de Pablo Group: Su-mi Hur

Postdoctoral Research Scholar

de Pablo Group

Contact

  • Phone
    773.834.2912
  • Address

    Searle Laboratory 105

    5735 South Ellis Avenue

    Chicago, IL 60637

  • Email
    sumi at uchicago.edu

Research

Solvent annealing has gained interest as a strategy for controlling the self-assembly of block copolymer films, which has attracted attention as a promising high-resolution lithographic tool. Different from thermal annealing, solvent annealing decreases the risk of thermal degradation due to its low processing temperature. Thus enabling use of block copolymers with greater chemical diversity. Moreover, solvent annealing provides opportunities to create structures that cannot be achieved by thermal annealing. Phase-separated morphologies of block copolymer are significantly affected by process conditions such as solvent type and solvent vapor pressure etc. However, the current theoretical understanding of solvent annealing processes is limited and experimental conditions are found by trial-and-error. Our research goal is to develop an efficient simulation tool for solvent annealed block copolymer films to study the evolution of microstructure and the transformations between various phases in response to solvent swelling and evaporation.

Our new particle based coarse-grained model successfully reproduces phase behavior of polymer solutions in the bulk, and also incorporates the solvent vapor phase at equilibrium with solvated polymer films. This approach enables description of important physics at the free surface of the film that interacts with the solvent vapor. Moreover, the model is able to properly mimic the experimental procedure of solvent annealing while accessing the large length and time scales relevant to applications in directed self-assembly. Currently, we are developing a method to incorporate proper dynamics of the process in the model and studying the effects of solvent-polymer interactions, solvent vapor pressure and solvent evaporation rate on the morphology of ordered domains.

Biography

Su-Mi Hur obtained her BS and MS degrees in chemical engineering department at Seoul National University in South Korea. For her MS degree, she developed a control algorithm, Model-on-Demand Model Predictive Control and applied it to a semi-batch copolymerization reactor advised by Prof. Hyun-ku Rhee. She shifted her interest to polymer physics and received her PhD from the Chemical Engineering department at the University of California, Santa Barbara, under the supervision of Prof. Glenn H. Fredrickson in 2012. During her graduate studies, her research focused on developing improved block copolymer lithography techniques by means of self-consistent field theory (SCFT) simulations. She has developed a powerful suite of field-based computer simulation tools for exploring the self-assembly of complex polymeric fluids under confinement and have studied various polymeric systems. Su-Mi has also extended directed self-assembly methods to mixed polymer brushes and demonstrated that lateral confinement and grafting density modulation can induce technologically attractive lateral phase separation.

Su-Mi Hur received an IBM PhD fellowship in two years (2009, 2010). As a part of the fellowship program, she interned at IBM Almaden Research Center, San Jose guided by an IBM mentor Dr. Jed Pitera. She was awarded the 2010 Doh Wonsuk Memorial Award given by the Korean Institute of Chemical Engineering US Chapter to the best Korean PhD student who studies chemical engineering related area in USA.

She continued her research career as a postdoctoral associate in Prof. Juan de Pablo’s group at University of Wisconsin-Madison, and moved to IME at the University of Chicago along with the group. Her current research project is developing an efficient model for solvent assisted directed self-assembly in block copolymer thin film.

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