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

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Title:Hydrophobically Modified Amphiphilic Block Copolymer Micelles in Non-Aqueous Polar Solvents. Fluorometric, Light Scattering and Computer-Based Monte Carlo Study
Creators:
Matějíček, Pavel
Uhlík, Filip
Limpouchová, Zuzana
Procházka, Karel
Tuzar, Zdeněk
Webber, Stephen E.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 67, 5, pp. 531-556
Uncontrolled Keywords:Conformational behavior, Micellization, Block copolymers, Monte-Carlo simulations, Fluorometry, Micelles

Abstract

The micellization behavior of a hydrophobically modified polystyrene-<i>block</i>-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. <p>

Title:Hydrophobically Modified Amphiphilic Block Copolymer Micelles in Non-Aqueous Polar Solvents. Fluorometric, Light Scattering and Computer-Based Monte Carlo Study
Creators:
Matějíček, Pavel
Uhlík, Filip
Limpouchová, Zuzana
Procházka, Karel
Tuzar, Zdeněk
Webber, Stephen E.
Uncontrolled Keywords:Conformational behavior, Micellization, Block copolymers, Monte-Carlo simulations, Fluorometry, Micelles
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:67
Number:5
Page Range:pp. 531-556
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20020531UNSPECIFIED
ID Code:1940
Item Type:Article
Deposited On:06 Feb 2009 17:14
Last Modified:06 Feb 2009 16:14

Citation

Matějíček, Pavel; Uhlík, Filip; Limpouchová, Zuzana; Procházka, Karel; Tuzar, Zdeněk; Webber, Stephen E. (2002) Hydrophobically Modified Amphiphilic Block Copolymer Micelles in Non-Aqueous Polar Solvents. Fluorometric, Light Scattering and Computer-Based Monte Carlo Study. Collection of Czechoslovak Chemical Communications, 67 (5). pp. 531-556. ISSN 0010-0765

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