Zakład Fizyki Makromolekularnej
Strona główna


od 2020-09-20

Prof. UAM dr hab. Michał Banaszak  | 1999-10 <> 2008-09

Profesor UAM

  0000-0003-0106-632X     2845620     6603615390  

Publikacje           Doktorzy      Magistrowie      Licencjusze      Seminaria


Wołoszczuk S., Jurga S., Banaszak M.

Towards entropy-driven interstitial micelles at elevated temperatures from selective A1BA2 triblock solutions We simulate selective A1BA2-A and A1BA2-B triblock solutions (that is, mixtures of the A1BA2 triblock with a solvent of either type A or type B) using a lattice Monte Carlo method. Although the simulated triblock chains are compositionally symmetric in terms of the A to B volume ratio, the A1 block is significantly shorter than the A2 block. For the pure A1BA2 melt the phase behavior is relatively well known, including the existence and stability of the recently discovered interstitial micelles which were found at the very strong segregation limit. In this paper, we investigate the stability of the interstitial micelles as a function of triblock volume fraction in a selective solvent of either type A or type B. The main finding of this paper is that adding a selective solvent of type A shifts the stability of the interstitial micelles into significantly higher temperatures which may provide a pathway towards experimental studies of interstitial micelles in real triblock solutions. We also find that adding selective solvents to the A1BA2 melt gives rise to a variety of nonlamellar nanostructures for temperatures and compositions at which the interstitial micelles are stable.

Physical Review E, 94(2), 022502 (2016)

DOI: 10.1103/PhysRevE.94.022502   (Pobrane:  2020-10-23)


Wołoszczuk S., Banaszak M., Knychała P., Lewandowski K., Radosz M.

Alternating multiblock copolymers exhibiting protein-like transitions in selective solvents: A Monte Carlo study We present a lattice Monte Carlo study of a series of block copolymer chains in selective solvents of varying quality, first using a diblock chain of the length of N = 32 with a 16-16 microarchitecture, and then - two multiblock chains of N = 64 and N = 128, with (8-8)(4) and (16-16)(4) microarchitectures, respectively. We report a variety of thermodynamic and structural properties, such as energy, specific heat, end-to-end distance and radius of gyration both for the whole chain and for individual blocks. The simulations have demonstrated that a multiblock copolymer in a selective solvent exhibits protein-like behavior undergoing a two-step transition, first from a swollen state to a secondary 'pearl-necklace' state and then to a tertiary super-globular state as the solvent quality decreases, i.e. upon cooling. We have found that mean-squared end-to-end distances of multiblock chains decrease as the temperature is reduced, as expected.
(C) 2008 Elsevier B.V. All rights reserved.

Journal of Non-Crystalline Solids, 354(35-39), 4138-4142 (2008)

DOI: 10.1016/j.jnoncrysol.2008.06.022   (Pobrane:  2020-10-21)


Wołoszczuk S., Banaszak M., Knychała P., Radosz M.

Monte Carlo phase diagram of symmetric diblock copolymer in selective solvent With a lattice Monte Carlo method, we investigate 16-16 symmetric diblock in selective solvent, A-b-B/A, at 10 volume fractions from 1.0 to 0.1, and for each volume fraction, we perform simulations at up to 54 temperatures, using simulation boxes of different sizes. We report temperature dependencies for a number of quantities such as energy, specific heat, and mean-squared end-to-end distances and construct a phase diagram using the thermodynamic and structural quantities as well as snapshots of the selected configurations. The simulated phase diagram is compared with the experimental data of Lodge and co-workers for nearly symmetric poly(styrene-b-isoprene) mixed with dimethyl phthalate.

Macromolecules, 41(15), 5945-5951 (2008)

DOI: 10.1021/ma0718346   (Pobrane:  2020-10-23)


Śliwińska-Bartkowiak M., Ratajczak B., Golibrocki L., Banaszak M.

An apparent critical point in binary mixtures: Experimental and simulation study We report the experimental and simulation studies for the system of nitrobenzene-cyclododecane, showing an apparent critical point, which lies in their metastable, experimentally inaccessible state, below their melting point, affecting physical and chemical properties of this system in the stable liquid phase. The nonlinear dielectric effect (NDE) was measured in the mixture of nitrobenzene with cyclododecane. The mixture has been found to show an apparent critical point which lies below the melting point, manifested as anomalous NDE behavior in the vicinity of the critical concentrations in the stable liquid phase. The melting temperature of this system was estimated using the differential scanning calorimetry method. For such a system, we also performed Monte Carlo (MC) simulations that aimed to analyze the kinds of phase transitions observed and the conditions of their occurrence in Lennard-Jones mixture. The enthalpy, configurational energy, and radial distribution function have been estimated by the MC simulation method in the N-P-T system. Immiscibility conditions according to the approach by Schoen and Hoheisel [Mol. Phys. 57, 65 (1986)] are also discussed.

Journal of Chemical Physics, 124(14), 144516 (2006)

DOI: 10.1063/1.2191052   (Pobrane:  2020-10-23)


Wołoszczuk S., Banaszak M., Jurga S., Pakuła T., Radosz M.

Low-temperature ordering effects in diblock copolymer melts from lattice simulation A lattice simulation of a model diblock copolymer melt is presented. In a series of simulation experiments an 8-8 diblock melt is quenched from an athermal state to 47 lower temperatures. A set of simulation boxes, 30x32x30, 40x32x60, 50x32x30, and 60x32x30, is used in order to explore the size effects. Energy, specific heat, copolymer end-to-end distance, lamellar spacing, and the degree of interfacial ordering are reported. For all sizes considered, the low-temperature interfacial ordering is noticeable.
(C) 2004 American Institute of Physics.

Journal of Chemical Physics, 121(23), 12044-12049 (2004)

DOI: 10.1063/1.1812751   (Pobrane:  2020-10-21)


Kuroczycki B., Banaszak M., Jurga S.

Radial distribution fuctions and compressibility factors for binary mixture of hard spheres from molecular dynamics simulation 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.

Computational Methods in Science and Technology, 10(2), 161-167 (2004)

DOI: 10.12921_cmst.2004.10.02.161-167
WWW:   (Pobrane:  2020-10-23)


Wołoszczuk S., Banaszak M., Jurga S., Radosz M.

Low-temperature extra ordering effects in symmetric block copolymers from lattice monte carlo simulation 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.

Computational Methods in Science and Technology, 10(2), 219-228 (2004)

DOI: 10.1292/cmst.2004.10.02.219-228


Banaszak M., Wołoszczuk S., Jurga S., Pakuła T.

Lamellar ordering in computer-simulated block-copolymer melts by a variety of thermal treatments A lattice computer simulation of a symmetric A-B-A triblock copolymer melt is reported. This melt is quenched, in simulation, from an athermal state to 39 different temperatures using cooperative motion algorithm. Energy, specific heat, copolymer end-to-end distance, bridging fraction, lamellar spacing, concentration profiles, and microstructure visualizations are reported. The quenching simulation results are compared with those obtained by alternative thermal treatments, that is by slow heating and slow cooling. Quenches yield data consistent with theory and experiment, whereas slow cooling and slow heating results do not capture the expected behavior for the lamellar spacing and the bridging fraction. Finally, at very low temperatures, below the conventional order-disorder transition temperature, an additional ordering is recorded, from a conventional lamellar phase to a lamellar structure showing copolymer junction points condensed into a two-dimensional plane.
(C) 2003 American Institute of Physics.

Journal of Chemical Physics, 119(21), 11451-11457 (2003)

DOI: 10.1063/1.1622375   (Pobrane:  2020-10-21)


Banaszak M., Wołoszczuk S., Pakuła T., Jurga S.

Computer simulation of structure and microphase separation in model A-B-A triblock copolymers A set of computer simulations for three symmetric A-B-A triblock copolymer microarchitectures at varying temperatures is reported. By using the cooperative motion algorithm we obtain energy, specific heat, end-to-end distance, and bridging fraction as a function of the reduced temperature. The order-disorder transition temperatures are determined, an outline of a symmetric A-B-A triblock copolymer phase diagram is presented, and the visualization of different microstructures is given. A bicontinuous microstructure is reported at 67% fraction of A component.

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 66(3), 031804 (2002)

DOI: 10.1103/PhysRevE.66.031804


Banaszak M., Radosz M.

Molecular dynamics study on homonuclear and heteronuclear chains of Lennard-Jones segments We report molecular dynamics (MD) simulation data for three simulated fluids: a homopolymer with 16 tangent Lennard-Jones (U) segments at the reduced temperature of 1.25, an equimolar binary homopolymer fluid with eight tangent U segments at 15 state points, and three corresponding copolymers with equimolar segment fraction and varying segment distribution at 15 state points. We find that the compressibility factors and energies do not change as the segment distribution varies in the copolymer example. The simulation data are compared with thermodynamic perturbation theory (TPT1) calculations, The TPT1 compressibility factors compare favorably with the MD data at high reduced temperatures but differ significantly at lower temperatures.
(C) 2002 Elsevier Science B.V. All rights reserved.

Fluid Phase Equilibria, 193(1-2), 179-189 (2002)

DOI: 10.1016/S0378-3812(01)00730-0   (Pobrane:  2020-10-21)


Banaszak M.

Molecular dynamics simulation of copolymers 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.

Task Quartely, 5(1), 17-27 (2001)

ISSN: 1428-6394   (Pobrane:  2021-01-07)


Banaszak M.

Molecular dynamics simulations of ionic copolymers 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.

Computational Methods in Science and Technology, 6, 15-24 (2000)

DOI: 10.12921_cmst.2000.06.01.15-24


Banaszak M., Clarke J.H.R.

Computer simulation of microphase separation in ionic copolymers The formation of lamella microphases in symmetric neutral-ionic block copolymers has been investigated by constant volume-constant temperature (NVT) molecular-dynamics computer simulations using a generic coarse-grain model. Computations of counterion diffusion, pressure tensor, and the anisotropy of the structure factor are used to characterize the order-disorder transition (ODT). There is strong counterion condensation on the ionic blocks at temperatures well above the ODT; this creates a slight imbalance in the volume composition of the two blocks and results in a perforated lamella structure in the microphase. Below the ODT counterion diffusion is decoupled from the chain motions but is strongly anisotropic due to the microphase morphology. The high counterion diffusional mobility is discussed in terms of the relatively low value of the glass transition for the ionic blocks. [S1063-651X(99)05711-6].

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 60(5), 5753-5756 (1999)

DOI: 10.1103/PhysRevE.60.5753


Chen C.K., Banaszak M., Radosz M.

Statistical associating fluid theory equation of state with Lennard-Jones reference applied to pure and binary n-alkane systems A prototype equation of state, developed on the basis of thermodynamic perturbation theory of the first order (TPT1), using the Lennard-Jones potential for the reference fluid, is found to represent pure-fluid and binary phase equilibria in the systems of small chain molecules, such as normal alkanes.

Journal of Physical Chemistry B, 102(13), 2427-2431 (1998)

DOI: 10.1021/jp9731819


Banaszak M., Chen C.K., Radosz M.

Copolymer SAFT equation of state. Thermodynamic perturbation theory extended to heterobonded chains Thermodynamic perturbation theory of the first order (TPT1) is extended to heterobonded chains, such as heteronuclear and branched copolymers. The TPT1 formalism provides the basis for a copolymer equation of state. This new copolymer equation of state, referred to as Copolymer SAFT (Statistical Associating Fluid Theory), explicitly accounts for the effects of chain heterogeneity and microstructure. In order to illustrate potential future applications, Copolymer SAFT is used to calculate high-pressure cloud points in real polymer solutions of supercritical propane + poly(ethylene-co-butene).

Macromolecules, 29(20), 6481-6486 (1996)

DOI: 10.1021/ma9517815


Banaszak M., Chiew Y.C., Radosz M.

Mixing rules for binary Lennard-Jones fluid structures The mixing rule estimates of the radial distribution functions g(alpha beta)(r), from the van der Waals one-fluid and mean density approximations for Lennard-Jones fluid mixtures, are examined by comparing with Monte Carlo simulations. In addition, these mixing rule estimates of g(alpha beta)(r) are used to calculate the Helmholtz energy for Lennard-Jones homonuclear chain mixtures based on the thermodynamic perturbation theory (TPT). Two simplifying modifications of these mixing rules are proposed for the TPT mixture model. The accuracy of these simplified rules is examined and found to give accurate representation of the theoretically derived Helmholtz energy over a wide range of densities and temperatures.

Fluid Phase Equilibria, 111(2), 161-174 (1995)

DOI: 10.1016/0378-3812(95)02736-X   (Pobrane:  2020-10-23)


Chen S.J., Banaszak M., Radosz M.

Phase behavior of poly(ethylene-1-butene) in subcritical and supercritical propane - ethyl branches reduce segment energy and enhance miscibility On the basis of experimental batch-cell data, increasing short-chain branch density is found to reduce the cloud-point pressure of poly(ethylene-1-butene) solutions in propane, by as much as a factor of 3. This trend is captured by a SAFT approximation via an effective segment energy that depends on the branch density. Increasing branch density is found to decrease the effective segment energy and, hence, to make it closer to that of propane, which is consistent with the enhanced miscibility of branchy poly(ethylene-1-butenes) in propane.

Macromolecules, 28(6), 1812-1817 (1995)

DOI: 10.1021/ma00110a014


Banaszak M., Chiew Y.C., Olenick R., Radosz M.

Thermodynamic perturbation theory - Lennard-Jones chains The compressibility factors for freely-jointed Lennard-Jones chains are determined in the context of Wertheim's first-order thermodynamic perturbation theory (TPT1). In the TPT1 treatment, nonbonded Lennard-Jones spheres are used as the reference system. The compressibility factors of the chain system, at temperature T*, segment density ρ*, and chain length m, are obtained based on the compressibility factors of the Lennard-Jones spheres, and the density derivative of the radial distribution function, partial derivative ln g(LIS)(σρ*,T*)/partial derivative ρ*, evaluated at the same temperature T* and segment density ρ*. The exact values for these two quantities, obtained from Monte Carlo simulations, are used in our calculations. The TPT1 predictions are found in agreement with Monte Carlo simulation results for the 8-mer, 16-mer, and 32-mer Lennard-Jones chains over a wide range of densities and temperatures. When values of the density derivative of the reference Lennard-Jones sphere system are estimated from the approximate Weeks-Chandler-Andersen perturbation theory, however, the TPT1 predictions do not match the simulation results.

Journal of Chemical Physics, 100(5), 3803-3807 (1994)

DOI: 10.1063/1.466368   (Pobrane:  2020-10-23)


Banaszak M., Petsche I.B., Radosz M.

Repeat-unit interaction energies for lattice cluster theory derived from sans data for blends of random poly(ethylene-butene-1) The SANS data for binary random poly(ethylene-butene-1) blends are analyzed using the lattice cluster theory (LCT) which relates bulk polymer properties to repeat-unit structures. The random poly(ethylene-butene-1)chains are approximated as monodisperse homopolymers. LCT repeat-unit interaction energies epsilon, epsilon11, and epsilon22 are fitted to the Flory chi parameters obtained from the SANS experiments. The calculated chi parameters have the correct temperature dependence, and the predicted UCST's agree with the experimental data.

Macromolecules, 26(2), 391-395 (1993)

DOI: 10.1021/ma00054a020


Banaszak M., Chiew Y.C., Radosz M.

Thermodynamic perturbation-theory - sticky chains and square-well chains We extend Wertheim's first-order thermodynamic perturbation theory [J. Chem. Phys. 87, 7323 (1987)] to sticky chains and square-well chains. The predicted compressibility factors for square-well chains are found to agree with Monte Carlo data. We demonstrate that the effect of chain connectivity is to reduce the attraction contributions to the compressibility factor and to the critical temperatures.

Physical Review E - Statistical, Nonlinear and Soft Matter Physics, 48(5), 3760-3765 (1993)

DOI: 10.1103/PhysRevE.48.3760   (Pobrane:  2020-10-23)


Banaszak M., Whitmore M.D.

Mean field-theory of the phase-behavior of ternary block copolymer-homopolymer blends We have extended and applied the theory of polymer blends developed by Hong and Noolandi to the calculation of phase diagrams of ternary A-b-B/A/B copolymer/homopolymer blends which can undergo microphase and macrophase separation. The approach used a perturbative solution to the modified diffusion equation to calculate the polymer distribution functions and the free energy. For simplicity, we assumed that the microphase is lamellar and calculated the free energy up to fourth order. The main results are phase diagrams for a variety of model systems containing symmetric or asymmetric copolymers mixed with homopolymers of varying molecular weights and for a PS-b-PI/PS/PI mixture. We also compared induced microphase formation in ternary and binary blends. It is particularly interesting in blends containing asymmetric copolymers and/or A and B homopolymers having differing molecular weights.

Macromolecules, 25(1), 249-260 (1992)

DOI: 10.1021/ma00027a042


Banaszak M., Whitmore M.D.

Mean field-theory of the lamellar structure of block copolymer homopolymer blends in the weak segregation regime We have studied the lamellar structure of binary A-b-B/A and ternary A-b-B/A/B copolymer/homopolymer blends near the microphase separation transition. The approach combines perturbative solutions to the modified diffusion equation with a model for the total A and B polymer density profiles. We calculated, approximately, the equilibrium domain and subdomain thicknesses, swelling of the copolymers by the homopolymers, individual polymer density profiles, and their dependence on the copolymer and homopolymer degrees of polymerization, composition, and Flory interaction parameter. The results were compared with numerical solutions to the full self-consistent theory for related copolymer/solvent blends and to three sets of experiments on copolymer/homopolymer blends. The calculations were consistent with the picture that added homopolymers tend to penetrate within the copolymers and swell them laterally and that the degree to which this occurs depends on the relative molecular weights of the copolymers and homopolymers. The tendency of added homopolymers to cause an increase or decrease in the domain thickness correlates with their tendency to stabilize or destabilize the microphase.

Macromolecules, 25(10), 2757-2770 (1992)

DOI: 10.1021/ma00036a030


Banaszak M., Whitmore M.D.

Self-consistent theory of block copolymer blends - selective solvent We present a theoretical study of the lamellar microphase of block copolymer/selective solvent blends in which the solvent is good for one block and either good or near-theta for the other. The calculations used numerical solutions to the equations of the self-consistent mean-field theory of polymer blends. Two types of systems were studied. In the first, all pure-component densities were taken to be equal, as were the two Kuhn statistical lengths, and the solvent was idealized as being a thermal for one of the blocks. In the other type, realistic values for these parameters were used; calculations were carried out for the particular case of PS-b-PBD/styrene. We examined the dependence of the lamellar thickness on molecular weight, overall concentration, and Flory interaction parameters, and we discuss the solvent and polymer density profiles. We compare the predictions for blends with selective solvents with previous ones for nonselective solvent cases, and we compare the idealized systems with real systems. The theory predicts some significant differences between the idealized and real systems.

Macromolecules, 25(13), 3406-3412 (1992)

DOI: 10.1021/ma00039a015   (Pobrane:  2020-10-23)

 © Opisy i zdjęcia: Zakład Fizyki Makromolekularnej  | Ta stona używa ciasteczek
     Zaktualizowano: podstrony  2021-06-21  / bazę danych:   2021-08-30  by Webmaster: Zbigniew Fojud