Self-Organization in Dilute Aqueous Solutions of Thermoresponsive Star-Shaped Six-Arm Poly-2-Alkyl-2-Oxazines and Poly-2-Alkyl-2-Oxazolines

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Kirila , T , Smirnova , A , Aseyev , V , Tenkovtsev , A , Tenhu , H & Filippov , A 2021 , ' Self-Organization in Dilute Aqueous Solutions of Thermoresponsive Star-Shaped Six-Arm Poly-2-Alkyl-2-Oxazines and Poly-2-Alkyl-2-Oxazolines ' , Polymers , vol. 13 , no. 9 , 1429 . https://doi.org/10.3390/polym13091429

Title: Self-Organization in Dilute Aqueous Solutions of Thermoresponsive Star-Shaped Six-Arm Poly-2-Alkyl-2-Oxazines and Poly-2-Alkyl-2-Oxazolines
Author: Kirila, Tatyana; Smirnova, Anna; Aseyev, Vladimir; Tenkovtsev, Andrey; Tenhu, Heikki; Filippov, Alexander
Contributor: University of Helsinki, Department of Chemistry
University of Helsinki, Department of Chemistry
Date: 2021-05
Language: eng
Number of pages: 15
Belongs to series: Polymers
ISSN: 2073-4360
URI: http://hdl.handle.net/10138/330253
Abstract: The behavior of star-shaped six-arm poly-2-alkyl-2-oxazines and poly-2-alkyl-2-oxazolines in aqueous solutions on heating was studied by light scattering, turbidimetry and microcalorimetry. The core of stars was hexaaza [2(6)] orthoparacyclophane and the arms were poly-2-ethyl-2-oxazine, poly-2-isopropyl-2-oxazine, poly-2-ethyl-2-oxazoline, and poly-2-isopropyl-2-oxazoline. The arm structure affects the properties of polymers already at low temperatures. Molecules and aggregates were present in solutions of poly-2-alkyl-2-oxazines, while aggregates of two types were observed in the case of poly-2-alkyl-2-oxazolines. On heating below the phase separation temperature, the characteristics of the investigated solutions did not depend practically on temperature. An increase in the dehydration degree of poly-2-alkyl-2-oxazines and poly-2-alkyl-2-oxazolines led to the formation of intermolecular hydrogen bonds, and aggregation was the dominant process near the phase separation temperature. It was shown that the characteristics of the phase transition in solutions of the studied polymer stars are determined primarily by the arm structure, while the influence of the molar mass is not so significant. In comparison with literature data, the role of the hydrophobic core structure in the formation of the properties of star-shaped polymers was analyzed.
Subject: thermoresponsive star-shaped polymers
poly-2-alkyl-2-oxazines and poly-2-alkyl-2-oxazolines
aqueous solutions
light scattering
turbidimetry
microcalorimetry
phase separation
aggregation
CYCLIC IMINO ETHERS
BLOCK-COPOLYMERS
AGGREGATION BEHAVIOR
POLY(2-ISOPROPYL-2-OXAZOLINE)
POLY(2-OXAZOLINE)S
POLYMERIZATION
POLYMERS
CORE
CONFORMATION
POLYSTYRENE
116 Chemical sciences
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