Study of Sedimentation Velocity of Block Copolymer Micelles

1993 ◽  
Vol 58 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Minmin Tian ◽  
C. Ramireddy ◽  
Stephen E. Webber ◽  
Petr Munk
Keyword(s):  
Block Copolymer ◽  
Methacrylic Acid ◽  
Mixed Solvent ◽  
Hard Spheres ◽  
Sedimentation Velocity ◽  
Hydrodynamic Coefficient ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Size Heterogeneity ◽  
Good Agreement

No anomalies were observed during the measurement of sedimentation coefficients of block copolymer micelles formed by copolymers of styrene and methacrylic acid in a mixed solvent; 80 vol.% of dioxane and 20 vol.% of water. The shapes of the sedimenting boundaries suggest that the size heterogeneity of the micelles is small. Linear relations between 1/s and c were obtained. The value of the hydrodynamic coefficient κ was between 2 and 4 in a good agreement with the value 2.75 or 2.86 that was obtained by combining Burgers' or Fixman's values of the coefficient of the concentration dependence kvs for hard spheres with Einstein's value of [η] for spheres.

Fluorometric and Ultraviolet−Visible Absorption Study of Poly(methacrylic acid) Shells of High-Molar-Mass Block Copolymer Micelles†

Langmuir ◽  
1999 ◽  
Vol 15 (12) ◽  
pp. 4185-4193 ◽  
Author(s):  
Miroslav Štěpánek ◽  
Klára Podhájecká ◽  
Karel Procházka ◽  
Yue Teng ◽  
Stephen E. Webber
Keyword(s):  
Block Copolymer ◽  
Methacrylic Acid ◽  
Molar Mass ◽  
Absorption Study ◽  
Visible Absorption ◽  
High Molar Mass ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Study of Sedimentation Velocity of Block Copolymer Micelles

1993 ◽  
Author(s):  
Minmin Tian ◽  
C. Ramireddy ◽  
Stephen E. Webber ◽  
Petr Munk
Keyword(s):  
Block Copolymer ◽  
Sedimentation Velocity ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Styrene/butadiene block copolymer micelles in heptane

1985 ◽  
Vol 63 (1) ◽  
pp. 249-252 ◽  
Author(s):  
T. L. Bluhm ◽  
M. D. Whitmore
Keyword(s):  
Block Copolymer ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Micelle Core ◽  
Theoretical Predictions ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Styrene Butadiene ◽  
Good Agreement

The radius of gyration of poly(styrene-b-butadiene) block copolymer micelles in n-heptane is measured by small angle X-ray scattering (SAXS). The results are compared with theoretical predictions, and good agreement is found, particularly for the appropriate scaling relations. It is argued that the radius of gyration of the micelles depends on both the molecular weight and the composition of the copolymers. The dominant factors which determine the micelle core and corona dimensions are identified.

Block Copolymer Micelles in Aqueous Media

1993 ◽  
Vol 58 (10) ◽  
pp. 2362-2369 ◽  
Author(s):  
Zdeněk Tuzar ◽  
Pavel Kratochvíl ◽  
Karel Procházka ◽  
Petr Munk
Keyword(s):  
Methacrylic Acid ◽  
Dynamic Equilibrium ◽  
Aqueous Media ◽  
Sedimentation Velocity ◽  
Micellar System ◽  
Micellar Systems ◽  
Large Particles ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Rich Mixtures

Micellization of di- and triblock copolymers, poly(methacrylic acid)-block-polystyrene and poly(methacrylic acid)-block-polystyrene-block-poly(methacrylic acid), varying in molecular weight and composition, has been studied by static and dynamic light scattering, and sedimentation velocity. Micelles with polystyrene cores were prepared in water-dioxane mixtures, rich in dioxane, and transferred into water-rich mixtures, water, and aqueous buffers via stepwise dialysis. It has been shown that, in dioxane-rich mixtures, the micellar system was in dynamic equilibrium, while in water-rich solvents, water, and aqueous buffers the micellization equilibrium was frozen and micelles behaved like autonomus particles. Under certain conditions, micelles were accompanied by independent large particles. This phenomenon, known from other micellar systems as an "anomalous micellization", is discussed.

Polystyrene-poly(methacrylic acid) block copolymer micelles

1994 ◽  
Vol 27 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Anwei Qin ◽  
Minmin Tian ◽  
C. Ramireddy ◽  
Stephen E. Webber ◽  
Petr Munk ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Methacrylic Acid ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

β-lactam Functionalized Poly(isoprene-b-ethylene oxide) Amphiphilic Block Copolymer Micelles as a New Nanocarrier System for Curcumin

2010 ◽  
Vol 6 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Konstantinos Gardikis ◽  
Konstantinos Dimas ◽  
Aristidis Georgopoulos ◽  
Eleni Kaditi ◽  
Stergios Pispas ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Ethylene Oxide ◽  
Amphiphilic Block Copolymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Donnan Equilibria in Polymeric Micellar Systems with Weak Polyelectrolyte Shells: The Lowering of the pH Value

1997 ◽  
Vol 62 (11) ◽  
pp. 1730-1736 ◽  
Author(s):  
Petr Munk ◽  
Zdeněk Tuzar ◽  
Karel Procházka
Keyword(s):  
Ionic Strength ◽  
Block Copolymer ◽  
Ph Value ◽  
Electrolyte Solutions ◽  
Hydrogen Ions ◽  
Micellar Systems ◽  
Weak Electrolytes ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Polyelectrolyte Solutions

When two electrolyte solutions are separated and only some of the ions can cross the boundary, the concentrations of these ions are different on both sides of the boundary. This is the well-known Donnan effect. When weak electrolytes are involved, the imbalance includes also hydrogen ions: there is a difference of pH across the boundary and the dissociation of nondiffusible weak electrolytes is suppressed. The effect is very pronounced when the concentration of the weak electrolyte is high and ionic strength is low. The significance of this phenomenon is discussed for polyelectrolyte solutions, and particularly for block copolymer micelles with weak polyelectrolyte shells. The effect is quite dramatic in the latter case.

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