Ophelia Tsui

Ophelia Tsui

Office: SCI, Room 215. 617-358-4669
Lab: SCI, Room B2/B3. 617-358-5147
Email:

 

Research Interests:

My research interests encompass several areas of soft condensed matter physics, including the dynamics of polymer nanometer films and nanocomposites, dewetting instability of polymer thin films, wetting properties of textured surfaces, and control of particle trajectories in microfluidics. As atomic force microscopy (AFM) is a major tool in my research, I am also engaged in the development and application of various AFM techniques such as AFM mechanics, nanotribology and nanolithography.

Education:

University of Hong Kong, B. Sc. in Physics (First class honors), Princeton University, Ph. D. in Physics

Representative publications:

  • "Glass Transition Dynamics and Surface Layer Mobility in Unentangled Polystyrene Films", Z. Yang, Y. Fujii, F. K. Lee, C. -H. Lam, O. K. C. Tsui, Science, 328, 1676 (2010).
  • "Wettability of End-Grafted Polymer Brush by Chemically Identical Polymer Films", X. Zhang, F. K. Lee, Ophelia K. C. Tsui, Macromolecules, 41, 8148 (2008).
  • "Variable Liquid Crystal Pretilt Angles by Nanostructured Surfaces", F. S. Y. Yeung, J. Y. Ho, Y. W. Li, F. C. Xie, O. K. C. Tsui, P. Sheng, H. S. Kwok, Appl. Phys. Lett., 88, 051910 (2006).
  • "Liquid Crystal Orientation Transition on Microtextured Substrates", Baoshe Zhang, Fuk Kay Lee, Ophelia K. C. Tsui, Ping Sheng, Phys. Rev. Lett., 91, 215501 (2003).
  • "Study on the Origin of Inverted Phase in Drying Solution-Cast Block Copolymer Films", Haiying Huang, Fajun Zhang, Zhijun Hu, Binyang Du, Tianbai He, Fuk Kay Lee, Yongjian Wang, Ophelia K. C. Tsui, Macromolecules, 36, 4084 (2003).
  • "Effect of C60 Molecular Rotation on Nanotribology", Qi Liang, O. K. C. Tsui, Yabo Xu, Hongnian Li, Xudong Xiao, Phys. Rev. Lett., 90, 146102 (2003).
  • "Effect of Interfacial Interactions on the Glass Transition of Polymer Thin Films", O. K. C. Tsui, T. P. Russell, C.J. Hawker, Macromolecules, 34, 5535 (2001).
  • "Studying Surface Glass-to-Rubber Transition Using Atomic Force Microscopic Adhesion Measurements" O.K.C. Tsui, X. P. Wang, Jacob Y. L. Ho, T. K. Ng, Xudong Xiao, Macromolecules, 33, 4198 (2000).
  • "Sharp Magnetoabsorption Resonances in the Vortex State of Bi2Sr2CaCu2O8+d", Ophelia K. C. Tsui, N. P. Ong, Y. Matsuda, Y. F. Yan and J. B. Peterson, Phys. Rev. Lett. 73, 724 (1994).

 

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Research Descriptions:

Dynamics of Polymer Nanometer Films

It has been broadly observed that the physical properties of polymers, including the elastic modulus, freezing temperature and relaxation behaviors, can become quite different from the bulk when the the material is molded into a nanometer film or structure. Recently, our group developed a method that has enabled us to measure the viscosity of polymer nanometer films with thicknesses from 2 to above 100 nm. In this method, we monitor the dynamics of the height fluctuations of the films and model it with the dynamics of surface capillary waves, which is related to the flow property and hence effective viscosity of the films. Through these measurements, we have made illuminating observations about the rich influences of the interfaces and confinement effect - namely the effect of confining the polymer chains in a dimension smaller than the unperturbed radius of gyration. Having a good understanding of these influences is essential to effective usage of polymers in nanoscale applications.