The MARTINI force field has become increasingly popular in material science by virtue of its versatility and building block approach. However, parametrization is primarily based on reproducing structural thermodynamic properties the blocks solution, which may not be most suitable strategy for regular, extended surfaces at solid–liquid interfaces, e.g., planar facets nanoparticles. In this study, we propose a novel simulating contact with liquids. While choice bead types models molecules ions...

In this work, we systematically investigate the impact of counterion size on behavior star-shaped strong polyelectrolytes in dilute aqueous solutions using Langevin simulations and a primitive model electrolytes. Varying both diameter number arms polyelectrolyte, demonstrated that characteristics significantly polyelectrolyte conformations counterions absorption. Counterions dynamics is also affected, most interesting aspect being presence fraction mobile ions slowly diffusing, compared to...

Mixing of oppositely charged macromolecules can, under certain conditions, lead to the formation electrostatically cross-linked coacervate gels. In this simulation study, we determine conditions which equimolar mixtures monodisperse four-armed star copolymers with end-blocks are able form such The cationic blocks consist quenched charges, whereas anionic contain pH-responsive weak acid groups. We used Grand-reaction method phase stability, equilibrium composition, and structural properties...

ABSTRACT Absorption of weak polyelectrolytes impacts on properties such as ionization, conformations, and counterion (CI) condensation that are important in several areas applied fundamental science. We used a polyelectrolyte model Monte Carlo simulations to investigate how the mentioned depend pH or size spherical cavity (SC) permeable CIs but not polyelectrolytes; latter have either linear starlike topologies may be allowed form charged hydrogen bonds (cH‐bonds) between ionized neutral...

In this work, we performed titration simulations of weak linear polyelectrolytes via the Monte Carlo method and constant pH ensemble aiming to understand how polyelectrolyte concentration, chain rigidity, formation intra- inter-chain charged hydrogen bonds (c-H-bonds) impact on ionization conformations polyacidic species, counterions (CIs) distribution, system Helmholtz energy. Increasing concentration resulted in enhanced acidity for all cases investigated due increased screening charges by...

The insertion of a pyridine substituent on the lateral chain N-heterocyclic carbene ligands enhances catalytic activity [Ru(CO)2(cyclopentadienone)(NHC)] complexes, precursors Shvo-type catalysts, toward hydrogenation 4-fluoroacetophenone in refluxing 2-propanol as hydrogen donor. DFT calculations evidence role donor/acceptor properties and complexes reactivity both case imidazolylidene triazolylidene ligands. Although NHC-pyridine derived perform somewhat worse than forerunner Shvo dimer,...

The potential performance of porous membranes in separating hydrogen isotopologues has been explored employing model systems and quanto-mechanical calculations including both zero-point energy a numerically exact description tunneling effects along the reaction coordinate. Membranes have modeled as cylindrically pierced impenetrable wall, whereas diatomic molecules are described dumbells composed hard-sphere atoms. With relative energetics diatomics confined into cylindrical pores suggesting...

Solvent evaporation driven self-assembly of Janus nanoparticles (J-NPs) has been simulated employing lattice-gas models to investigate the possible emergence new superlattices. Depending on chemical nature NP faces (hence solvophilicity and relative interaction strength), zebra-like or check-like patterns micellar agglomerates can be obtained. Vesicle-like aggregates produced by micelle-based corrals during heterogeneous evaporation. Patterns formed aggregation appear robust against changes...

We use Langevin dynamics simulations to study the knotting properties of copolyelectrolyte rings carrying neutral segments. show that by solely tuning relative length and charged blocks, one can achieve different combinations knot contour position size. Strikingly, latter is shown vary nonmonotonically with segment; at same time, switches from being pinned block's edge becoming trapped inside it. Model calculations relate both effects competition between two adversarial mechanisms: energy...

Stochastic simulations have been used to investigate the conformational behavior of knotted weak polyacid rings as a function pH. Different from commonly expected ionization–repulsion–expansion scheme upon increasing pH, theoretical results suggest nonmonotonic gyration radius Rg2. Polyelectrolyte recontraction at high ionization is induced by weakening Coulomb repulsion due counterions (CIs) localizing interphase between polymer and solvent, more marked it appears, complex knot topology....

Despite the neutrality of headgroups, polyanions impact on ion distributions inside zwitterionic micelle corona acting as “shuttle” for species with opposite charges. Hydrophilic polyanions, however, do not reduce critical micellar concentration.

A Langevin MD study of an equimolar mixture monodispersed oppositely charged di- block four-armed polyelectrolyte stars is presented. We determine the minimal length which results in gels and we ionic bond kinetics.

The presence of salts in a solution containing weak polyelectrolytes is known to modify both their titration behavior and conformations due electrostatic screening. Instead, little currently about the changes induced by chemically specific interactions (e.g., charged hydrogen bonds, c-H-bonds). To investigate this aspect, we simulated polyacids with primitive model Monte Carlo methods monovalent whose anions are capable forming c-H-bonds associated acid groups. interaction between...

We used Langevin dynamics simulations to study coarse-grained knotted copolyelectrolytes, composed by a neutral and charged segment, in solutions of different salt concentrations, valency, solvent screening power. show that the facile variation these parameters allows for tuning length position region, which turn controls overall metric properties. Specifically, adding either monovalent or divalent ions causes knot swell at expense copolyelectrolyte size. However, typically straddles...

The MARTINI force field has become increasingly popular in material science by virtue of its versatility and building block approach. However, parametrization is primarily based on reproducing structural thermodynamic properties the blocks solution, which may not be most suitable strategy for regular, extended surfaces at solid-liquid interfaces, e.g., planar facets nanoparticles. In this study, we propose a novel parametrizing contact with liquids. While choice bead types models molecules...

Using Langevin dynamics simulations and a coarse-grained primitive model of electrolytes, we show that the behavior knotted circular strong polyelectrolytes (PEs) in diluted aqueous solution is largely affected by diameter counterions (CIs), σCI. Indeed, observe both gyration radius knot length vary nonmonotonically with σCI, small bulky CIs favoring localization, while medium-sized ones promote delocalized knots. We also conformational change from to tight knots occurs via progressive...

In this work, we systematically investigate the impact of counterion size on behavior star-shaped strong polyelectrolytes in dilute aqueous solutions using Langevin simulations and a primitive model electrolytes. Varying both diameter number arms polyelectrolyte, demonstrated that characteristics significantly polyelectrolyte conformations counterions absorption. Counterions dynamics is also affected, most interesting aspect being presence fraction mobile ions slowly diffusing, compared to...

Hydrogen bonds between carboxylic groups of hydrophilic polyacids and anionic moieties in surfactant headgroups may reduce the critical concentration above which surfactants aggregate provided interaction is sufficiently strong. As undissociated acid are needed, reduction should depend on solution pH concentration. Pyrene fluorescence was employed to investigate impact that polyacrylic has two sulfonate containing surfactants, sodium dodecylbenzene lauryl sulfobetaine, as a function polyacid...