title: Thickness dependent effective viscosity of a polymer solution near an interface probed by a quartz crystal microbalance with dissipation method.
abstract: The solution viscosity near an interface, which affects the solution behavior and the molecular dynamics in the solution, differs from the bulk. This paper measured the effective viscosity of a dilute poly (ethylene glycol) (PEG) solution adjacent to a Au electrode using the quartz crystal microbalance with dissipation (QCM-D) technique. We evidenced that the effect of an adsorbed PEG layer can be ignored, and calculated the zero shear rate effective viscosity to remove attenuation of high shear frequency oscillations. By increasing the overtone n from 3 to 13, the thickness of the sensed polymer solution decreased from ~70 to 30 nm. The zero shear rate effective viscosity of the polymer solution and longest relaxation time of PEG chains within it decrease with increasing solution thickness. The change trends are independent of the relation between the apparent viscosity and shear frequency and the values of the involved parameter, suggesting that the polymer solution and polymer chains closer to a solid substrate have a greater effective viscosity and slower relaxation mode, respectively. This method can study the effect of an interface presence on behavior and phenomena relating to the effective viscosity of polymer solutions, including the dynamics of discrete polymer chains.
authors: Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
authors: Jiajie
authors: J
authors: Fang
authors: Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
authors: Tao
authors: T
authors: Zhu
authors: 1] Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2] School of Electronics and Information and College of Chemistry and Biological Science, Yi Li Normal University, Yining 835000, China.
authors: Jie
authors: J
authors: Sheng
authors: 1] Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2] School of Electronics and Information and College of Chemistry and Biological Science, Yi Li Normal University, Yining 835000, China.
authors: Zhongying
authors: Z
authors: Jiang
authors: 1] Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2] Laboratory of Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China.
authors: Yuqiang
authors: Y
authors: Ma