Molecular-level changes of aqueous poly(N-isopropylacrylamide) in phase transition

I Juurinen (Corresponding Author), S Galambosi, Adina Anghelescu-Hakala, J Koskelo, V Honkimäki, K Hämäläinen, S Huotari, M Hakala (Corresponding Author)

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    Abstract

    We report a Compton scattering study on the molecular-level structural changes of aqueous poly(N-isopropylacrylamide) (PNIPAM) across the conformational phase transition. PNIPAM is a thermoresponsive polymer that changes its conformation in water from the hydrophilic coil state to the collapsed hydrophobic globule state at 32 °C. Combined with density functional theory calculations, the Compton scattering experiments detect two type of changes in the phase transition. The amount of hydrogen bonds is found to reduce, and an elongation of the internal covalent bond lengths is observed. The elongation of the bonds indicates that not only the hydrogen bonding changes but there are other processes, most likely related to hydrophobic interaction, that should be taken into account in the phase transition.
    Original languageEnglish
    Pages (from-to)5518-5523
    Number of pages6
    JournalThe Journal of Physical Chemistry B
    Volume118
    Issue number20
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

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    Juurinen, I., Galambosi, S., Anghelescu-Hakala, A., Koskelo, J., Honkimäki, V., Hämäläinen, K., Huotari, S., & Hakala, M. (2014). Molecular-level changes of aqueous poly(N-isopropylacrylamide) in phase transition. The Journal of Physical Chemistry B, 118(20), 5518-5523. https://doi.org/10.1021/jp501913p