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159 results on '"Goswami, Monojoy"'

6. Molecular-level design of alternative media for energy-saving pilot-scale fibrillation of nanocellulose.

Author

Shih-Hsien Liu, Rukmani, Shalini J., Mood Mohan, Yan Yu, Vural, Derya, Johnson, Donna A., Copenhaver, Katie, Bhagia, Samarthya, Lamm, Meghan E., Kai Li, Jihua Chen, Goswami, Monojoy, Smith, Micholas Dean, Petridis, Loukas, Ozcan, Soydan, and Smith, Jeremy C.

Subjects
MANUFACTURING processes, HYDROXYL group, HYDROGEN bonding, MOLECULAR dynamics, SMALL molecules, CELLULOSE fibers
Abstract

The outstanding mechanical properties, light weight, and biodegradability of cellulose nanofibrils (CNFs) make them promising components of renewable and sustainable next-generation reinforced composite biomaterials and bioplastics. Manufacturing CNFs at a pilot scale requires disc-refining fibrillation of dilute cellulose fibers in aqueous pulp suspensions to shear the fibers apart into their nanodimensional forms, which is, however, an energy-intensive process. Here, we used atomistic molecular dynamics (MD) simulation to examine media that might facilitate the reduction of interactions between cellulose fibers, thereby reducing energy consumption in fibrillation. The most suitable medium found by the simulations was an aqueous solution with 0.007:0.012 wt.% NaOH:urea, and indeed this was found in pilot-scale experiments to reduce the fibrillation energy by ~21% on average relative to water alone. The NaOH:urea-mediated CNFs have similar crystallinity, morphology, and mechanical strength to those formed in water. The NaOH and urea act synergistically on CNFs to aid fibrillation but at different length scales. NaOH deprotonates hydroxyl groups leading to mesoscale electrostatic repulsion between fibrils, whereas urea forms hydrogen bonds with protonated hydroxyl groups thus disrupting interfibril hydrogen bonds. This suggests a general mechanism in which an aqueous medium that contains a strong base and a small organic molecule acting as a hydrogen-bond acceptor and/or donor may be effectively employed in materials processes where dispersion of deprotonable polymers is required. The study demonstrates how atomic-detail computer simulation can be integrated with pilot-scale experiments in the rational design of materials processes for the circular bioeconomy. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Breakdown of inverse morphologies in charged diblock copolymers

Author

Goswami, Monojoy, Kumar, Rajeev, Sumpter, Bobby G., and Mays, Jimmy

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Brownian Dynamics simulations are carried out to understand the effect of temperature and dielectric constant of the medium on microphase separation of charged-neutral diblock copolymer systems. For different dielectric media, we focus on the effect of temperature on the morphology and dynamics of model charged diblock copolymers. In this study we examine in detail a system of partially charged block copolymer consisting of 75% neutral blocks and 25% of charged blocks with 50% degree of ionization. Our investigations show that due to the presence of strong electrostatic interactions between the charged block and counterions, the block copolymer morphologies are rather different than their neutral counterpart at low dielectric constant, however at high dielectric constant the neutral diblock behaviors are observed. This article highlights the effect of dielectric constant of two different media on different thermodynamic and dynamic quantities. At low dielectric, the morphologies are a direct outcome of the ion-counterion multiplet formation. At high dielectric, these charged diblocks behavior resembles that of neutral and weakly charged polymers with sustainable long-range order. Similar behavior has been observed in chain swelling, albeit with small changes in swelling ratio for large change in polarity of the medium. The results of our simulations agree with recent experimental results and are consistent with recent theoretical predictions of counterion adsorption on flexible polyelectrolytes.

Published
2011

15. Understanding supercooling mechanism in sodium sulfate decahydrate phase-change material.

Author

Goswami, Monojoy, Kumar, Navin, Li, Yuzhan, Hirschey, Jason, LaClair, Tim J., Akamo, Damilola O., Sultan, Sara, Rios, Orlando, Gluesenkamp, Kyle R., and Graham, Samuel

Subjects
*PHASE change materials, *SODIUM sulfate, *ELECTROSTATIC interaction, *HEAT storage, *MOLECULAR dynamics, *SUPERCOOLING, *POLAR molecules
Abstract

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 phase and vice versa is essential for effective heat exchanger; however, supercooling in salt hydrates delays the onset of liquid–solid phase transition. We investigate the molecular level mechanism of supercooling in sodium sulfate decahydrate (SSD). SSD is a complex salt hydrate whose properties are governed by electrostatic forces that include pure Coulombic interactions as well as hydrogen bonds. Experimentally, we examine the importance of a nucleator in reducing supercooling temperatures. We investigated the effect of various mass concentrations of a borax nucleator on a decrease of supercooling temperatures. Molecular dynamics simulation techniques are used to obtain a basic understanding of supercooling in SSD. We observe that by introducing borax as a nucleator, there is a decrease in the supercooling temperature before nucleation. Our molecular dynamics simulations show that long-range electrostatics between sodium and sulfate ion pairs and that with polar water molecules is responsible for delayed nucleation in SSD that results in supercooling, and also, dynamics of charged molecules slows down. The lack of crystallization leads to amorphous structures in supercooled SSD. [ABSTRACT FROM AUTHOR]

Published
2021
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16. Understanding Interfacial Block Copolymer Structure and Dynamics

Author

Goswami, Monojoy, primary, Iyiola, Oluwagbenga Oare, additional, Lu, Wei, additional, Hong, Kunlun, additional, Zolnierczuk, Piotr, additional, Stingaciu, Laura-Roxana, additional, Heller, William T., additional, Taleb, Omar, additional, Sumpter, Bobby G., additional, and Hallinan, Daniel T., additional

Published
2023
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22. Integrating Advanced Materials Simulation Techniques into an Automated Data Analysis Workflow at the Spallation Neutron Source

Author

Borreguero, Jose M., primary, Campbell, Stuart I., additional, Delaire, Olivier A., additional, Doucet, Mathieu, additional, Goswami, Monojoy, additional, Hagen, Mark E., additional, Lynch, Vickie E., additional, Proffen, Thomas E., additional, Ren, Shelly, additional, Savici, Andrei T., additional, and Sumpter, Bobby G., additional

Published
2014
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29. Liquid crystalline networks based on photo-initiated thiol–ene click chemistry

Author

Li, Yuzhan, primary, Zhang, Yuehong, additional, Goswami, Monojoy, additional, Vincent, Dan, additional, Wang, Liwei, additional, Liu, Tuan, additional, Li, Kai, additional, Keum, Jong K., additional, Gao, Zhenhua, additional, Ozcan, Soydan, additional, Gluesenkamp, Kyle R., additional, Rios, Orlando, additional, and Kessler, Michael R., additional

Published
2020
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30. Self-assembly and structural relaxation in a model ionomer melt.

Author

Goswami, Monojoy, Borreguero, Jose M., and Sumpter, Bobby G.

Subjects
*MOLECULAR dynamics, *MOLECULAR self-assembly, *PERMITTIVITY, *IONOMERS, *POLYMERS, *IONIZATION (Atomic physics), *MOLECULAR structure
Abstract

Molecular dynamics simulations are used to understand the self-assembly and structural relaxation in ionomer melts containing less than 10% degree of ionization on the backbone. The self-assembly of charged sites and counterions shows structural ordering and agglomeration with a range of structures that can be achieved by changing the dielectric constant of the medium. The intermediate scattering function shows a decoupling of charge and counterion relaxation at longer length scales for only high dielectric constant and at shorter length scales for all dielectric constants. Overall, the slow structural decay of counterions in the strongly correlated ionomer system closely resembles transport properties of semi-flexible polymers. [ABSTRACT FROM AUTHOR]

Published
2015
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37. Studies on the 3-Lamellar Morphology of Miktoarm Terpolymers

Author

Kim, Hyeyoung, primary, Arras, Matthias M. L., additional, Mahalik, J. P., additional, Wang, Weiyu, additional, Yu, Duk Man, additional, Chernyy, Sergey, additional, Goswami, Monojoy, additional, Kumar, Rajeev, additional, Sumpter, Bobby G., additional, Hong, Kunlun, additional, Smith, Gregory S., additional, and Russell, Thomas P., additional

Published
2018
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38. Effect of polymer-filler interaction strengths on the thermodynamic and dynamic properties of polymer nanocomposites.

Author

Goswami, Monojoy and Sumpter, Bobby G.

Subjects
*POLYMERS, *NANOPARTICLES, *CLUSTERING of particles, *POLYMERIZATION, *THERMODYNAMICS
Abstract

The structural and dynamical properties of polymer nanocomposites are investigated using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed in a polymer matrix, the results indicate that the polymer-nanoparticle interaction strength and the overall system temperature are primarily responsible for the type of dispersed state (clustering and homogeneous dispersion) achieved. A systematic study probing temperature, polymerization, and polymer-nanoparticle and nanoparticle-nanoparticle interaction strengths has been performed. In this paper, however, we focus the discussion on the results for varying polymer-nanoparticle interaction strengths at different temperatures. By examining the structure and dynamics, we show that there are two kinds of “clustering transitions:” one due to thermodynamic and another due to the dynamical response of the system. From these results, a representative phase diagram is developed that captures the entire simulated space and allows the easy identification of the highly dispersed and the clustered states. [ABSTRACT FROM AUTHOR]

Published
2009
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39. Distributed workflows for modeling experimental data

Author

Lynch, Vickie E., primary, Calvo, Jose Borreguero, additional, Deelman, Ewa, additional, da Silva, Rafael Ferreira, additional, Goswami, Monojoy, additional, Hui, Yawei, additional, Lingerfelt, Eric, additional, and Vetter, Jeffrey S., additional

Published
2017
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42. Method To Synthesize Micronized Spherical Carbon Particles from Lignin

Author

Ho, Hoi Chun, Bonnesen, Peter V., Nguyen, Ngoc A., Cullen, David A., Uhrig, David, Goswami, Monojoy, Keum, Jong K., and Naskar, Amit K.

Abstract

Spherical carbon particles are versatile products that are of interest in polymer modification and scaffolding, catalysis, and energy storage applications. Despite various complex synthesis methods available currently, there is a need for simplified synthesis techniques to develop spherical carbon particles from sustainable feedstock. Here, we report a simple method for manufacturing micronized carbon particles from lignin, a plant biomass derived phenolic oligomer. By careful selection of a good, high boiling solvent that can fully solvate and stabilize lignin, we were able to create spherical free-flowing carbon particles from lignin by a simple solvothermal process and subsequent carbonization. During solvothermal reaction, lignin degrades into fragments via its thermally sensitive bonds. Simultaneously, the residual lignin and its fragments repolymerize, condense into highly cross-linked structures, and eventually precipitate out of solution with a spherical shape. Infrared and NMR spectroscopy data in combination with the rheological properties of thermally condensed, solvated oligomer elucidate evolution in the chemical architecture of lignin. The coarse-grained molecular dynamics simulations revealed the growth of spherical char from lignin in a good solvent through intermolecular condensation. X-ray diffraction and electron microscopy data show the morphology of the carbonized product—an increase in the carbonization temperature enhances the structural order.

Published
2020
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43. Bibliometric review and recent advances in total scattering pair distribution function analysis: 21 years in retrospect

Author

Akamo, Damilola O., Ijaola, Ahmed Olanrewaju, George, Toyosi T., Page, Katharine, Keffer, David J., Li, Yuzhan, Goswami, Monojoy, LaClair, Tim J., Gluesenkamp, Kyle, and Rios, Orlando

Abstract

AbstractGlobal research activities have been driven by the quest to develop and characterize novel materials for technological advancements. The total scattering pair distribution function (TSPDF) is a powerful and versatile characterization technique for examining the structural details of diverse complex materials including liquid, amorphous, disordered crystalline, and nanostructured materials. Thus, it is critical to keep track of research progress, identify research gaps, and future research directions of the application of the TSPDF technique in materials development and discovery. In this work, a bibliometric analysis of literature regarding the TSPDF technique between 2000 and 2021 was conducted using datasets retrieved from the Web of Science database. The research trends based on publication outputs, research subject distribution, co-authorships among institutions, countries/regions, co-citation of referenced sources, and keyword co-occurrence are evaluated and discussed herein. The impact of the TSPDF technique is projected to increase due to its importance in probing emerging functional materials, and the advances in specialized facilities and instrumentation among the scientific communities engaged with it. Finally, current and emerging research hotspots related to TSPDF technique such as catalysis, computer modeling and simulation, pharmaceutics, machine learning, hydrogen storage, battery materials, and layered structured materials are also identified and discussed.

Published
2023
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49. Morphologies of ABC Triblock Terpolymer Melts Containing Poly(Cyclohexadiene): Effects of Conformational Asymmetry

Author

Kumar, Rajeev, primary, Sides, Scott W., additional, Goswami, Monojoy, additional, Sumpter, Bobby G., additional, Hong, Kunlun, additional, Wu, Xiaodong, additional, Russell, Thomas P., additional, Gido, Samuel P., additional, Misichronis, Konstantinos, additional, Rangou, Sofia, additional, Avgeropoulos, Apostolos, additional, Tsoukatos, Thodoris, additional, Hadjichristidis, Nikos, additional, Beyer, Frederick L., additional, and Mays, Jimmy W., additional

Published
2013
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