An extension to the P3M algorithm for electrostatic interactions is presented that allows efficiently compute dipolar in periodic boundary conditions. Theoretical estimates root-mean-square error of forces, torques, and energy are derived. The applicability tested confirmed several numerical examples. A comparison computational performance new a standard dipolar-Ewald summation methods shows crossover from Ewald method as few 300 particles. In larger systems, represents substantial...

We introduce a regularization procedure to define electrostatic energies and forces in slab system of thickness h that is periodic two dimensions carries net charge. The corresponds neutralization the by charged walls can be viewed as extension two-dimensional (2D)+h geometry homogeneous background standard three-dimensional Ewald method. computed efficiently using advanced methods for systems with 2D periodicity, such MMM2D or P3M/ELC, introducing simple background-charge correction...

We demonstrate explicitly how the two seemingly different particle mesh Ewald methods, smooth (SPME) and particle-particle (P3M), can be mathematically transformed into each other. This allows us in particular to convert error estimate of P3M method energy-conserving scheme (also known as "P3M with analytic differentiation") an for SPME method, via a simple change lattice Green function. Our is valid any values parameters (mesh size, spline interpolation order, splitting parameter,...

In the past decades, ferrofluids have become relevant in many applications ranging from engineering to medicine, and attracted interest of scientists fields. To understand physical mechanisms serving as a basis for these applications, over last properties been studied can now be controlled. However, order fine-tune various aspects interactions system hopefully – long run build tailored structures, recent years, magnetic nanoparticles colloids that deviate model spherical particle with dipole...

Langevin Dynamics numerical simulations have been used to compute the force profiles that dipolar polymer brushes exert onto a penetrating colloidal particle. It has observed are strongly influenced by externally applied fields: at large distances from grafting surface, barrier appears, and shorter region with lower repulsive forces develops. Furthermore, right combination of density, chain length strength external field, it is possible observe in this intermediate both existence net...

We try to elucidate the microstructure formation in a monodisperse ferrofluid monolayer. The system under study consists of soft sphere magnetic dipolar particles confined thin fluid layer. positions are constrained 2D geometry, whereas particle dipole moments not fixed body systems, and free rotate 3 dimensions, hence forming what we call quasi-2D geometry. Using combination analytical density functional theory molecular dynamics (MD) simulations, find that for studied range parameters...

We will review the sparse attempts to model structure and dynamics of polyelectrolyte multilayers with coarse-grained bead–spring models within a continuum solvent approach. Due inherent complexity size system an all-atom modelling approach is not feasible. Even coarse-grain face serious problems in reproducing many experimental observations such as stability under parameter combinations, linear film growth aqueous solutions. current models, point out their shortcomings, discuss possible extensions.

Explicit solvent all-atom molecular dynamics simulations of mixtures poly(styrenesulfonate)(PSS) and poly(diallyldimethylammonium) (PDADMA) polyelectrolytes at various salt (NaCl) concentrations are performed. We characterize the formed polyelectrolyte complexes (PECs) relate observed physical properties PSS−PDADMA PECs to found in multilayers (PEMs) made same compositions. Our results reveal a change way charges compensated upon addition salt, namely from an intrinsic mechanism (polyanions...

In order to investigate the peculiarities of aggregation processes in ferrofluids a quasi-2D geometry, combination density functional theory (DFT) and molecular dynamics (MD) simulations is presented. The microstructure formation monodisperse ferrofluid monolayers studied thoroughly through comparison theoretical computational results. Theoretical simulation results show similar trends which renders approach useful tool for getting insight into monolayers.

Extensive two-dimensional Langevin dynamics simulations are used to determine the effect of steady shear flows on crystal nucleation kinetics charge stabilized colloids and whose pair potential possess an attractive shallow well a few k_{B}T 's (attractive colloids). Results show that in both types systems small amounts speeds up crystallization process enhances quality growing significantly. Moderate rates, other hand, destroy ordering system. The very high rate regime where reentering...

We present a theoretical model for calculating the structure factor ferrofluids with strong inter-particle magnetic dipole–dipole interactions, where chain aggregates are known to exist. Our analytical is based on minimization of free energy density functional that allows us explicitly construct radial distribution functions ferroparticles. Both mono- and bi-disperse systems have been investigated in absence an external field. perform extensive comparison predictions results molecular...

A theoretical formalism to predict the structure factors observed in dipolar soft-sphere fluids based on a virial expansion of radial distribution function is presented. The theory able account for cases with and without externally applied magnetic fields. thorough comparison results molecular-dynamics simulations shows good agreement between numerical when fraction particles involved clustering low; i.e., coupling parameter $\ensuremath{\lambda}\ensuremath{\lesssim}2$, volume...

Extensive all-atom molecular dynamics simulations have been performed to investigate the effect of surface features on adsorption poly(styrenesulfonate) (PSS) oligomers top a modified graphite substrate. In particular, we investigated hydrophilic and hydrophobic model surfaces, accompanied by variable charge density σs in range 0−0.164 C/m2. Our results demonstrate that short-range interactions originating from adsorbing substrate play significant role layer structure adsorbed PSS, they...

We study the equilibrium morphologies of a single supramolecular magnetic filament in three-dimensional system as function effective strength dipolar interactions. The is performed by means Langevin dynamics simulations with bead-spring chain model freely rotating dipoles. demonstrate existence three structural regimes value coupling parameter increased: coil compaction regime, expansion regime and closed which structures tend progressively to an ideal ring configuration. discuss governing...

The equilibrium conformations of a flexible permanent magnetic filament that consists sequence linked colloidal nanoparticles with short-ranged Lennard-Jones attractive interactions (Stockmayer polymer) are thoroughly analysed via Langevin dynamics simulations. A tentative phase diagram is presented for chain length N = 100. exhibits several unusual conformational phases when compared to non-magnetic chains. These characterised by large degree anisotropy, and consist closed chains,...

The equilibrium structure of supramolecular magnetic filament brushes is analyzed at two different scales. First, we study the density and height distributions for with various grafting densities chain lengths. We use Langevin dynamics simulations a bead–spring model that takes into account cross-links between surface ferromagnetic particles, whose magnetization characterized by point dipole. Magnetic are shown to be more compact near substrate than nonmagnetic ones, bimodal distribution...

We theoretically show how the crosslinking mechanism of colloids can drastically change magnetic response supramolecular filaments.

We present results from a detailed numerical study of the kinetics phase transformations in model two-dimensional depletion-driven colloidal system. Transition single, dispersed to two-phase coexistence monomers and clusters is obtained as depth interaction potential among particles changed. Increasing well further, fractal are observed simulation. These have hybrid structure sense that they show hexagonal closed-packed crystalline ordering at short length scales ramified nature larger...

We present results from extensive Monte Carlo simulations of flexible and semiflexible excluded-volume polymer chains confined to impenetrable spherical surfaces. Our are compared with the theoretical predictions for ideal by Mondescu Muthukumar (MM) (Phys. Rev. E 1998, 57, 4411) Spakowitz Wang (SW) Lett. 2003, 91, 166102), respectively. The SW prediction is found be in better agreement our simulation than MM all cases studied. Conformation length L persistence lp restricted move on a sphere...

We optimize Hockney and Eastwood's Particle-Particle Particle-Mesh (P3M) algorithm to achieve maximal accuracy in the electrostatic energies (instead of forces) 3D periodic charged systems. To this end we construct an optimal influence function that minimizes RMS errors energies. As a by-product derive new real-space cut-off correction term, give transparent derivation systematic terms Madelung energies, provide accurate analytical estimate for error This is useful indicator computed allows...

We study the self-assembly of colloidal magnetic particles permanently cross-linked into polymer-like structures with different topologies, that we call supracolloidal polymers (SMPs). In order to understand influence interparticle permanent links, investigate SMPs holding main topologies observed in non-cross-linked via grand canonical Monte Carlo simulations: chains, rings and simple branched structures. Here, using molecular dynamics simulations, focus on systems SMP pairs. Our results...

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant proliferative disorder that may progress to multiple myeloma, malignant plasma cell neoplasia. We evaluated differential scanning calorimetry (DSC) as an experimental tool for differentiating serum samples MGUS patients from healthy individuals. DSC thermograms can be used monitoring changes in the proteome associated with MGUS. showed great variability thermogram characteristics, which depended on IgG, IgA or IgM...

The presence of an external magnetic field enables the existence bistable and multi-stable regions in phase diagram filaments.

We present the results of extensive three-dimensional off-lattice Monte Carlo simulations two interacting spherical brushes. have measured force in systems where curvature effects are important. Our support a description profile divided into regimes. At short separating distances between brushes is well described by theory Witten and Pincus, whereas at larger interaction reproduced extending Flory for dilute polymer solutions. The overall behavior also compared with predictions...