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1

Dendrimers vs. Hyperbranched Polymers: Studies of the Polymerization Process Based on Monte Carlo Simulations

Polanowski Piotr, Hałagan Krzysztof, Sikorski Andrzej

Computational Methods in Science and Technology

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2022

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Vol. 28, No. 3

109--117

EN

A simple model was developed for studies of the polymerization process of branched polymers. Monte Carlo simulations were carried out by means of the Dynamic Lattice Liquid algorithm. A living polymerization in bulk of dendrimers and hyperbranched polymers was studied. The mass and structure of both types of macromolecules were investigated. The influence of the functionality of well-defined cores on the structure of the system was also examined. The differences in the kinetics in the formation of both architectures and changes to their structures were discussed. It was shown that both architecture exhibit low dispersity which was found to be higher for hyperbranched macromolecules.

2

Computer Simulation of the Dynamic Behavior of Double Polymer Brush-Solvent Systems

Hałagan K., Banaszak M., Jung J., Polanowski P., Sikorski A.

Computational Methods in Science and Technology

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2021

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Vol. 27, No. 4

141--149

EN

Opposing polymer brush systems were investigated by computer simulations. In a coarse-grained model, chains were restricted to a face-centered cubic lattice with the excluded volume interactions only. The macromolecules were grafted onto two parallel impenetrable surfaces. The dynamic properties of these systems were studied by means of Monte Carlo simulations. The Dynamic Lattice Liquid model and a highly efficient parallel machine ARUZ were employed, which enabled studying large systems at long time scales. The influence of the surface grating density on the system dynamic was shown and discussed. It was demonstrated that the self-diffusion coefficient of solvent depended strongly on the grafting density.

3

The influence of temperature on the percolation threshold in two-dimensional polymer systems

Sikorski A.

Computational Methods in Science and Technology

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2020

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Vol. 26, No. 4

143--149

EN

The structure of a two-dimensional film formed by strongly adsorbed polymer chains was studied by means of Monte Carlo simulations. We investigated the percolation in systems consisting of flexible polymer chains. A coarse-grained polymer chains representation was assumed and polymer chains were represented by linear sequences of lattice beads. The positions of these beads were restricted to vertices of a two-dimensional square lattice. Properties of the model system were determined by means of Monte Carlo simulations with a refined Verdier-Stockmayer sampling algorithm. Percolation thresholds macromolecules were determined. The methodology concerning the determination of the percolation thresholds for an infinite chain system was discussed. The influence of the chain length and the temperature on the percolation was discussed. It was shown that the introduction of long-range interactions changes the behavior of the percolation threshold dramatically. The percolation threshold initially decreases with the chain length while for longer ones it is stable.

4

Computer Simulation of Cyclic Polymers in Disordered Media

Kuriata A., Sikorski A.

Computational Methods in Science and Technology

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2015

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Vol. 21, No. 1

21--27

EN

In order to determine the structure and dynamical properties of cyclic polymers (rings) in a random environment we developed and studied an idealized model. All atomic details were suppressed, chains were represented as a sequence of identical beads and were embedded to a simple cubic lattice. A set of obstacles was also randomly introduced into the system and it can be viewed as a model of porous media. A Monte Carlo sampling algorithm using local changes of chain conformation was used to sample the conformational space. It was shown that the mean dimensions of the chain changed with the concentration of obstacles but these changes were non-monotonic. The long-time (diffusion) dynamic properties of the system were also studied. The differences in the mobility of chains depending on the obstacle density were shown and discussed.

5

Motion of Star-Branched Chains in a Nanochannel. A Monte Carlo Study

Romiszowski P., Sikorski A.

Computational Methods in Science and Technology

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2012

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Vol. 18, No. 1

39-44

EN

In order to determine the structure and dynamic properties of polymers systems in a random environment we developed and studied an idealized model. Properties of the model of confined linear and branched polymer chains were studied by means of the Monte Carlo method. Model chains were built of statistical segments and embedded to a simple cubic lattice. Then, the polymers were put into a tube formed by four impenetrable surfaces. A Metropolis-like sampling Monte Carlo algorithm was used to determine the static and dynamic properties of these model macromolecules. The influence of the size of the confinement (the tube diameter) and the chain length on polymer properties was studied. The universal behavior of confined polymer linear chains under consideration was found and discussed. The long-time (diffusion) dynamic properties of the system were also studied. The differences in the mobility of chains depending on the number of branches was shown and discussed – stars with an even number of arms exhibited the ballistic motion at certain conditions. The possible mechanism of the chain' motion was discussed.

6

The influence of the macromolecular architecture on adsorption of polymer chains on a solid surface

Adamczyk P., Sikorski A.

Polimery

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2010

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T. 55, nr 7-8

512-517

EN

Computer simulations of a simple model of adsorbed polymer chains were performed with the dynamic Monte Carlo method. The coarse grained chain representation was used and model macromolecules were confined to vertices of a simple cubic lattice. The chains were modeled with excluded volume only, i.e. at good solvent conditions. The polymers interacted with an impenetrable surface via an attractive potential, which was varied to cover both weak and strong adsorption regimes. Three different chain architectures were studied: linear and star-branched with three and four arms. It was found that size of chains obeys the scaling law with exponential characteristics for two- and three-dimensions for the weak and strong adsorption regime respectively. The transition temperatures between these regimes were also determined. The structure of adsorbed polymers was found similar for all architectures especially for the case of strong adsorption.

PL

Za pomocą symulacji komputerowej metodą Monte Carlo (wykorzystano algorytm Yerdiera-Stockmayera) przeprowadzono badania właściwości zaadsorbowanych łańcuchów polimerowych. Makrocząsteczki modelowano korzystając z uproszczonych modeli, w których rzeczywisty nieprzecinający się łańcuch był przybliżony sekwencją jednakowych segmentów. Założono, że modelowe łańcuchy tworzą pseudo-krystaliczną sieć regularną. Polimery umieszczono w szczelinie, której ściany oddziałują potencjałem przyciągającym na segmenty łańcucha. Zbadano trzy modele makrocząsteczek o różnej architekturze wewnętrznej: łańcuchy liniowe oraz gwiaździście rozgałęzione zawierające 3 lub 4 ramiona. Zbadano wpływ podstawowych parametrów układu na strukturę zaadsorbowanych łańcuchów. Wykazano, że łańcuchy w temperaturach wyższych (słaba adsorpcja) skalują się jak trójwymiarowe, a w niższych (silna adsorpcja) jak dwuwymiarowe, i to niezależnie od architektury łańcucha. Wyznaczono parametry przejścia słaba adsorpcja → silna adsorpcja oraz pokazano, że zwłaszcza w przypadku silnej adsorpcji, struktura zaadsorbowanej warstwy polimerowej słabo zależy od architektury łańcucha.