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Crystallization-induced switching of the morphology of poly(ethylene oxide)-block-polybutadiene micelles

Title data

Mihut, Adriana M. ; Chiche, Arnaud ; Drechsler, Markus ; Schmalz, Holger ; di Cola, Emanuela ; Krausch, Georg ; Ballauff, Matthias:
Crystallization-induced switching of the morphology of poly(ethylene oxide)-block-polybutadiene micelles.
In: Soft Matter. Vol. 5 (2009) Issue 1 . - pp. 208-213.
ISSN 1744-6848
DOI: https://doi.org/10.1039/b810415h

Official URL: Volltext

Project information

Project financing: Deutsche Forschungsgemeinschaft
European Community's "Marie-Curie Actions", Grant Number MRTN-CT-2004-504052

Abstract in another language

We studied the morphology of micelles formed by a well-defined poly(1,2-butadiene)-block-poly( ethylene oxide) diblock copolymer (PB-b-PEO). Dissolved in n-heptane at 70 degrees C, that is, above the melting point of PEO, spherical micelles are formed due to the selectivity of the solvent for the PB-block. If the solutions are cooled down to low temperatures, the liquid PEO-block crystallizes within the cores of the spherical micelles that remain stable. If, however, the solutions are quenched to 30 degrees C, the spherical micelles aggregate to a novel meander-like structure within several minutes. In its final state, the meander-like super-structure is crystalline, as revealed by time-resolved wide-angle X-ray scattering. The super-structure is shown to result from crystallization-induced aggregation of spherical micelles. Moreover, crystallization leads to well-defined angles between subsequent aggregating units. A quantitative Avrami-type analysis of the crystallization kinetics demonstrates that the formation of the meander-type structure resembles a 2D growth process combined with a breakout crystallization, showing an Avrami-exponent of 2.5. In contrast to this, crystallization at low temperatures resembles a confined crystallization with a low Avrami-exponent of 0.7. All data demonstrate that the morphology of block copolymers having a crystallizable block can be switched by the competition of aggregation and crystallization.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: BLOCK-COPOLYMER MICELLES; TRANSMISSION ELECTRON-MICROSCOPY; DIBLOCK COPOLYMERS; SELECTIVE SOLVENT; DILUTE-SOLUTION; DRUG-DELIVERY; TRIBLOCK COPOLYMERS; ETHYLENE-OXIDE; VESICLES; TRANSITION
Institutions of the University: Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry II
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry II > Chair Macromolecular Chemistry II - Univ.-Prof. Dr. Andreas Greiner
Profile Fields
Profile Fields > Advanced Fields
Profile Fields > Advanced Fields > Polymer and Colloid Science
Research Institutions > Research Centres > Bayreuth Institute of Macromolecular Research - BIMF
Research Institutions > Research Centres > Bayreuth Center for Colloids and Interfaces - BZKG
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 15 Apr 2015 06:24
Last Modified: 01 Mar 2017 13:31
URI: https://eref.uni-bayreuth.de/id/eprint/10085