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The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends

A series of well-defined (polyisoprene)(2)(polystyrene), I(2)S, single graft copolymers with similar total molecular weights but different compositions, f(PS), were blended with a low molecular weight polyisoprene homopolymer matrix at a constant concentration 2 wt%, and the micellar characteristics...

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Autores principales: Pavlopoulou, Eleni, Chrissopoulou, Kiriaki, Pispas, Stergios, Hadjichristidis, Nikos, Anastasiadis, Spiros H.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7967213/
https://www.ncbi.nlm.nih.gov/pubmed/33803241
http://dx.doi.org/10.3390/polym13050833
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author Pavlopoulou, Eleni
Chrissopoulou, Kiriaki
Pispas, Stergios
Hadjichristidis, Nikos
Anastasiadis, Spiros H.
author_facet Pavlopoulou, Eleni
Chrissopoulou, Kiriaki
Pispas, Stergios
Hadjichristidis, Nikos
Anastasiadis, Spiros H.
author_sort Pavlopoulou, Eleni
collection PubMed
description A series of well-defined (polyisoprene)(2)(polystyrene), I(2)S, single graft copolymers with similar total molecular weights but different compositions, f(PS), were blended with a low molecular weight polyisoprene homopolymer matrix at a constant concentration 2 wt%, and the micellar characteristics were studied by small-angle x-ray scattering. To investigate the effect of macromolecular architecture on the formation and characteristics of micelles, the results on the single graft copolymers were compared with those of the corresponding linear polystyrene-b-polyisoprene diblock copolymers, SI. The comparison reveals that the polystyrene core chains are more stretched in the case of graft copolymer micelles. Stretching turned out to be purely a result of the architecture due to the second polyisoprene block in the corona. The micellization of a (polystyrene)(2)(polyisoprene), S(2)I, graft copolymer was also studied, and the comparison with the results of the corresponding I(2)S and SI copolymers emphasizes the need for a critical core volume rather than a critical length of the core-forming block, in order to have stable micelles. Finally, the absence of micellization in the case of the I(2)S copolymer with the highest polystyrene volume fraction is discussed. For this sample, macrophase separation occurs, with polyisoprene cylinders formed in the copolymer-rich domains of the phase-separated blends.
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spelling pubmed-79672132021-03-18 The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends Pavlopoulou, Eleni Chrissopoulou, Kiriaki Pispas, Stergios Hadjichristidis, Nikos Anastasiadis, Spiros H. Polymers (Basel) Article A series of well-defined (polyisoprene)(2)(polystyrene), I(2)S, single graft copolymers with similar total molecular weights but different compositions, f(PS), were blended with a low molecular weight polyisoprene homopolymer matrix at a constant concentration 2 wt%, and the micellar characteristics were studied by small-angle x-ray scattering. To investigate the effect of macromolecular architecture on the formation and characteristics of micelles, the results on the single graft copolymers were compared with those of the corresponding linear polystyrene-b-polyisoprene diblock copolymers, SI. The comparison reveals that the polystyrene core chains are more stretched in the case of graft copolymer micelles. Stretching turned out to be purely a result of the architecture due to the second polyisoprene block in the corona. The micellization of a (polystyrene)(2)(polyisoprene), S(2)I, graft copolymer was also studied, and the comparison with the results of the corresponding I(2)S and SI copolymers emphasizes the need for a critical core volume rather than a critical length of the core-forming block, in order to have stable micelles. Finally, the absence of micellization in the case of the I(2)S copolymer with the highest polystyrene volume fraction is discussed. For this sample, macrophase separation occurs, with polyisoprene cylinders formed in the copolymer-rich domains of the phase-separated blends. MDPI 2021-03-09 /pmc/articles/PMC7967213/ /pubmed/33803241 http://dx.doi.org/10.3390/polym13050833 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Pavlopoulou, Eleni
Chrissopoulou, Kiriaki
Pispas, Stergios
Hadjichristidis, Nikos
Anastasiadis, Spiros H.
The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title_full The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title_fullStr The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title_full_unstemmed The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title_short The Micellization of Well-Defined Single Graft Copolymers in Block Copolymer/Homopolymer Blends
title_sort micellization of well-defined single graft copolymers in block copolymer/homopolymer blends
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7967213/
https://www.ncbi.nlm.nih.gov/pubmed/33803241
http://dx.doi.org/10.3390/polym13050833
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