A Monte Carlo Study of Copolymer Chain Conformations in Dilute Solutions in Good and Selective Solvents

1995 ◽  
Vol 60 (5) ◽  
pp. 736-750
Author(s):  
Tereza Vrbová ◽  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Diblock Copolymers ◽  
Structural Characteristics ◽  
Monte Carlo Study ◽  
Dilute Solutions ◽  
Copolymer Chain ◽  
Selective Solvents ◽  
Nearest Neighbours ◽  
Lattice Distance ◽  
Chain Conformations

Conformations of symmetric diblock copolymers AB in dilute solutions in good and selective solvents were studied by Monte Carlo simulations on a simple cubic lattice. Individual chain conformations were created by the self-avoiding walk algorithm. A modified thermal equilibration of the system based on the Metropolis acceptance criteria for energies of the system and the Rosenbluth weights of chain conformations was applied. Interactions of the nearest neighbours (r = l), where l is the lattice distance, and interactions for r = sqrt(2l) and r = sqrt(3l) were considered. Various structural characteristics of the whole copolymer chain and individual blocks A, B were obtained in the course of computer simulations. It was found that a moderate contraction of the worse soluble block B and a certain segregation of blocks occurs in dilute solutions in selective solvents for the block A, however neither that contraction, nor the segregation of blocks are extensive.

Monte Carlo Study of Symmetric Diblock Copolymers in Selective Solvents

1995 ◽  
Vol 28 (8) ◽  
pp. 2705-2713 ◽  
Author(s):  
Luis A. Molina ◽  
Juan J. Freire
Keyword(s):  
Monte Carlo ◽  
Diblock Copolymers ◽  
Monte Carlo Study ◽  
Selective Solvents

scholarly journals Diagrams of States of Single Flexible-Semiflexible Multi-Block Copolymer Chains: A Flat-Histogram Monte Carlo Study

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 757 ◽  
Author(s):  
Daria Maltseva ◽  
Sergey Zablotskiy ◽  
Julia Martemyanova ◽  
Viktor Ivanov ◽  
Timur Shakirov ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Total Energy ◽  
Single Molecule ◽  
Materials Science ◽  
Monte Carlo Study ◽  
Monte Carlo Algorithm ◽  
Implicit Solvent ◽  
Multiblock Copolymer ◽  
Copolymer Chain ◽  
Selective Solvents

The combination of flexibility and semiflexibility in a single molecule is a powerful design principle both in nature and in materials science. We present results on the conformational behavior of a single multiblock-copolymer chain, consisting of equal amounts of Flexible (F) and Semiflexible (S) blocks with different affinity to an implicit solvent. We consider a manifold of macrostates defined by two terms in the total energy: intermonomer interaction energy and stiffness energy. To obtain diagrams of states (pseudo-phase diagrams), we performed flat-histogram Monte Carlo simulations using the Stochastic Approximation Monte Carlo algorithm (SAMC). We have accumulated two-Dimensional Density of States (2D DoS) functions (defined on the 2D manifold of macrostates) for a SF-multiblock-copolymer chain of length N = 64 with block lengths b = 4, 8, 16, and 32 in two different selective solvents. In an analysis of the canonical ensemble, we calculated the heat capacity and determined its maxima and the most probable morphologies in different regions of the state diagrams. These are rich in various, non-trivial morphologies, which are formed without any specific interactions, and depend on the block length and the type of solvent selectivity (preferring S or F blocks, respectively). We compared the diagrams with those for the non-selective solvent and reveal essential changes in some cases. Additionally, we implemented microcanonical analysis in the “conformational” microcanonical ( N V U , where U is the potential energy) and the true microcanonical ( N V E , where E is the total energy) ensembles with the aim to reveal and classify pseudo-phase transitions, occurring under the change of temperature.

A Monte Carlo Study of Flexible Polymer Chain Conformations in Restricted Volumes. I. A Model for Insoluble Blocks Conformations in Swollen Cores of Multimolecular Spherical Block Copolymer Micelles

1993 ◽  
Vol 58 (10) ◽  
pp. 2290-2304 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Block Copolymer ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Micellar Systems ◽  
Flexible Polymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Chain Conformations ◽  
Chain Lengths

Monte Carlo simulations of chain conformations in a restricted spherical volume at relatively high densities of segments were performed for various numbers of chains, N, and chain lengths (number of segments), L, on a tetrahedral lattice. All chains are randomly end-tethered to the surface of the sphere. A relatively uniform surface density of the tethered ends is guaranteed in our simulations. A simultaneous self-avoiding walk of all chains creates starting conformations for a subsequent equilibration. A modified algorithm similar to that of Siepmann and Frenkel is used for the equilibration of the chain conformations. In this paper, only a geometrical excluded volume effect of segments is considered. Various structural and conformational characteristics, e.g. segment densities gS(r), free end densities gF(r) as functions of the position in the sphere (a distance from the center), distributions of the tethered-to-free end distances, ρTF(rTF), etc. are calculated and their physical meaning is discussed. The model is suitable for studies of chain conformations is swollen cores of multimolecular block copolymer micelles and for interpretation of non-radiative excitation energy migration in polymeric micellar systems.

Monte Carlo study of the micelles constructed by ABCA tetrablock copolymers and their formation in A-selective solvents

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86473-86484 ◽  
Author(s):  
Jiani Ma ◽  
Jie Cui ◽  
Yuanyuan Han ◽  
Wei Jiang ◽  
Yingchun Sun
Keyword(s):  
Monte Carlo ◽  
Outer Surface ◽  
Monte Carlo Study ◽  
Selective Solvent ◽  
Selective Solvents

Micelles with hamburger-type and Janus-type solvophobic parts, asymmetric vesicles with multicompartment outer surface formed by ABCA tetrablock copolymers in A-selective solvent.

Charged Star Diblock Copolymers in Dilute Solutions: Synthesis, Structure, and Chain Conformations

2015 ◽  
Vol 48 (8) ◽  
pp. 2637-2646 ◽  
Author(s):  
Sara Bekhradnia ◽  
Jakob Stensgaard Diget ◽  
Thomas Zinn ◽  
Kaizheng Zhu ◽  
Sverre Arne Sande ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Dilute Solutions ◽  
Chain Conformations ◽  
Charged Star

Conformations of Insoluble Blocks in Swollen Micellar Cores of Multimolecular Block Copolymer Micelles Studied by Monte Carlo Simulation Technique

1994 ◽  
Vol 59 (4) ◽  
pp. 782-802 ◽  
Author(s):  
Karel Procházka ◽  
Zuzana Limpouchová
Keyword(s):  
Monte Carlo ◽  
Chain Flexibility ◽  
Monte Carlo Simulation Technique ◽  
Geometrical Constraints ◽  
Lattice Distance ◽  
Block Copolymer Micelles ◽  
Chain Conformations ◽  
Chain Lengths ◽  
Self Avoiding Walk ◽  
Physical Quantities

Monte Carlo simulations of chain conformations in restricted spherical volumes with an increasing radius were performed on a tetrahedral lattice (ca 2 700 to 9 200 lattice sites) at relatively high densities of the occupied lattice sites. A simultaneous self-avoiding walk together with the equilibration algorithm similar to that of Siepmann and Frenkel were used to create the equilibrated multi-chain conformations. (a) A series of simulations was carried out for a constant average segment density, <gS> = 0.52, together with the three values of the radius of the sphere, R = 10 l, 12.5 l and 15 l (l is the lattice distance), and various numbers of chains, N ∈ <15, 86>, and chain lengths, L ∈ <31, 163>. The results give information on the system behavior and on the effects of: (i) multi-chain conformational correlations, which depend both on N and L, (ii) the L-dependent chain flexibility, and (iii) R-dependent external geometrical constraints. Another two series of data: (b) for a constant average segment density, <gS> = 0.36, a constant N = 21, and L proportional to R3, and (c) for <gS> = 0.36, L = 47 and N proportional to R3, are shown to give a supplementary detailed information on conformational behavior of individual chains. Various physical quantities (e.g. the densities of chain free ends, gF(r), or distributions of the tethered end-to-the free end distances, ρTF(rTF), etc.) were calculated in the course of computer simulations and their shapes and physical significance is discussed with respect to the changing values of N, L and R.

Monte Carlo Study of Dilute Solutions of Heteroarm Star Copolymers in Solvents Differing in Thermodynamic Quality

2005 ◽  
Vol 70 (11) ◽  
pp. 1848-1860 ◽  
Author(s):  
Jitka Havránková ◽  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Common Good ◽  
Molecular Level ◽  
Monte Carlo Study ◽  
Coarse Graining ◽  
Quantitative Agreement ◽  
Conformational Behavior ◽  
Lattice Monte Carlo ◽  
Selective Solvents ◽  
Star Copolymers

Lattice Monte Carlo simulations (an original modification of the Siepmann and Frenkel simulation variant) was used to study the conformational behavior of heteroarm star copolymers star-(polystyrene; polyisoprene), PS8PI8, in a common good solvent for both types of arms (tetrahydrofuran) and in selective θ-solvents for both types of arms (in cyclohexane, i.e., in θ-solvent for PS and in 1,4-dioxane, i.e. in θ-solvent for PI). Results of simulations were compared with experimental data published by Pispas et al. The coarse graining procedure was performed to match the experimental behavior of heteroarm stars in a good solvent. The computer simulations reproduce all decisive trends of the conformational behavior for both selective solvents. The quantitative agreement between experimental and simulated size characteristics is very good. Simulations yield very detailed information on the system at the molecular level and show that the incompatible arms significantly segregate in selective solvents.

Self-association of copolymers with various composition profiles

2010 ◽  
Vol 75 (4) ◽  
pp. 493-505 ◽  
Author(s):  
Jitka Kuldová ◽  
Peter Košovan ◽  
Zuzana Limpouchová ◽  
Karel Procházka ◽  
Oleg V. Borisov
Keyword(s):  
Self Assembly ◽  
Diblock Copolymers ◽  
Monte Carlo Study ◽  
Pair Interaction ◽  
Selective Solvents ◽  
Structure Of Associates ◽  
Association Behavior ◽  
Composition Profiles ◽  
Self Association

In this paper, we present Monte Carlo study of the self-assembly of linear copolymers consisting of two types of segments (well soluble A and insoluble B segments) in selective solvents. We used simple lattice model: chains were represented by self-avoiding random walks and quality of solvent for both types of segments was controlled by pair interaction parameters. We analyzed how the association behavior depends on the composition profile, i.e., on the sequence of segments A and B along the chain. The size and structure of associates formed by chains with different composition profiles were compared with those of diblock copolymers with the same content of A and B segments. It was shown that even small changes in the sequence of segments within the chains lead to significant differences in the association behavior. In addition to composition profiles, we also shown how the association behavior depends on the quality of solvent and copolymer concentration.

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