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 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.

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 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).

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

Analyzing Observed Composite Differences Across Groups

Methodology ◽  
2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Holger Steinmetz
Keyword(s):  
Monte Carlo ◽  
Structural Equation Modeling ◽  
Measurement Invariance ◽  
Structural Equation ◽  
Monte Carlo Study ◽  
Equation Modeling ◽  
Factor Loadings ◽  
Latent Mean Differences ◽  
Partial Invariance ◽  
Mean Differences

Although the use of structural equation modeling has increased during the last decades, the typical procedure to investigate mean differences across groups is still to create an observed composite score from several indicators and to compare the composite’s mean across the groups. Whereas the structural equation modeling literature has emphasized that a comparison of latent means presupposes equal factor loadings and indicator intercepts for most of the indicators (i.e., partial invariance), it is still unknown if partial invariance is sufficient when relying on observed composites. This Monte-Carlo study investigated whether one or two unequal factor loadings and indicator intercepts in a composite can lead to wrong conclusions regarding latent mean differences. Results show that unequal indicator intercepts substantially affect the composite mean difference and the probability of a significant composite difference. In contrast, unequal factor loadings demonstrate only small effects. It is concluded that analyses of composite differences are only warranted in conditions of full measurement invariance, and the author recommends the analyses of latent mean differences with structural equation modeling instead.

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