revealed that the ability of self-assembly on hydrophobic surfaces is P123 > P84 > L64 > P105 > F127, which increased with the EO ratio of the Pluronic copolymers. Moreover, the shape parameter and the degree of anisotropy increase with increasing molecular weight and mole ratio of PO of the Pluronic copolymers. Depending on the conformation of different Pluronic copolymers, the morphology transition of three regimes on hydrophobic surfaces is present: mushroom or hemisphere, progressively semiellipsoid, and rectangle brush regimes induced by decreasing molecular weight and mole ratio of EO of Pluronic copolymers.

Mesoscopic probes in asphaltenes nanoaggregate structure: from perpendicular to paralleled orientation at the water-in-oil emulsions interface

“…In dynamic simulation processes, an order parameter could be monitored to indicate the changes occurring in the molecular structures, and could thus yielded characteristics of the phase separation and compressibility. The order parameter (P), which was the mean squared deviation from homogeneity for a particular species (A) in volume V, was dened as: 46,47 where h 0 A was the overall volume fraction of species A, and h A was the local volume fraction of species A; note that both quantities were dimensionless in DPD simulations. Therefore, small values for P A indicated a homogeneous system, and large values suggested strong phase separation.…”

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

“…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 particle dynamics investigation of demulsification process and mechanism of comb‐like block polyether

“… In this paper, same integration algorithm are used as Groot and Warren to calculate weight functions and parameters On the other hand, dimensionless qualities are used in this work, and r c , kT , and m represent the unit length, unit energy, and mass of a DPD bead, respectively.…”