Study of the Kinetics of the Pancake-to-Brush Transition of Poly(N-isopropylacrylamide) Chains
writer：Guangming Liu, He Cheng, Yunfeng Yan, Guangzhao Zhang*
keywords：pancake, brush, pnipam, qcm
source：期刊
specific source：J. Phys. Chem. B 109, 22603-22607, 2005
Issue time：2005年
The chemical grafting of thiol-terminated poly(N-isopropylacrylamide) (HS-PNIPAM) chains to a gold surface from a solution was investigated with a quartz crystal microbalance (QCM) in real time. The frequency and energy dissipation responses revealed that short HS-PNIPAM chains exhibit three-regime kinetics of the grafting. In regimes I and II, the HS-PNIPAM chains form pancake and mushroom structures, respectively. In regime III, the chains form brushes. From regime II to regime III, the mushroom-to-brush transition occurs. For the longer HS-PNIPAM chains, because of the strong segment-surface interaction, the segments cannot desorb from the surface, and the chains do not undergo a pancake-to-brush transition.