Contact
    Start Publications Physisorption of Poly(N-isopropylacrylamide) in Its Swollen and ...
    ←  Publication Finder
    QSense

    Physisorption of Poly(N-isopropylacrylamide) in Its Swollen and Collapsed States: Effects of Molecular Conformation and Substrate Interaction

    Year: 2007

    Journal: J. Phys. Chem. C 2007, 111, 18679-18686, 20100827

    Authors: Zhu D-M *†‡, Wu K. †, Wu B. †, Wang P. †, Fang J. †‡, Hou Y., Zhang G.

    Last authors: Guangzhao Zhang

    Organizations: Department of Modern Physics, UniVersity of Science and Technology of China, Hefei, China, 230027, and University of Missouri-Kansas City, Kansas City, Missouri 64110 Department of Physical Chemistry, UniVersity of Science and Technology of China, Hefei, China 230027

    Country: China

    The physisorption and the adsorption kinetics of poly(N-isopropylacrylamide) (PNIPAM) in its swollen and collapsed states on a gold substrate have been studied by a quartz crystal microbalance with dissipation monitoring technique. The adsorption kinetics exhibits exponential behavior following a change of PNIPAM concentration in the solution; the time constant of adsorption decreases with the increase of temperature and the concentration as the polymer is in its swollen state but remains nearly constant in the collapsed state. The growth mode of the adsorbed PNIPAM layer shows different behaviors for the two different states. In the concentration range covered in this study, PNIPAMs in the swollen state form a monolayer only on the gold substrate, while in the collapsed state the polymers may form a multilayer on the same substrate. The different adsorption behaviors in the two states can be explained in terms of the differences in molecular sizes and interactions of the molecules with substrate and solvent molecules.