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Temperature behavior of aqueous solutions of poly(2-oxazoline) homopolymer and block copolymers investigated by NMR spectroscopy and dynamic light scattering
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SYSNO ASEP 0531870 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Temperature behavior of aqueous solutions of poly(2-oxazoline) homopolymer and block copolymers investigated by NMR spectroscopy and dynamic light scattering Author(s) Konefal, Rafal (UMCH-V) RID, ORCID
Černoch, Peter (UMCH-V) RID, ORCID
Konefal, Magdalena (UMCH-V) ORCID, RID
Spěváček, Jiří (UMCH-V) RID, ORCIDArticle number 1879 Source Title Polymers. - : MDPI
Roč. 12, č. 9 (2020), s. 1-16Number of pages 16 s. Language eng - English Country CH - Switzerland Keywords thermoresponsive polymer ; poly(2-ethyl-2-oxazoline) ; poly(2-isopropyl-2-oxazoline) Subject RIV CD - Macromolecular Chemistry OECD category Polymer science R&D Projects GA15-13853S GA ČR - Czech Science Foundation (CSF) GA18-12925S GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support UMCH-V - RVO:61389013 UT WOS 000581299500001 EID SCOPUS 85090567195 DOI 10.3390/polym12091879 Annotation 1H NMR methods in combination with dynamic light scattering were applied to study temperature behavior of poly(2-isopropyl-2-oxazoline) (PIPOx) homopolymer as well as PIPOx-b-poly(2-methyl-2-oxazoline) (PMeOx) and poly(2-ethyl-2-oxazoline) (PEtOx)-b-PMeOx diblock copolymers in aqueous solutions. 1H NMR spectra showed a different way of phase transition for the main and side chains in PIPOx-based solutions. Additionally, the phase transition is irreversible for PIPOx homopolymer and partially reversible for PIPOx-b-PMeOx copolymer. As revealed by NMR, the phase transition in PEtOx-based copolymers solutions exists despite the absence of solution turbidity. It is very broad, virtually independent of the copolymer composition and reversible with some hysteresis. Two types of water molecules were detected in solutions of the diblock copolymers above the phase transition—“free” with long and “bound” with short spin–spin relaxation times T2. NOESY spectra revealed information about conformational changes observed already in the pre-transition region of PIPOx-b-PMeOx copolymer solution. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2021 Electronic address https://www.mdpi.com/2073-4360/12/9/1879
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