Počet záznamů: 1

Behavior of water during temperature-induced phase separation in poly(vinyl methyl ether) aqueous solutions. NMR and optical microscopy study

  1. 1.
    0358849 - UMCH-V 2012 RIV US eng J - Článek v odborném periodiku
    Spěváček, Jiří - Hanyková, L. - Labuta, J.
    Behavior of water during temperature-induced phase separation in poly(vinyl methyl ether) aqueous solutions. NMR and optical microscopy study.
    Macromolecules. Roč. 44, č. 7 (2011), s. 2149-2153 ISSN 0024-9297
    Grant CEP: GA ČR GA202/09/1281
    Výzkumný záměr: CEZ:AV0Z40500505
    Klíčová slova: phase separation * poly(vinyl methyl ether) * aqueous solution
    Kód oboru RIV: CD - Makromolekulární chemie
    Impakt faktor: 5.167, rok: 2011

    The behavior of water during the temperature-induced phase separation in PVME/D2O solutions was investigated by 1H NMR methods and optical microscopy. A fast exchange between water (HDO) bound in mesoglobules and free water was found from 1H NMR spin−spin relaxation measurements at temperature above the LCST transition for semidilute PVME/D2O solutions where the exchange time is 1.2 ms for c = 6 wt %. In contrast, there is a slow exchange between bound and free water in highly concentrated PVME solutions and the residence time of the bound water 2 s was found for concentrations c = 20−50 wt % using one-dimensional NOE 1H NMR experiment. A 3 order of magnitude slower exchange in highly concentrated PVME/D2O solutions is in accord with our optical microscopy findings that globular-like structures are here approximately 20 times larger than in PVME solution with c = 6 wt %.
    Trvalý link: http://hdl.handle.net/11104/0006410