Thermoresponsive poly(2-oxazoline) homopolymers and copolymers in aqueous solutions studied by NMR spectroscopy and dynamic light scattering

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F18%3A00488298" target="_blank" >RIV/61389013:_____/18:00488298 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.eurpolymj.2018.01.019" target="_blank" >http://dx.doi.org/10.1016/j.eurpolymj.2018.01.019</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.eurpolymj.2018.01.019" target="_blank" >10.1016/j.eurpolymj.2018.01.019</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermoresponsive poly(2-oxazoline) homopolymers and copolymers in aqueous solutions studied by NMR spectroscopy and dynamic light scattering

Popis výsledku v původním jazyce

Structural changes during temperature-induced phase transition in D2O solutions of poly(2-ethyl-2-oxazoline) (PEOx) and P(EOx-grad-2-methyl-2-oxazoline (MOx)) copolymers were investigated by 1H NMR methods in combination with dynamic light scattering. NMR spectra showed that in PEOx solutions on molecular level structures formed during gradual heating are preserved during subsequent cooling. Phase transition in solutions of P(EOx-grad-MOx) copolymers as revealed by NMR exists irrespective the solution is turbid or nonturbid at higher temperatures. In contrast to PEOx homopolymers it is very broad, virtually independent of the copolymer composition and molecular weight, and reversible with some hysteresis. Reduced intensities of cross-peaks in NOESY spectra of copolymer solutions at elevated temperatures are mainly due to the changed mobility of copolymer segments. In all investigated solutions two types of water, “free” and “bound” with long and very short spin–spin relaxation times T2, respectively, were detected in the transition region and above the transition. The existence of two T2 components shows that exchange between “bound” and “free” water is slow regarding T2 values.

Název v anglickém jazyce

Thermoresponsive poly(2-oxazoline) homopolymers and copolymers in aqueous solutions studied by NMR spectroscopy and dynamic light scattering

Popis výsledku anglicky

Structural changes during temperature-induced phase transition in D2O solutions of poly(2-ethyl-2-oxazoline) (PEOx) and P(EOx-grad-2-methyl-2-oxazoline (MOx)) copolymers were investigated by 1H NMR methods in combination with dynamic light scattering. NMR spectra showed that in PEOx solutions on molecular level structures formed during gradual heating are preserved during subsequent cooling. Phase transition in solutions of P(EOx-grad-MOx) copolymers as revealed by NMR exists irrespective the solution is turbid or nonturbid at higher temperatures. In contrast to PEOx homopolymers it is very broad, virtually independent of the copolymer composition and molecular weight, and reversible with some hysteresis. Reduced intensities of cross-peaks in NOESY spectra of copolymer solutions at elevated temperatures are mainly due to the changed mobility of copolymer segments. In all investigated solutions two types of water, “free” and “bound” with long and very short spin–spin relaxation times T2, respectively, were detected in the transition region and above the transition. The existence of two T2 components shows that exchange between “bound” and “free” water is slow regarding T2 values.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

<a href="/cs/project/GA15-13853S" target="_blank" >GA15-13853S: Struktury a interakce ve vodných roztocích termoresponsivních polymerů nového typu</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Polymer Journal

ISSN

0014-3057

e-ISSN

—

Svazek periodika

100

Číslo periodika v rámci svazku

March

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

241-252

Kód UT WoS článku

000429760600028

EID výsledku v databázi Scopus

2-s2.0-85041404947