Characterization of Polyisoprene-b-Poly(methyl methacrylate) Diblock Copolymer Micelles in Acetonitrile
Schillén, Karin LU
; Yekta, Ahmad
; Ni, Shaoru
; Farinha, Jose Paulo S.
and Winnik, Mitchell A.
(1999)
In The Journal of Physical Chemistry Part B
103(43).
p.9090-9103
- Abstract
- In acetonitrile, polyisoprene-b-poly(methyl methacrylate) (PI−PMMA) diblock copolymers form starlike micelles with a dense core of the insoluble PI blocks and a soft solvent-swollen corona of the soluble PMMA blocks. Static and dynamic light scattering experiments in combination with viscosity measurements show that these micelles behave hydrodynamically as hard spheres. The block copolymers are labeled at the block junction, with a single fluorescent dye, either a donor chromophore (phenanthrene) or an acceptor chromophore (anthracene). These dyes are confined to the interface during self-assembly. Fluorescence energy-transfer experiments on molecularly mixed micelles of donor- and acceptor-labeled copolymers provide a core radius of 7.6... (More)
- In acetonitrile, polyisoprene-b-poly(methyl methacrylate) (PI−PMMA) diblock copolymers form starlike micelles with a dense core of the insoluble PI blocks and a soft solvent-swollen corona of the soluble PMMA blocks. Static and dynamic light scattering experiments in combination with viscosity measurements show that these micelles behave hydrodynamically as hard spheres. The block copolymers are labeled at the block junction, with a single fluorescent dye, either a donor chromophore (phenanthrene) or an acceptor chromophore (anthracene). These dyes are confined to the interface during self-assembly. Fluorescence energy-transfer experiments on molecularly mixed micelles of donor- and acceptor-labeled copolymers provide a core radius of 7.6 ± 0.8 nm and a number-average aggregation number ( ) of 98 ± 22 under the assumption that the energy transfer takes place on a surface of a sphere. Simulations in terms of a Helfand−Tagami junction distribution profile confirm that the core−corona interface of the PI−PMMA micelles is thin (ca. 0.9 nm) and that almost all of the energy transfer occurs within a narrow interfacial region. From the static light scattering measurements of the mixed micelles a weight-average aggregation number ( ) of 127 ± 6 is obtained. The ratio / = 1.3 agrees with size polydispersity of the micelles obtained from the analysis of dynamic light scattering data. The experimental corona thicknesses are in good agreement with those calculated from expressions describing starlike block copolymer micelles. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1736882
- author
- Schillén, Karin
LU
; Yekta, Ahmad
; Ni, Shaoru
; Farinha, Jose Paulo S.
and Winnik, Mitchell A.
- organization
- publishing date
- 1999
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The Journal of Physical Chemistry Part B
- volume
- 103
- issue
- 43
- pages
- 9090 - 9103
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:0000786269
- ISSN
- 1520-5207
- DOI
- 10.1021/jp990251y
- language
- English
- LU publication?
- yes
- id
- c9239175-54e0-4b34-a63b-4304b2cddddd (old id 1736882)
- date added to LUP
- 2016-04-01 15:35:08
- date last changed
- 2022-01-28 06:05:36
@article{c9239175-54e0-4b34-a63b-4304b2cddddd,
abstract = {{In acetonitrile, polyisoprene-b-poly(methyl methacrylate) (PI−PMMA) diblock copolymers form starlike micelles with a dense core of the insoluble PI blocks and a soft solvent-swollen corona of the soluble PMMA blocks. Static and dynamic light scattering experiments in combination with viscosity measurements show that these micelles behave hydrodynamically as hard spheres. The block copolymers are labeled at the block junction, with a single fluorescent dye, either a donor chromophore (phenanthrene) or an acceptor chromophore (anthracene). These dyes are confined to the interface during self-assembly. Fluorescence energy-transfer experiments on molecularly mixed micelles of donor- and acceptor-labeled copolymers provide a core radius of 7.6 ± 0.8 nm and a number-average aggregation number ( ) of 98 ± 22 under the assumption that the energy transfer takes place on a surface of a sphere. Simulations in terms of a Helfand−Tagami junction distribution profile confirm that the core−corona interface of the PI−PMMA micelles is thin (ca. 0.9 nm) and that almost all of the energy transfer occurs within a narrow interfacial region. From the static light scattering measurements of the mixed micelles a weight-average aggregation number ( ) of 127 ± 6 is obtained. The ratio / = 1.3 agrees with size polydispersity of the micelles obtained from the analysis of dynamic light scattering data. The experimental corona thicknesses are in good agreement with those calculated from expressions describing starlike block copolymer micelles.}},
author = {{Schillén, Karin and Yekta, Ahmad and Ni, Shaoru and Farinha, Jose Paulo S. and Winnik, Mitchell A.}},
issn = {{1520-5207}},
language = {{eng}},
number = {{43}},
pages = {{9090--9103}},
publisher = {{The American Chemical Society (ACS)}},
series = {{The Journal of Physical Chemistry Part B}},
title = {{Characterization of Polyisoprene-b-Poly(methyl methacrylate) Diblock Copolymer Micelles in Acetonitrile}},
url = {{http://dx.doi.org/10.1021/jp990251y}},
doi = {{10.1021/jp990251y}},
volume = {{103}},
year = {{1999}},
}