Browsing by Author "Arora, Akash"

Now showing 1 - 13 of 13
  • Thumbnail Image
    Item
    Data for Order and Disorder in ABCA′ Tetrablock Terpolymers
    (2020-11-16) Radlauer, Madalyn R; Arora, Akash; Matta, Megan E; Bates, Frank S; Hillmyer, Marc A; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Group
  • Thumbnail Image
    Item
    Data from: Accelerating self-consistent field theory of block polymers in a variable unit cell
    (2017-12-04) Arora, Akash; Morse, David C; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D
    The data contain the results of all the SCFT calculations used to demonstrate the performance of the new algorithm that we devised in our paper: https://doi.org/10.1063/1.4986643
  • No Thumbnail Available
    Item
    Data from: Commensurability and finite size effects in lattice simulations of diblock copolymers
    (2015) Arora, Akash; Morse, David; Bates, Frank S; Dorfman, Kevin D
  • No Thumbnail Available
    Item
    Data from: Thermal Processing of Diblock Copolymer Melts Mimics Metallurgy
    (2017-05-22) Kim, Kyungtae; Schulze, Morgan W; Arora, Akash; Lewis III, Ronald M; Hillmyer, Marc A; Dorfman, Kevin D; Bates, Frank S; dorfman@umn.edu; Dorfman, Kevin D
    Small-angle x-ray scattering experiments conducted with compositionally asymmetric low molar mass poly(isoprene)-b-poly(lactide) diblock copolymers reveal an extraordinary thermal history dependence. The development of distinct periodic crystalline or aperiodic quasicrystalline states depends on how specimens are cooled from the disordered state to temperatures below the order-disorder transition temperature. Whereas direct cooling leads to the formation of documented morphologies, rapidly quenched samples that are then heated from low temperature form the hexagonal C14 and cubic C15 Laves phases commonly found in metal alloys. Self-consistent mean-field theory calculations show that these, and other associated Frank-Kasper phases, have nearly degenerate free energies, suggesting that processing history drives the material into long-lived metastable states defined by self-assembled particles with discrete populations of volumes and polyhedral shapes.
  • No Thumbnail Available
    Item
    Examples for Broadly Accessible SCFT
    (Macromolecules, 2016) Arora, Akash; Dorfman, Kevin D
    These are the examples in the publication cited below. They run with the OS-X executable that is also available in the UDC at https://hdl.handle.net/11299/223302 and the output can be analyzed using the polymer visual software at https://hdl.handle.net/11299/223303.
  • No Thumbnail Available
    Item
    Mac OS-X Executable for PSCF
    (Macromolecules, 2016) Arora, Akash; Morse, David C; Dorfman, Kevin D
    This is the PSCF executable referenced in the paper. A link is provided at http://pscf.cems.umn.edu and this deposit is the permanent archive.
  • Thumbnail Image
    Item
    Phase Behavior of Multiblock Polymers: Comparison of Theory and Experiments
    (2017) Pillai, Naveen; Arora, Akash; Dorfman, Kevin D
  • No Thumbnail Available
    Item
    Polymer Visual software for SCFT
    (Polymer, 2018) Pillai, Naveen; Arora, Akash; Dorfman, Kevin D
    This is the version of the polymer visual software that was reported with the cited publication. The most up-to-date version of this program is kept with the PSCF github archive https://github.com/dmorse/pscf maintained by David Morse.
  • No Thumbnail Available
    Item
    Predicting the phase behavior of ABAC tetrablock terpolymers: Sensitivity to Flory-Huggins interaction parameters
    (Polymer, 2018) Arora, Akash; Pillai, Naveen; Bates, Frank S; Dorfman, Kevin D
  • No Thumbnail Available
    Item
    Role of chain length in the formation of Frank-Kasper phases in diblock copolymers
    (2018) Lewis III, Ronald M; Arora, Akash; Beech, Haley K; Lee, Bongjoon; Lindsay, Aaron P; Lodge, Timothy P; Dorfman, Kevin D; Bates, Frank S
  • No Thumbnail Available
    Item
    SCFT Input Files and Free Energy Output for "Stable Frank–Kasper phases of self-assembled, soft matter spheres"
    (Proceedings of the National Academy of Sciences USA, 2018) Reddy, Abhiram; Buckley, Michael B; Arora, Akash; Bates, Frank S; Dorfman, Kevin D; Grason, Gregory M
  • Thumbnail Image
    Item
    Self-assembly of Block Polymers: Self-Consistent Field Theory and Monte-Carlo Simulations
    (2018-05) Arora, Akash
    Block polymers are a class of soft materials that self-assemble at mesoscopic length scales to form a wide variety of ordered structures. The resulting nanostructures have been instrumental in the development of several advanced technologies such as separation membranes and photonic crystals. This thesis focuses on three diverse problems that use self-consistent field theory (SCFT) and Monte Carlo simulations to study the fundamental phase behavior of block polymers. In recent years, several experimental studies have witnessed the formation of complex low-symmetry structures, commonly referred to as Frank–Kasper phases, contain- ing particles of disparate sizes arranged in multiple coordination environments. The first problem of this thesis focuses on examining the stability of various Frank–Kasper phases in AB diblock copolymers. Using SCFT, we computed the free energies of a host of Frank–Kasper phases and observed that the associated free energies differ only marginally (10−3kBT), leading to a rugged free energy surface with many local minima that may be accessible via different nucleation pathways. We have highlighted the significance of these theoretical predictions in the context of two new Frank–Kasper phases discovered experimentally in poly(isoprene)-b-poly(lactide) diblock copolymers. During the course of this project, we have also made a few advancements in the numerical framework of SCFT. Specifically, we have developed a physically informed and robust approach that uses information from experiments to create guess structures of the ordered phases that are required to perform the SCFT calculations. Additionally, we have developed an improved version of the Anderson-mixing iteration algorithm that increases the computational efficiency by at least 5-10 times compared to the previous version. The second problem focuses on studying the phase behavior of three different multiblock polymers, ABC triblocks, ABCA tetrablocks, and ABAC tetrablocks. In each of the cases, we have performed extensive SCFT calculations and compared the resulting predictions with experimental results to further the understanding of experimentally observed morphologies. While investigating the phase behavior of multiblock polymers, we observed that an accurate temperature-dependence of all the involved Flory–Huggins χ parameters is crucial for making any reliable predictions using SCFT. In this context, we have studied the sensitivity of the phase behavior of a specific ABAC-type multiblock, poly(styrene)-b-poly(isoprene)-b-poly(styrene)-b-poly(ethylene oxide) tetrablock terpolymer, towards the set of required χ parameters (χIS,χSO,χIO). In the third problem, we have studied the order–disorder transition of short lamellae- forming diblock copolymers using Monte Carlo simulations. We have developed a systematic approach to accurately estimate the domain spacing of the lamellar structure, and thereby remove the incommensurability and finite-size effects in lattice simulations. This enabled us to precisely determine the order–disorder transition value for short symmetric diblock copolymers.
  • No Thumbnail Available
    Item
    Updated version of polymer visual program
    (2022) Magruder, Benjamin; Arora, Akash; Pillai, Naveen
    This is an update of the polymer visual software. The original version, which was reported in a manuscript (doi: 10.1016/j.polymer.2018.08.07), is available on the UDC at https://hdl.handle.net/11299/223303. The main improvement in the current version of the program is the ability to produce scattering patterns from the SCFT data. The new archive also includes improved commenting to aid new users in taking advantage of the program.