Browsing by Author "Cheong, Guo Kang"
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Item A Computational Approach to the Stability of Complex Sphere Forming Phases in Block Polymer Melts(2021-05) Cheong, Guo KangBlock polymers spontaneously self-assemble into a variety of morphologies upon cooling below their order-disorder temperature. Owing to this behavior, block polymers have various potential applications ranging from semiconductors fabrication to filtration devices. Recent discovery of the stable Frank-Kasper phases in diblock copolymer melts resulted in a shift of focus from high-symmetry morphologies to low-symmetry tetrahedrally close-packed phases. While experimentalists have been able synthesize block polymers that exhibit stable Frank-Kasper phases, they could not predictably determine the observed phases a priori. Computational tools can aid in prediction but are rooted in well-developed theories and experimental results. In this dissertation, we aim to develop theoretical understanding of the stability of Frank-Kasper phases that could aid in prediction through a computational study of block polymers guided by experimental data. To this end, we take a three-pronged approach in the dissertation. First, we examined an experimental diblock copolymer/homopolymer system which produces a variety of Frank-Kasper phases. Our computational study reproduced the salient behavior of the system and unveiled a new mechanism for the stabilization of Frank-Kasper phases. Next, we studied the disordered micelle regime, which has consequence in stabilizing metastable Frank-Kapser phases in thermal processing experiments, for conformationally asymmetric diblock copolymer melts. We uncovered a reduction in the window of stability for the disordered micelle regime with increasing conformationally asymmetric. Finally, we compared computational prediction of binary blends of high molecular weight diblock copolymer to experimental results and demonstrated their utility in accessing Frank-Kasper phases. Along with our analysis, we unveiled a potentially new mechanism that may be important in the stabilization of Frank-Kasper phases. We believe that our work in this dissertation provides additional understanding to the behavior of diblock copolymer, specifically in stabilizing Frank-Kasper phases. This work also opens up potential avenues of interest that may further our ability to tailor block polymers for specific applications.Item Data for "Stability of the Double Gyroid Phase in Bottlebrush Diblock Copolymer Melts"(2021-10-04) Park, So Jung; Cheong, Guo Kang; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research GroupThis data set contains the input and output data files used for the self-consistent field theory simulations in "Stability of the double gyroid phase in bottlebrush diblock copolymer melts" by Park et al. Self-consistent field theory was used to study the self-assembly of bottlebrush block copolymers, focusing on the effect of the bottlebrush architecture on the stability of the double gyroid phase.Item Data for "The disordered micelle regime in a conformationally asymmetric diblock copolymer melt"(2021-10-21) Cheong, Guo Kang; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research GroupData appearing in the publication "The disordered micelle regime in a conformationally asymmetric diblock copolymer melt". This paper reports Monte Carlo Field Theoretic Simulation (MC-FTS) results for diblock copolymers in the sphere-forming region of the phase diagram. The archived data are the post-processed trajectories. Owing to their size, the raw trajectories for the fields are not stored.Item Data from: Evidence for the extended de Gennes regime of a semiflexible polymer in slit confinement(2018) Cheong, Guo Kang; Li, Xiaolan; Dorfman, Kevin DItem Data from: One-parameter scaling theory for DNA extension in a nanochannel(2017) Werner, Erik; Cheong, Guo Kang; Gupta, Damini; Dorfman, Kevin D.; Mehlig, BernhardItem Data from: Wall depletion length of a channel-confined polymer(2017) Cheong, Guo Kang; Li, Xiaolan; Dorfman, Kevin DItem Data supporting: "Symmetry Breaking in Particle-Forming Diblock/Homopolymer Blends"(2020-06-23) Cheong, Guo Kang; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Group