Browsing by Author "Mahanthappa, Mahesh K"
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Item 1D SAXS indexing macro for Igor Pro(2021-09-08) Lindsay, Aaron P; Mueller, Andreas J; Mahanthappa, Mahesh K; Lodge, Timothy P; Bates, Frank S; bates001@umn.edu; Bates, Frank S; UMN Polymer GroupThis code was developed for the facile analysis of 1D SAXS data collected from ordered materials in Igor Pro. A robust file loading algorithm is included, allowing for rapid generation of publication quality stack plots. Also included is a straightforward indexing macro, enabling indexing of 1D SAXS data to a variety of phases. New phases can be added with minimal effort and multiple indexing options are included (e.g., ticks, lines, color, etc.), minimizing time spent analyzing data and producing plots for presentations or publications.Item Data for "Stability of Cubic Single Network Phases in Diblock Copolymer Melts"(2022-07-25) Chen, Pengyu; Mahanthappa, Mahesh K; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research GroupThis dataset contains the self-consistent field theory (SCFT) simulation results and data for geometric analysis in "Stability of cubic single networks in diblock copolymer melts" by Chen et. al. (DOI: 10.1002/pol.20220318). SCFT was used to investigate the stability of cubic single and double network phases. Geometric analysis, including the calculations of mean curvatures and interfacial areas per unit volume of the domain interface, was used to understand the metastability of the single network phases. With this dataset, users should be able to regenerate the calculations and figures that appeared in the paper.Item Data for Surface Relief Terraces in Double Gyroid-Forming Polystyrene-block-Polylactide Thin Films(2023-09-28) Yang, Szu-Ming; Oh, Jinwoo; Magruder, Benjamin R; Kim, HeeJoong; Dorfman, Kevin D; Mahanthappa, Mahesh K; Ellison, Christopher J; cellison@umn.edu; Ellison, Christopher J; University of Minnesota Department of Chemical Engineering and Materials ScienceThis study describes the thin film self-assembly behavior of a polystyrene-block-polylactide (SL-G) diblock copolymer, which undergoes melt self-assembly in bulk into a double gyroid (DG) network phase with a cubic unit cell parameter a = 52.7 nm. Scanning electron microscopy (SEM) and grazing-incidence small-angle X-ray scattering (GISAXS) reveal that thermally annealing 140–198 nm thick copolymer films on SiO2 substrates below the morphological order-to-disorder transition temperature yields polydomain DG structures, in which the (422) planes are oriented parallel to the surface. Bright-field optical microscopy (OM) and atomic force microscopy (AFM) analyses further reveal the film thickness-dependent formation of topographical terraces, including islands, holes, and bicontinuous features. The occurrence of these features sensitively depends on the incommensurability of the as-prepared film thickness and the (211)-interplanar spacing (d211) of the DG unit cell. While the steps heights between adjacent terraces exhibiting characteristic “double wave” patterns of the DG (422) planes coincide with d211, previously unreported transition zones between adjacent terraces are observed wherein “boomerang” and “droplet” patterns are observed. These intermediate patterns follow the expected sequence of adjacent termination planes of the bulk DG unit cell along the [211] direction, as confirmed by comparisons with self-consistent mean-field theory calculations.Item Supporting Data for "From Order to Disorder: Computational Design of Triblock Amphiphiles with 1 nm Domains"(2020-07-06) Shen, Zhengyuan; Chen, Jingyi L; Vernadskaia, Viktoriia; Ertem, S Piril; Mahanthappa, Mahesh K; Hillmyer, Marc A; Reineke, Theresa M; Lodge, Timothy P; Siepmann, J Ilja; siepmann@umn.edu; Siepmann, J Ilja; Materials Research Science & Engineering Center (MRSEC)Data including input/output and restart files for all the systems, analysis codes (python, fortran, cpp), and figures in the paper "From Order to Disorder: Computational Design of Triblock Amphiphiles with 1 nm Domains." Sample molecular dynamics trajectories pieces are provided due to the extremely long simulation trajectories.Item Supporting Data for Self-Assembly of Unusually Stable Thermotropic Network Phases by Cellobiose-Based Guerbet Glycolipids(2024-04-08) Das, Soumi; Zheng, Caini; Calabrese, Michelle A; Reineke, Theresa M; Siepmann, Ilja J; Mahanthappa, Mahesh K; Lodge, Timothy P; treineke@umn.edu; Reineke, Theresa M; University of MinnesotaThese files contain data along with associated output from instrumentation supporting all results reported in the referenced paper. Bicontinuous thermotropic liquid crystal (LC) materials, such as double gyroid (DG) phases, are highly promising for various applications due to their intricate 3D network structures. However, the lack of robust molecular design rules for shape-filling amphiphiles hinders their utility. To address this, we synthesized cellobiose-based glycolipids with Guerbet-type branched alkyl tails and examined their thermotropic LC self-assembly. Through techniques including differential scanning calorimetry (DSC), polarized optical microscopy (POM), and small-angle X-ray scattering (SAXS), we found that Guerbet cellobiosides have a strong propensity to form DG morphology across broad thermotropic phase ranges. The stability of these assemblies depends on the alkyl tail structure and anomeric configuration of the glycolipid in a previously unrecognized manner. Molecular simulations provide further insights, revealing molecular motifs crucial for network phase self-assembly, paving the way for future designs and applications of network LC materials.Item Wigner-Seitz Cell generation and calculations in MATLAB(2021-09-08) Lindsay, Aaron P; Mueller, Andreas J; Mahanthappa, Mahesh K; Lodge, Timothy P; Bates, Frank S; bates001@umn.edu; Bates, Frank S; UMN Polymer GroupThis series of MATLAB codes was developed to generate publication-quality Wigner-Seitz cells for a variety of structures. These are frequently desired for self-assembled micellar systems, wherein the geometry of the Wigner-Seitz cell plays a role in the emergence of several packings. The main algorithm (VoronoiTesselation.m) is generalized, allowing specification of lattice positions and parameters or the upload of these values from a .xtl file exported from Vesta. Added is the ability to determine various cell parameters, including the coordination number, area/volume, and the second-moment volume, which is proportional to the stretching moment for polymer chains stretched from the cell center to the cell edges. A simple algorithm for simulation of 2D diffraction patterns is also included (diffraction.m).