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1
Content available remote 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.
2
Content available remote Monte Carlo Study of Triblock Self-Assembly by Cooperative Motion Algorithm
Wołoszczuk S., Banaszak M.
Computational Methods in Science and Technology
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2020
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Vol. 26, No. 3
89--95
EN
We perform a comprehensive Monte Carlo study of the ABA triblock self-assembly by the Cooperative Motion Algorithm. Our attention is focused on three series of triblocks which are grown from parent AB diblocks of varying asymmetry. Unlike the previous studies in which the total length of the chain varies upon growing the terminal A-block, here we keep the fixed chain length for a given series. Moreover, we determine the order-disorder transition temperature as the τ parameter (being the ratio of the grown A-block to the length of the parent diblock) increases. In this case we find that the order-disorder transition temperature monotonically decreases for two asymmetric series which is different from the non-monotonic depression of TODT reported previously. We also construct a phase diagram which shows a variety of nanostructures as τ is increased.
3
Content available remote Dual Self-Assembly in Strongly Asymmetric A-B-A Triblock Copolymer Melts Studied by Self-Consistent Field Theory and Monte Carlo Simulations
Dzięcielski L., Wołoszczuk S., Banaszak M.
Computational Methods in Science and Technology
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2018
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Vol. 24, No. 4
227--234
EN
Using the Self-Consistent Field Theory (SCFT) we study the dual self-assembly of ABA triblock copolymers melts and compare the numerical results with those obtained by the lattice Monte Carlo simulations. While the results are qualitatively similar for both methods, the simulation times are significantly shorter for the SCFT calculations than those for the corresponding Monte Carlo simulations
4
Content available remote Simulation of Ionic Copolymers by Molecular Dynamics
Dzięcielski M., Knychała P., Banaszak M.
Computational Methods in Science and Technology
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2016
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Vol. 22, No. 4
187--196
EN
Using GROMACS (a molecular dynamics package) we simulate ionic copolymers and compare the numerical results with those obtained by the lattice Monte Carlo simulations. While the results are qualitatively similar for both methods, the simulation times are significantly longer for the molecular dynamics simulations than those for the corresponding Monte Carlo runs
5
Content available remote Monte Carlo simulations and self-consistent field theory applied to calculations of density profiles in A1BA2 triblock copolymer melts
Dzięcielski M., Wołoszczuk S., Banaszak M.
Polimery
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2014
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T. 59, nr 7-8
580--584
EN
Using two complementary numerical methods, the lattice Monte Carlo simulations with parallel tempering and self-consistent field theory, we investigate the distribution of A1, B, and A2 segments in the lamellar nanostructure of A1BA2 triblock copolymer melts. While the lattice Monte Carlo method is in principle exact, it is limited by a variety of factors, such as finite size effects, long relaxation times required to reach the thermal equilibrium and geometry of the underlying lattice. It is also limited to chains consisting of relatively few segments. The self-consistent field theory, on the other hand, is free of the above limitations, but it is a mean-field approach which does not take into account the thermal fluctuations. Therefore we confront the results obtained from the two above methods and draw conclusions concerning both the comparison of the two methods and the localization of the A1 segments in the B domain with increasing length of the A1 block. For Monte Carlo simulations we employ two types of chains, 2-32-30 and 1-16-15, and for the self-consistent field theory we use the corresponding values of the thermodynamic incompatibility parameter, c/v.
PL
Teorię samozgodnego pola średniego i symulacje Monte Carlo wykorzystano do oceny dystrybucji segmentów A1, B i A2 w strukturach warstwowych. Porównano wyniki uzyskane za pomocą tych dwóch metod i przedstawiono wnioski dotyczące zmian lokalizacji segmentów A1 w domenie B wraz ze zwiększaniem długości bloków A1.
6
Content available remote Monte Carlo Study of Patchy Nanostructures Self - Assembled from a Single Multiblock Chain
Krajniak J., Banaszak M.
Computational Methods in Science and Technology
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2013
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Vol. 19, No. 3
137--143
EN
We present a lattice Monte Carlo simulation for a multiblock copolymer chain of length N=240 and microarchitecture (10-10)12. The simulation was performed using the Monte Carlo method with the Metropolis algorithm. We measured average energy, heat capacity, the mean squared radius of gyration, and the histogram of cluster count distribution. Those quantities were investigated as a function of temperature and incompatibility between segments, quantified by parameter ω We determined the temperature of the coil-globule transition and constructed the phase diagram exhibiting a variety of patchy nanostructures. The presented results yield a qualitative agreement with those of the off-lattice Monte Carlo method reported earlier, with a significant exception for small incompatibilities, ω, and low temperatures, where 3-cluster patchy nanostructures are observed in contrast to the 2-cluster structures observed for the off-lattice (10 - 10)12 chain. We attribute this difference to a considerable stiffness of lattice chains in comparison to that of the off-lattice chains.
7
Content available remote Phase Diagram of Diblock Copolymer Melt in Dimension d = 5
Dzięcielski M., Lewandowski K., Banaszak M.
Computational Methods in Science and Technology
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2011
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Vol. 17, No. 1-2
17-23
EN
Using the self-consistent field theory (SCFT) in spherical unit cells of various dimensionalities, D, a phase diagram of a diblock, A-b-B, is calculated in 5 dimensional space, d = 5. This is an extension of a previuos work for d = 4. The phase diagram is parameterized by the chain composition, f, and incompatibility between A and B, quantified by the product chi N. We predict 5 stable nanophases: layers, cylinders, 3D spherical cells, 4D spherical cells, and 5D spherical cells. In the strong segregation limit, that is for large chi, the order-order transition compositions are determined by the strong segregation theory (SST) in its simplest form. While the predictions of the SST theory are close to the corresponding SCFT extrapolations for d = 4, the extrapolations for d = 5 significantly differ from them. We find that the S5 nanophase is stable in a narrow strip between the ordered S4 nanophase and the disordered phase. The calculated orderdisorder transition lines depend weakly on d, as expected.
8
Content available remote Parallel-Tempering Monte-Carlo Simulation with Feedback-Optimized Algorithm Applied to a Coil-to-Globule Transition of a Lattice Homopolymer
Lewandowski K., Knychała P., Banaszak M.
Computational Methods in Science and Technology
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2010
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Vol. 16, No. 1
29-35
EN
We present a study of the parallel tempering (replica exchange) Monte Carlo method, with special focus on the feedbackoptimized parallel tempering algorithm, used for generating an optimal set of simulation temperatures. This method is applied to a lattice simulation of a homopolymer chain undergoing a coil-to-globule transition upon cooling. We select the optimal number of replicas for different chain lengths, N = 25, 50 and 75, using replica's round-trip time in temperature space, in order to determine energy, specific heat, and squared end-to-end distance of the homopolymer chain for the selected temperatures. We also evaluate relative merits of this optimization method.
9
Content available remote Radial distribution functions and compressibility factors for binary mixture of hard spheres from molecular dynamics simulation
Kuroczycki B., Banaszak M., Jurga S.
Computational Methods in Science and Technology
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2004
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Vol. 10, nr 2
161-167
EN
Molecular dynamics simulation of binary mixtures of hard spheres with large size ratio is reported. Radial distribution functions, their contact values and the compressibility factors are recorded at three state points. A reasonably good agreement with theory and Monte Carlo simulations is shown.
10
Content available remote Low - temperature extra ordering effects in symmetric block copolymers from lattice Monte Carlo simulation
Wołoszczuk S., Banaszak M., Jurga S., Radosz M.
Computational Methods in Science and Technology
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2004
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Vol. 10, nr 2
219-228
EN
Lattice computer simulations of block copolymer melts are reported. Low-temperature lamellar ordering conjecture is presented and its justification is provided. In addition to reviewing the previous data we present a new evidence for the extra ordering effects by recording the mean squared rotational angles as a function of the reduced temperature.
11
Content available Molecular dynamics simulation of copolymers
Banaszak M.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
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2001
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Vol. 5, No 1
17-27
EN
A series of representative molecular dynamics simulations of model Lennard-Jones copolymer chains is presented. We report measurements of thermodynamic, structural and dynamic properties of our model copolymers. For neutral copolymers we confirm our version of thermodynamic perturbation theory of the first order, while for ionic copolymers we demonstrate microphase formation and the anisotropy of the counterion diffusion.
12
Content available remote Molecular dynamics simulations of ionic copolymers
Banaszak M.
Computational Methods in Science and Technology
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2000
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Vol. 6
15-24
EN
Molecular Dynamics (MD) studies of ionic diblock copolymers are reported. The symmetrical diblocks are shown to exhibit a microphase separation transition (MST) similar to that of neutral diblocks. The MST was investigated by measuring thermodynamic, structural and dynamic properties : density, simulation box dimensions, structure factor, anisotropy in structure factor and directional diffusion constants. The slow cooling of the system from a high-temperature disordered phase to low-temperature ordered microphase separated phase was achieved in both temperature controlled ('NVT') MD, and temperature and pressure controlled ('NPT') MD.
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