Self-Assembly of Symmetric Copolymers in Slits with Inert and Attractive Walls.

Although the behavior of the confined semi-dilute solutions of self-assembling copolymers represents an important topic of basic and applied research, it has eluded the interest of scientists. Extensive series of dissipative particle dynamics simulations have been performed on semi-dilute solutions of AB chains in a selective solvent for A in slits using a DL-MESO simulation package. Simulations of corresponding bulk systems were performed for comparison.

Changes in Ion Concentrations upon the Binding of Short Polyelectrolytes on Phospholipid Bilayers: Computer Study Addressing Interesting Physiological Consequences.

This computer study was inspired by the experimental observation of Y. Qian et al. published in ACS Applied Materials and Interfaces, 2018 that the short positively charged -peptide chains and their oligomeric analogues efficiently suppress severe medical problems caused by antimicrobial drug-resistant bacteria despite them not penetrating the bacterial membrane.

Modeling the Phase Equilibria of Associating Polymers in Porous Media with Respect to Chromatographic Applications.

Associating copolymers self-assemble during their passage through a liquid chromatography (LC) column, and the elution differs from that of common non-associating polymers. This computational study aims at elucidating the mechanism of their unique and intricate chromatographic behavior. We focused on amphiphilic diblock copolymers in selective solvents, performed the Monte Carlo (MC) simulations of their partitioning between a bulk solvent (mobile phase) and a cylindrical pore (stationary phase), and investigated the concentration dependences of the partition coefficient and of other functions describing the phase behavior.

DPD Modelling of the Self- and Co-Assembly of Polymers and Polyelectrolytes in Aqueous Media: Impact on Polymer Science.

This review article is addressed to a broad community of polymer scientists. We outline and analyse the fundamentals of the dissipative particle dynamics (DPD) simulation method from the point of view of polymer physics and review the articles on polymer systems published in approximately the last two decades, focusing on their impact on macromolecular science. Special attention is devoted to polymer and polyelectrolyte self- and co-assembly and self-organisation and to the problems connected with the implementation of explicit electrostatics in DPD numerical machinery.

Phase equilibria and conformational behavior of dendrimers in porous media: Towards chromatographic analysis of dendrimers.

Hypothesis: The intricate entropy-enthalpy interplay of dendrimers confined in pores affects their conformation and retention in the porous stationary phase. This work aims at providing important insights into its impacts on partitioning and chromatographic separation in both size-exclusion chromatography (SEC) and interaction chromatography (IC) regimes.

Simulations: Using Monte Carlo (MC) simulations, we investigated the bulk-pore phase equilibria and the conformational behavior of flexible dendrimers differing in generation, in spacer length and in fraction of modified terminal groups interacting differently with pore walls than the majority building units.

Solubilization of Charged Porphyrins in Interpolyelectrolyte Complexes: A Computer Study.

Using coarse-grained dissipative particle dynamics (DPD) with explicit electrostatics, we performed (i) an extensive series of simulations of the electrostatic co-assembly of asymmetric oppositely charged copolymers composed of one (either positively or negatively charged) polyelectrolyte (PE) block A and one water-soluble block B and (ii) studied the solubilization of positively charged porphyrin derivatives (P+) in the interpolyelectrolyte complex (IPEC) cores of co-assembled nanoparticles. We studied the stoichiometric mixtures of 137 A10+B25 and 137 A10-B25 chains with moderately hydrophobic A blocks (DPD interaction parameter aAS=35) and hydrophilic B blocks (aBS=25) with 10 to 120 P+ added (aPS=39). The P+ interactions with other components were set to match literature information on their limited solubility and aggregation behavior.

Partitioning of polymers between bulk and porous media: Monte Carlo study of the effect of pore size distribution.

In this paper we investigated the partitioning of polymer chains between bulk solvent and porous stationary phase under conditions appropriate for the chromatography under critical conditions (LCCC) close to the critical adsorption point (CAP). We addressed the concentration effect and the thermodynamic effect of pore-size dispersity (PSD) and their impacts on chromatography, i.e.

Pore size effect on the separation of polymers by interaction chromatography. A Monte Carlo study.

When the polymers are studied by interaction chromatography (IC) in porous media, the IC separation mechanism competes with the size-exclusion chromatography (SEC) mechanism and under specific conditions close to the critical adsorption point (CAP), the elution times of monodisperse polymer samples nonmonotonically depend on pore sizes. We performed Monte Carlo (MC) simulations to elucidate this intriguing effect. By analyzing the behavior of self-avoiding and intersecting chains in two-dimensionally (2D)-confining square pores and in 1D-confining slits in good and Θ-solvents, we confirmed that the dimensionality of the confinement, more specifically, pore geometry, controls the chromatographic behavior.

Computer study of the solubilization of polymer chains in polyelectrolyte complex cores of polymeric nanoparticles in aqueous media.

The formation and structure of nanoparticles containing non-polar polymer chains solubilized in interpolyelectrolyte complex (IPC) cores and the partitioning of non-polar chains between bulk solvent and IPC cores were studied by coarse-grained computer simulations. The choice of the model system was inspired by experimental results published by van der Burgh et al. (Langmuir, 2004, 20, 1073-1084).

Adsorption of amphiphilic graft copolymers in solvents selective for the grafts on a lyophobic surface: a coarse-grained simulation study.

The sorption of graft copolymers on surfaces attractive only for the backbone and its effect on the conformational behavior of adsorbed/desorbed chains in solvents good for the grafts and poor for the backbone was studied by coarse-grained computer simulations. It was found that the sorption and conformational behavior are very complex and are results of an intricate interplay of solvent quality (polymer-solvent interactions) and solvent strength (polymer-surface vs. solvent-surface interactions).

The self-assembly of copolymers with one hydrophobic and one polyelectrolyte block in aqueous media: a dissipative particle dynamics study.

The reversible self-assembly of symmetrical block copolymers consisting of one hydrophobic block and one ionizable polyelectrolyte block of the same length has been studied in aqueous solutions by dissipative particle dynamics simulations. In addition to three standard dissipative particle dynamics forces (conservative soft repulsion, dissipative and stochastic forces), explicit interaction between smeared charges on ions and on ionized polymer beads described by the electrostatic potential with appropriately localized charges was taken into account. The self-assembly and properties of formed core-shell micelles were investigated as functions of the degree of ionization for systems differing in the hydrophobicity of the non-ionized polyelectrolyte block and in the compatibility of the polymer blocks.

The electrostatic co-assembly in non-stoichiometric aqueous mixtures of copolymers composed of one neutral water-soluble and one polyelectrolyte (either positively or negatively charged) block: a dissipative particle dynamics study.

The electrostatic co-assembly in non-stoichiometric aqueous mixtures of diblock copolymers composed of a neutral water-soluble block and an either positively or negatively charged polyelectrolyte (PE) block has been studied by dissipative particle dynamics (DPD) simulations. The employed DPD variant includes explicit electrostatics and enables the investigation of the role of small ions in the co-assembly. The properties of core-shell associates containing insoluble interpolyelectrolyte complex cores and protective neutral shells were investigated as functions of the ratio of positive-to-negative charges in the system.

Conformational behavior of comb-like polyelectrolytes in selective solvent: computer simulation study.

In this work, we present molecular dynamics simulations of comb-like polyelectrolytes in selective solvent. The studied polymers have a neutral backbone and polyelectrolyte side chains. The solvent is poor for the backbone and the theta solvent for the side chains.

Polyelectrolyte shells of copolymer micelles in aqueous solutions: a Monte Carlo study.

Multimolecular micelles, formed by polystyrene-block-poly(methacrylic acid) in water, are studied by lattice Monte Carlo method. Electrostatic interactions are calculated in the mean-field approximation by solving the Poisson-Boltzmann equation. The model is parametrized according to available experimental data.