A5071370858- Block Copolymer Self-Assembly
- Advanced Polymer Synthesis and Characterization
- Polymer crystallization and properties
- Polymer Nanocomposites and Properties
- Electrostatics and Colloid Interactions
- Phase Change Materials Research
- Surfactants and Colloidal Systems
- Material Dynamics and Properties
- Advanced Battery Materials and Technologies
- Polymer composites and self-healing
- Advanced Cellulose Research Studies
- Machine Learning in Materials Science
- Rheology and Fluid Dynamics Studies
- Lignin and Wood Chemistry
- Solar-Powered Water Purification Methods
- Additive Manufacturing and 3D Printing Technologies
- Nanopore and Nanochannel Transport Studies
- Organic Electronics and Photovoltaics
- Nuclear Physics and Applications
- Adsorption and Cooling Systems
- Fuel Cells and Related Materials
- Lubricants and Their Additives
- Theoretical and Computational Physics
- Plasma Diagnostics and Applications
- Advanced Physical and Chemical Molecular Interactions
Oak Ridge National Laboratory
2015-2024
Government of the United States of America
2023
National Transportation Research Center
2022
University of Tennessee at Knoxville
2016-2021
Georgia Institute of Technology
2021
Oak Ridge Associated Universities
2019
Material Sciences (United States)
2015-2018
Louisiana State University
2016
Center for Nanophase Materials Sciences
2015
National Institute of Standards and Technology
2007
We present a detailed analysis of coarse-grained molecular dynamics simulations semiflexible polymer melts in contact with strongly adsorbing substrate. have characterized the segments interfacial layer by counting number trains, loops, tails, and unadsorbed segments. For more rigid chains, tail an adsorbed segment (a train) dominate while loops are prevalent flexible chains. The tails exhibit nonuniformly stretched conformation akin to "polydisperse pseudobrush" originally envisioned...
The predictive design of flexible and solvent-free polymer electrolytes for solid-state batteries requires an understanding the fundamental principles governing ion transport. In this work, we establish a correlation among composite structures, segmental dynamics, lithium (Li+) transport in ceramic-polymer composite. Elucidating structure-property relationship will allow tailoring Li+ conductivity by optimizing macroscopic electrochemical stability electrolyte. dissociation from slow...
This article reviews current experimental observations and theoretical calculations devoted towards understanding micro-phase separation in charged block copolymer systems. We discuss bulk morphologies melt solution, as well some of the new emerging research directions. Overall, a comprehensive picture is beginning to emerge on fundamental role electrostatics copolymers. provides exciting insight that may be used direct targeted structures endow materials with desired properties can have...
Organic photovoltaics (OPVs) are a topic of extensive research because their potential application in solar cells. Recent work has led to the development coarse-grained model for studying poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blends using molecular simulations. Here we provide further validation force field use it study thermal annealing process P3HT:PCBM blends. A key finding our is that, contrast previous report, does not converge at short time...
Frustration in chain packing has been proposed to play an important role thermodynamic and dynamic properties of polymeric melts glasses. Based on a quantitative analysis using Voronoi tessellations large scale molecular dynamics simulations flexible semi-flexible polymers, we demonstrate that the rigid polymer chains have higher averaged polyhedral volumes significantly wider distribution volume due frustration packing. Using these results, discuss advantage polymers for possible...
Self-assembly and dynamics of a polyelectrolyte (PE)–surfactant complex (PES) are investigated using molecular simulations. The complexation is systematically studied for five different PE backbone charge densities. At fixed surfactant concentration the PES exhibits pearl necklace to agglomerated double spherical structures with chain decorating micelles. counterions do not condense on but released in medium random distribution. relaxation three length scales, polymer chain, segmental,...
Sodium sulfate decahydrate (Na2SO4.10H2O, SSD), a low-cost phase change material (PCM), can store thermal energy. However, separation and unstable energy storage capacity (ESC) limit its use. To address these concerns, eight polymer additives-sodium polyacrylate (SPA), carboxymethyl cellulose (CMC), Fumed silica (SiO2), potassium (PPA), nanofiber (CNF), hydroxyethyl (HEC), dextran sodium (DSS), poly(sodium 4-styrenesulfonate) (PSS)-were used to explore several stabilization mechanisms. The...
The structural and dynamical properties of polymer nanocomposites are investigated using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed in a matrix, the results indicate that polymer-nanoparticle interaction strength overall system temperature primarily responsible for type state (clustering homogeneous dispersion) achieved. A systematic study probing temperature, polymerization, nanoparticle-nanoparticle strengths has been performed. In this paper, however,...
Salt hydrate-based phase-change materials are considered promising for future heat storage applications in residential heating/cooling systems. Smooth phase transition from the liquid to solid and vice versa is essential effective exchanger; however, supercooling salt hydrates delays onset of liquid–solid transition. We investigate molecular level mechanism sodium sulfate decahydrate (SSD). SSD a complex hydrate whose properties governed by electrostatic forces that include pure Coulombic...
The outstanding mechanical properties, light weight, and biodegradability of cellulose nanofibrils (CNFs) make them promising components renewable sustainable next-generation reinforced composite biomaterials bioplastics. Manufacturing CNFs at a pilot scale requires disc-refining fibrillation dilute fibers in aqueous pulp suspensions to shear the apart into their nanodimensional forms, which is, however, an energy-intensive process. Here, we used atomistic molecular dynamics (MD) simulation...
The bulk morphologies formed by a new class of charged block copolymers, 75 vol % fluorinated polyisoprene (FPI) – 25 vol% sulfonated polystyrene (PSS) with 50% sulfonation, are characterized, and the fundamental underlying forces that promote self-assembly processes elucidated. results show how substantially different from their uncharged diblock counterparts (PS-PI) also morphology can be tuned volume fraction casting solvent. A physical understanding based on strong electrostatic...
We report a molecular dynamics simulation investigation of self-assembly and complex formation charged–neutral double hydrophilic hydrophobic–hydrophilic block copolymers (BCP) with oppositely charged surfactants. The structure the surfactant micelles BCP aggregation on micelle surface is systematically studied for five different volume fractions that also mimics reduction concentration. local electrostatic interactions between species encourage core–shell structures where surfactants form...
Liquid crystalline epoxy networks (LCENs) are a class of materials that combine the useful benefits both liquid crystals and exhibiting fascinating thermal, mechanical, stimuli-responsive properties. They have emerged as new platform for developing functional suitable various applications, such sensors, actuators, smart coatings adhesives, tunable optical systems, soft robotics. This article provides an overview LCENs their composites materials, including synthesis characterisation, focusing...
The impact of block connectivity on the morphologies four copolymers varying architecture containing polystyrene (PS) and polyisoprene (PI) has been studied. volume fraction PS molecular weight are held constant while from a linear PS–PI diblock copolymer to three different miktoarm star architectures: PS2PI, PSPI2, PS2PI2. Morphologies PS2PI PSPI2 stars those observed for dependent blocks. change in morphology with indicates that combining two chains at junction point leads chain crowding,...
Understanding how additives interact and segregate within bulk heterojunction (BHJ) thin films is critical for exercising control over structure at multiple length scales delivering improvements in photovoltaic performance. The morphological evolution of poly(3-hexylthiophene) (P3HT) phenyl-C61-butyric acid methyl ester (PCBM) blends that are commensurate with the size a BHJ film examined using petascale coarse-grained molecular dynamics simulations. Comparisons between two-component...
We investigate the effect of high-surface-area self-assembled TiO2:Cu2O nanostructures for CO2 and relative humidity gravimetric detection using polyethylenimine (PEI), 1-ethyl-3-methylimidazolium (EMIM), polyacrylamide (PAAm). Introduction hierarchical on surface quartz crystal microbalance sensors is found to significantly improve sensitivity H2O vapor. The response EMIM increases fivefold 100 nm-thick as compared gold. At ambient concentrations, assembly operates a sensor with excellent...
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTComputer Simulations of Ionomer Self-Assembly and DynamicsMonojoy Goswami, Sanat K. Kumar, Aniket Bhattacharya, Jack F. DouglasView Author Information Department Chemical Engineering, Columbia University, New York, York 10027; Physics, University Central Florida, Orlando, Florida 32816; Polymers Division, National Institutes Standards Technology, Gaithersburg, Maryland 20899 Cite this: Macromolecules 2007,...
Anomalous diffusion of polymer chains in a nanocomposite melt is investigated for different polymer-nanoparticle interaction strengths using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed matrix the results indicate that chain motion exhibits three distinct regions diffusion, Rouse-like motion, an intermediate subdiffusive regime followed by normal Fickian diffusion. The end monomers shows scaling can be attributed to formation strong ``networklike''...
We have synthesized linear ABC triblock terpolymers containing poly(1,3-cyclohexadiene), PCHD, as an end block and characterized their morphologies in the melt. Specifically, we studied polystyrene (PS), polybutadiene (PB), polyisoprene (PI) other blocks. Systematically varying ratio of 1,2- /1,4-microstructures effects conformational asymmetry among three blocks on using transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), self-consistent field theory (SCFT)...