A Monte Carlo study of shells of hydrophobically modified amphiphilic copolymer micelles in polar solvents

2003 ◽  
Vol 118 (24) ◽  
pp. 11258-11264 ◽  
Author(s):  
Filip Uhlı́k ◽  
Zuzana Limpouchová ◽  
Karel Jelı́nek ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
Amphiphilic Copolymer ◽  
Polar Solvents ◽  
Hydrophobically Modified ◽  
Copolymer Micelles

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.

Homopolymer Solubilization Limits in Copolymer Micelles:  A Monte Carlo Study

2000 ◽  
Vol 33 (23) ◽  
pp. 8654-8662 ◽  
Author(s):  
M. P. Pépin ◽  
M. D. Whitmore
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
Copolymer Micelles

A Monte Carlo Study of Insoluble Block Orientations in Swollen Cores of Multimolecular Block Copolymer Micelles

1994 ◽  
Vol 59 (4) ◽  
pp. 803-819 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Distribution Functions ◽  
Excluded Volume Effect ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
End To End ◽  
Tethered Chains ◽  
Self Avoiding Walk

Conformations of tethered chains in restricted spherical volumes with an increasing radius were studied by Monte Carlo simulations. Simulations were performed on a tetrahedral lattice at relatively high densities of the occupied lattice sites. A simultaneous self-avoiding walk of all tethered chains creates the starting conformations of the multi-chain system which are futher equilibrated by a modified algorithm similar to that of Siepmann and Frenkel. In this paper, only a geometric excluded volume effect of segments is considered. Selectively chosen series of data for changing numbers of chains, N, their lengths, L, and radii of the sphere, R, give information on the system behavior under various conditions. In this part of our systematic study of tethered chains in constrained volumes, we present angular distribution functions of the end-to-end, end-to-gravity center distances, etc. for system studied in previous paper. The second class of studied conformational characteristics are the distributions of projections of the end-to-end vectors into the selected directions (i.e. the radial direction and the direction of the first-to-second polymer segment connection).

Hydrophobically Modified Amphiphilic Block Copolymer Micelles in Non-Aqueous Polar Solvents. Fluorometric, Light Scattering and Computer-Based Monte Carlo Study

2002 ◽  
Vol 67 (5) ◽  
pp. 531-556 ◽  
Author(s):  
Pavel Matějíček ◽  
Filip Uhlík ◽  
Zuzana Limpouchová ◽  
Karel Procházka ◽  
Zdeněk Tuzar ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Light Scattering ◽  
Aqueous Media ◽  
Excitation Energy Transfer ◽  
Monte Carlo Study ◽  
Fluorescence Decay ◽  
Model Systems ◽  
Interfacial Region ◽  
Hydrophobically Modified ◽  
Rich Mixtures

The micellization behavior of a hydrophobically modified polystyrene-block-poly(methacrylic acid) diblock copolymer, PS-N-PMA-A, tagged with naphthalene between blocks and with anthracene at the end of the PMA block, was studied in 1,4-dioxane-methanol mixtures by light scattering and fluorescence techniques. The behavior of a single-tagged sample, PS-N-PMA, and low-molar-mass analogues was studied for comparison. Methanol-rich mixtures with 1,4-dioxane are strong selective precipitants for PS. Multimolecular micelles with compact PS cores and PMA shells may be prepared indirectly by dialysis from 1,4-dioxane-rich mixtures, or by a slow titration of copolymer solutions in 1,4-dioxane-rich solvents with methanol under vigorous stirring. In tagged micelles, the naphthalene tag is trapped in nonpolar and fairly viscous core/shell interfacial region. In hydrophobically modified PS-N-PMA-A micelles, the hydrophobic anthracene at the ends of PMA blocks tends to avoid the bulk polar solvent and buries in the shell. The distribution of anthracene tags in the shell is a result of the enthalpy-to-entropy interplay. The measurements of direct nonradiative excitation energy transfer were performed to estimate the distribution of anthracene-tagged PMA ends in the shell. The experimental fluorometric data show that anthracene tags penetrate into the inner shell in methanol-rich solvents. Monte Carlo simulations were performed on model systems to get reference data for analysis of time-resolved fluorescence decay curves. A comparison of experimental and simulated decays indicates that hydrophobic traps return significantly deep into the shell (although not as deep as in aqueous media). The combined light scattering, fluorometric and computer simulation study shows that the conformational behavior of shell-forming PMA blocks in non-aqueous media is less affected by the presence of nonpolar traps than that in aqueous media.

Polyelectrolyte shells of copolymer micelles in aqueous solutions: A Monte Carlo study

2004 ◽  
Vol 121 (5) ◽  
pp. 2367-2375 ◽  
Author(s):  
Filip Uhlı́k ◽  
Zuzana Limpouchová ◽  
Karel Jelı́nek ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Aqueous Solutions ◽  
Monte Carlo Study ◽  
Copolymer Micelles
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