Small-Angle Neutron Scattering Study of Onion-Type Micelles

Pleštil, J.; Křı́ž, Jaroslav; Tuzar, Zdeněk; Procházka, Karel; Mel’nichenko, Yu. B.; Wígnall, G. D.; Talingting, Maria Ruela; Munk, Peter L.; Webber, S. E.

doi:10.1002/1521-3935(20010201)202:4<553::aid-macp553>3.3.co;2-y

Cited by 19 publications

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“…The obtained value, R c ϭ10.6 nm, is in agreement with results of small-angle neutron scattering experiments. 24 As concerns the number of segments of the shellforming blocks, the value used in simulations differs from that of the experimental sample because of different flexibilities of real and simulated chains. We use the rescaled values of the lattice constant and the effective number of segments, which are mutually coupled as their product equals the contour length of the shell-forming chains.…”

Section: Modelmentioning

confidence: 99%

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

Uhlı́k

Limpouchová

Jelı́nek

et al. 2004

The Journal of Chemical Physics

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Multimolecular micelles, formed by polystyrene-block-poly(methacrylic acid) in water, are studied by lattice Monte Carlo method. Electrostatic interactions are calculated in the mean-field approximation by solving the Poisson-Boltzmann equation. The model is parametrized according to available experimental data. The dependence of micellar size on pH and ionic strength is calculated and compared with experimental data. A special attention is devoted to the behavior in solutions with a low ionic strength.

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Section: Modelmentioning

confidence: 99%

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

Uhlı́k

Limpouchová

Jelı́nek

et al. 2004

The Journal of Chemical Physics

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“…For the micelles with higher aggregation number, the BCA will work even better because the ratio of the self-correlation scattering of the chains to the scattering from the core decreases with increasing aggregation number (see Eq.7). Figure 5 shows the SANS data of polystyrene-block-poly(2vinylpyridine) (PS-b-PVP) copolymer in 0.1 M DCl in D 2 O (Pleštil et al, 1999). The PS-b-PVP copolymer forms micelles with the PS core and protonated (deuterated in D 2 O) PVPD + corona in aqueous media at pH < 4.8.…”

Section: Figurementioning

confidence: 99%

“…In the case of simple micelles, these amplitudes can be calculated. It might be a problem, however, if more complicated micellar systems are studied (onion micelles (Pleštil et al, 1999(Pleštil et al, ), solubilization (K¯íÓ et al, 1996). Using molar masses of the copolymer blocks (M PS = 36.1 × 10 3 g/mol, M PVP = 54.9 × 10 3 g/mol), the excess scattering amplitudes of the blocks were estimated as ∆B s = -2769 (PS) and ∆B c = -3664 × 10 -12 cm (PVPD + ).…”

Section: Conference Papersmentioning

confidence: 99%

“…In such cases, fitting of the theoretical scattering function of polydisperse spherical particles may provide characteristics of the micelle cores. This approach, referred to as Bare-Core Approximation (BCA), has recently been used in studying three-layered (onion type) micelles (Pleštil et al, 1999). The present paper is intended to outline limits of applicability of the approach.…”

Section: Introductionmentioning

confidence: 99%

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Bare-core approximation: a useful approach to SAS data of block copolymer micelles

Pleštil¹

2000

J Appl Cryst

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A middle part of small‐angle scattering curves of block copolymer micelles can frequently be described satisfactorily by the scattering function of homogeneous spherical particles (bare‐core approximation). This makes it possible to easily determine structure characteristics (mean radius, polydispersity, volume, mass) of the micelle core. Thus, information about the internal structure of the core/corona micellar particles can be obtained without using co‐polymers with labelled blocks. Though not universal, this approach is applicable to numerous micellar systems including those formed by hydrogenous copolymers in deuterated solvents. The approach can be also used if the relative excess scattering amplitudes of the core and corona are not a priori known, e.g., in studies of solubilization phenomenon.

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“…We used the core radius R C ϭ12.5 nm determined by low-angle neutron scattering measurements for a similar system of PS-PVP ͓polystyrene-block-poly͑2-vinylpyridine͔͒ micelles with similar composition and association number. 43 This value is a little higher than the estimate based on the density ϭ1.05 g/cm 3 of amorphous PS, FIG. 1.…”

Section: Model and Simulationmentioning

confidence: 60%

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

Uhlı́k

Limpouchová

Jelı́nek

et al. 2003

The Journal of Chemical Physics

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A Monte Carlo simulation for the micellization of ABA-and BAB-type triblock copolymers in a selective solvent. II.Multimolecular micelles in polar solvents formed by polystyrene-block-poly͑methacrylic acid͒ ͑PS-PMA͒, hydrophobically modified by a naphthalene tag between blocks and an anthracene tag at the end of PMA block, are studied by a lattice Monte Carlo method. The model is parametrized according to available experimental data and several structural characteristics of the PMA shell together with the fluorometric decay functions are calculated and compared with results obtained for system without anthracene tags. The hydrophobic tags at the ends of shell-forming blocks try to avoid the polar medium and bury in the shell forcing the chains to loop back. The resulting distribution of traps is bimodal with a smaller peak in the vicinity of the core and a larger one farther from the core than the maximum on the distribution of segments.

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Small-Angle Neutron Scattering Study of Onion-Type Micelles

Cited by 19 publications

References 0 publications

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

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

Bare-core approximation: a useful approach to SAS data of block copolymer micelles

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

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