Browsing by Author "Garg, Mohit"

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Addition of P3HT-grafted Silica nanoparticles improves bulk-heterojunction morphology in P3HT-PCBM blends, Scientific Reports
(Springer Nature, 2016-09) Garg, Mohit
We present molecular dynamics simulations of a ternary blend of P3HT, PCBM and P3HT-grafted silica nanoparticles (SiNP) for applications in polymer-based solar cells. Using coarse-grained models, we study the effect of SiNP on the spatial arrangement of PCBM in P3HT. Our results suggest that addition of SiNP not only alters the morphology of PCBM clusters but also improves the crystallinity of P3HT. We exploit the property of grafted SiNP to self-assemble into a variety of anisotropic structures and the tendency of PCBM to preferentially adhere to SiNP surface, due to favorable interactions, to achieve morphologies with desirable characteristics for the active layer, including domain size, crystallinity of P3HT, and elimination of isolated islands of PCBM. As the concentration of SiNP increases, the number of isolated PCBM molecules decreases, which in turn improves the crystallinity of P3HT domains. We also observe that by tuning the grafting parameters of SiNP, it is possible to achieve structures ranging from cylindrical to sheets to highly interconnected network of strings. The changes brought about by addition of SiNP shows a promising potential to improve the performance of these materials when used as active layers in organic photovoltaics.
Cellulose nanocrystal dispersions conjugated with symmetric and asymmetric dialkylamine groups
(Springer, 2024-06) Garg, Mohit
The present study discusses the effect of symmetric and asymmetric grafting on the surface of CNCs (cellulose nanocrystals) on their dispersion properties using dialkyl azetidinium salts. Three dialkylamine of different size and chain length were successfully grafted to the sulfate groups on the surface of CNCs by conjugation of azetidinium salts. The coupling process resulted in the formation of 2-hydroxypropyl-N-dialkylamine conjugated to the CNC sulfate groups abbreviated as C-N-C-Prop-2-OH-CNC, where m, n are the number of carbons in the alkyl groups, each with a total of , with . Molecular dynamics simulations were used to assess the probable morphology of the grafted chains and the interaction potential between CNCs. Steady shear simultaneously combined with polarized light imaging and oscillatory shear rheological measurements were used to evaluate for the first time the impact of the CNC surface modifications on their dispersion flow and optical properties. Overall, the results show that the different linker topologies could effectively promote different types of aggregation morphologies based on the size of the linker, their flexibility and their most probable conformation.
Comprehensive analysis of hydrazone Schiff bases: synthesis, structural characterization, DFT studies, molecular docking insights and bioactivity assessment
(Elsevier, 2025-07) Garg, Mohit
The four new hydrazone Schiff bases have been synthesized in absolute ethanol at the reflux of 78 °C. These hydrazones are named as: (E)-1-(2,4-dinitrophenyl)-2-(2-ethoxy benzylidene) hydrazine(2-EDNPH) (L1), (E)-1-(2,4-dinitrophenyl)-2-(4-ethoxy benzylidene) hydrazine(4-EDNPH) (L2), (E)-3-chloro-2-((2-(2,4-dinitrophenyl) hydrazinylidene) methyl) phenol(3-Cl-2-OH-DNPH) (L3) and (E)-1-(2,4-dinitrophenyl)-2-(thiophen-3-ylmethylene) hydrazine (3-Thiophene Carbaldehyde-DNPH) (L4). Spectroscopic and physicochemical techniques were employed to validate these compound's structure, including 1H NMR, 13C NMR spectra, UV–Vis, IR, and melting point. A solubility test is also carried out on all the Schiff bases, indicating that all four ligands are soluble in THF and DMF. The thermal breakdown behavior of all ligands is being examined by thermogravimetric analysis (TGA/DTG) at a heating rate of 10 °C min−1 under a nitrogen environment. The crystalline structure of L1 was also investigated in an XtaLAB AFC12 (RINC): Kappa single diffractometer, which included unit cell computation and data collecting. The radioactive photon was created with MoKα (λ = 0.7107Å). In addition, density functional theory (DFT) is utilized to compute the optimized molecular structures, stability, reactivity, and numerous chemical characteristics of the synthesized ligands. The in-silico prediction of ADME features revealed that synthesized compounds gain notable drug-like characteristics. Also, molecular docking was enforced to predict the inhibitory action of the β-ketoacyl acyl carrier (KAS1) protein of E. Coli (PDB Id: 6TZF) on the examined hydrazones. Finally, all ligands were to assess the anti-bacterial properties against gram-positive (B. subtilis and MRSA) and gram-negative (P. mirabilis and E. coli) infections; only L1 and L2 showed activity against these pathogens.
Computational design of isomeric naphthalenediimide–naphthodithiophene (NDI–NDT) copolymers for organic electronics
(ACS, 2025-09) Garg, Mohit; Ghosh, Sarbani
This study presents a comprehensive investigation of conjugated donor–acceptor (D–A) copolymers based on naphthalenediimide (NDI) and two structural isomers of naphthodithiophene (NDT), i.e., linear (L-NDT) and angular (A-NDT), designated as NDI–L-NDT and NDI–A-NDT, respectively. By systematically analyzing their molecular structure, (opto)electronic properties, photovoltaic performance, morphological analysis, and mechanical stability, this study reveals the profound influence of donor isomerism on material properties, relevant to organic electronic applications. In particular, NDI–L-NDT exhibits a lower bandgap attributed to its extended donor π-conjugation and nearly coplanar D–A conformation compared to NDI–A-NDT. NDI–A-NDT demonstrates superior photovoltaic performance due to its higher power conversion efficiency compared to its linear counterpart. Morphological studies based on molecular dynamics simulations reveal that films of both copolymers exhibit similar levels of crystallinity. However, NDI–L-NDT possesses greater thermal stability and mechanical flexibility, capable of withstanding up to 100% strain without cracking, attributed to its dynamic conformational adaptability, making it a promising candidate for flexible electronic applications. This work reveals the potential of structural isomerism in fine-tuning D–A copolymers for multifunctional roles, as donors, acceptors, or single-component materials in next-generation organic electronic devices.
Copper-mediated cyclization of thiosemicarbazones leading to 1,3,4-thiadiazoles: Structural elucidation, DFT calculations, in vitro biological evaluation and in silico evaluation studies
(Elsevier, 2024-05) Garg, Mohit
Cancer's global impact necessitates innovative and less toxic treatments. Thiosemicarbazones (TSCs), adaptable metal chelators, offer such potential. In this study, we have synthesized N (4)-substituted heterocyclic TSCs from syringaldehyde (TSL1, TSL2), and also report the unexpected copper-mediated cyclization of the TSCs to form thiadiazoles (TSL3, TSL4), expanding research avenues. This work includes extensive characterization and studies such as DNA/protein binding, molecular docking, and theoretical analyses to demonstrate the potential of the as-prepared TSCs and thiadiazoles against different cancer cells. The DFT results depict that the thiadiazoles exhibit greater structural stability and reduced reactivity compared to the corresponding TSCs. The docking results suggest superior EGFR inhibition for TSL3 with a binding constant value of − 6.99 Kcal/mol. According to molecular dynamics studies, the TSL3-EGFR complex exhibits a lower average RMSD (1.39 nm) as compared to the TSL1-EGFR complex (3.29 nm) suggesting that both the thiadiazole and thiosemicarbazone examined here can be good inhibitors of EGFR protein, also that TSL3 can inhibit EGFR better than TSL1. ADME analysis indicates drug-likeness and oral availability of the thiadiazole-based drugs. The DNA binding experiment through absorption and emission spectroscopy discovered that TSL3 is more active towards DNA which is quantitatively calculated with a Kb value of 4.74 × 106 M−1, Kq value of 4.04 × 104 M−1and Kapp value of 5 × 106 M−1. Furthermore, the BSA binding studies carried out with fluorescence spectroscopy showed that TSL3 shows better binding capacity (1.64 × 105 M−1) with BSA protein. All the compounds show significant cytotoxicity against A459-lung, MCF-7-breast, and HepG2-liver cancer cell lines; TSL3 exhibits the best cytotoxicity, albeit less effective than cisplatin. Thiadiazoles demonstrate greater cytotoxicity than the TSCs. Overall, the promise of TSCs and thiadiazoles in cancer research is highlighted by this study. Furthermore, it unveils unexpected copper-mediated cyclization of the TSCs to thiadiazoles.
Design & engineering of wood-inspired super-insulating foams
(APS, 2023) Garg, Mohit
Buildings account for 40% of the total U.S. energy consumption. The energy lost through building's walls, roofs and windows is the largest single waste of energy in most buildings. One way to contribute to the building energy efficiency consists in improving their thermal insulation by e.g., developing green and advanced functional materials as insulating panels. With the advent of the Green Economy, the use and valorization of lignocellulosic biomass as a possible alternative of fossil resources is a promising approach for elaborating low cost and high value-added insulation materials. Proper deconstruction or fractionation of cell wall components has indeed been reported to facilitate the development of a wide range of high value materials. The extraction of high aspect ratio cellulose nanomaterials (CNMs) or nanocelluloses, from e.g., wood cell walls, is especially creating a revolution in biobased materials for diverse applications such as packaging, cosmetics, automotive and electronics, owing to their low density, large surface area, and high strength-to-weight ratio. I will present our latest research on heat transport of fully bio-based foams and their thermal response as a function of relative humidity. The deconstruction of wood cell wall into cellulose nanofibers (CNFs) lays the foundation for the production of high-performance bio-based foams. I will discuss two engineering approaches to manufacture super-insulating foams: 1- the influence of chemical surface modification of CNFs on heat transfer of subsequent foams, and 2- the nature-inspired assembly of unmodified CNFs with another wood-biopolymer namely lignin, for enhanced performance. This presentation aims to share an insight on the potential of wood-based foams as thermal insulation materials, but also to inspire scientists, researchers, and future generations to exploit the biomass beyond traditional end-use products, such as for the engineering and manufacturing of sustainable advanced functional materials for energy transfer, storage, or conversion.
Electrocoagulation Influencing Parameters Investigation on Reactive Dyes in Textile Wastewater
(CRC Press, 2021) Garg, Mohit
Textile industry discharges lot of waste into the water body in terms of high color, dissolved organic and inorganic salt which causes serious concern to the environment. The present chapter reports experimental study on electrocoagulation (EC) process to remove color and chemical oxygen demand (COD) from a real textile waste water obtained from dyeing cotton fiber industries consisting reactive dye. A batch of experimental studies have been performed and effect of various operating parameters such as, contact time (t: 0–150 min), initial pH (pH0: 4–10), current density (j: 20–80 mA/cm2) and electrode spacing (z: 0.5–1.5 cm) on color and COD removal efficiency have been studied. The results indicate that pH of the solution significantly influences the removal efficiency in terms of COD and does not have significant effect on color removal efficiency. High current density and minimum distance between two electrodes favors the process. The scum and sludge are produced during color removal. The treatment of waste water for removal of color and COD together with proposed cost-effective method is useful for many industrial applications.
Evolution of electronic structure and optical properties of naphthalenediimide dithienylvinylene (NDI-TVT) polymer as a function of reduction level: a density functional theory study
(RSC, 2025) Garg, Mohit; Garg, Sarbani
Naphthalenediimide (NDI)-based donor–acceptor co-polymers with tunable electronic, optical, mechanical, and transport properties have shown immense potential as n-type conducting polymers in organic (opto)electronics. During the operation, the polymers undergo reduction at different charged states, which alters their (opto)electronic properties mainly due to the formation of the quasiparticles, polaron/bipolaron. The theoretical study based on quantum mechanical calculations can provide us with a detailed understanding of their (opto)electronic properties, which is missing to a great extent. To date, a theoretical understanding of how these properties vary with reduction levels for NDI-based polymers is completely missing. Herein, the evolution of the electronic structure and optical properties of the naphthalenediimide dithienylvinylene (NDI-TVT) polymer with varying reduction levels (Cred) is studied using density functional theory and time-dependent density functional theory, respectively, in the gaseous phase and solvent phase. We have envisaged that at lower reduction levels, Cred ≤ 100% (i.e., up to one negative charge per NDI moiety), only radical anions, i.e., polarons, are formed. The bipolarons are observed to be formed only at higher reduction levels, Cred > 100%. We note the coexistence of polarons and bipolarons for the intermediate reduction levels (100% < Cred < 200%). Finally, at 200% reduction levels, the presence of two electrons per NDI unit leads to the completely spin-resolved bipolaronic state formation, where one bipolaron is localized at every NDI unit. This aforementioned evolution of polarons and bipolarons with varying reduction levels is also prominently reflected in the calculated UV-vis-NIR absorption spectra. The detailed theoretical insights gained from the evolution of the (opto)electronic properties of NDI-TVT with reduction levels due to the formation of polaronic/bipolaronic states can guide the systematic design of n-type NDI-TVT-based (opto)electronic devices and in their advancement.
Exploration of aldazine Schiff bases as promising bioactive agents: a synergistic approach using DFT, ADME, antibacterial and cytotoxicity analysis
(Elsevier, 2026-01) Garg, Mohit
A straightforward method for synthesizing four new asymmetric Aldazine Schiff base derivatives using aromatic aldehydes and hydrazine precursors was successfully demonstrated under moderate conditions. These compound are designated as follows: 1-((E)-(((E)-2-ethoxy benzylidene) hydrazineylidene) methyl)naphthalene-2-ol (2-EHMN) (L1), 1-((4-ethoxy benzylidene) hydrazineylidene) methyl) naphthalene-2-ol (4-EHMN) (L2), 1-((2‑hydroxy-4-methoxybenzylidene) hydrazineylidene) methyl) naphthalene-2-ol (HMHMN) (L3), and 1-((2‑chloro-6-hydroxyybenzylidene) hydrazineylidene) methyl) naphthalene-2-ol (CHHMN) (L4). The compounds obtained were analyzed via FT-IR, 1H-/13CNMR spectroscopy, HRMS spectrometry techniques, and elemental analysis. Infrared (IR) spectroscopy, UV–Vis spectroscopy, and accurate melting point determination all contribute to the improved study of synthesised compounds. A comprehensive solubility analysis was conducted for all synthesized compounds, demonstrating their solubility in dichloromethane (DCM), tetrahydrofuran (THF), and dimethylformamide (DMF). Thermoanalytical studies of all the ligands were also examined and compared. Furthermore, a single-crystal X-ray diffraction (SCXRD) analysis of L1 was conducted using a single-crystal diffractometer, with unit cell calculations and data collection performed using MoKα radiation (λ = 0.7107 Å). Density functional theory (DFT) computations were used to optimise the structures of molecules and assess reactivity, durability, and electronic characteristics of the developed ligands. Molecular docking of L1, L2, and L3 has been done in different proteins, which gives precise results to show the activity for cytotoxicity and antibacterial studies. In silico, the ADME process calculations showed that the synthesised compounds have favourable drug-like features. In vitro antibacterial (L2 and L3) and cytotoxicity (L1) tests were also performed to assess their efficacy as therapeutic agents.
Exploring an N-Type Conducting Polymer (BBL) as a Potential Gas Sensing Material for NH3 and H2S Detection: A Theoretical Study
(2024) Hazra, Arnab; Garg, Mohit; Ghosh, Sarbani
Conducting polymers (CPs) have garnered significant interest in being used as an active material in gas sensors mainly because of their structural flexibility, ease of synthesis, and enhanced performance at room temperature. The p-type CPs and their composites are mostly studied in gas sensing, which, unfortunately, exhibit limitations in terms of selectivity, stability, and sensitivity toward reducing gases. This study focuses on one of the widely studied n-type polymers, BBL(benzimidazobenzophenanthroline), as an active material for the detection of two reducing gases, namely, ammonia (NH3)and hydrogen sulfide (H2S), theoretically. Through molecular dynamics (MD) simulation and density functional theory (DFT)approach, we understand the adsorption behavior and selectivity of NH3 and H2S in the BBL film. Our results show that BBL displays remarkable adsorption for ammonia gas compared to hydrogen sulfide gas without compromising the π − π stacked crystallites within the polymer film. The DFT calculations show the adsorption energy of -0.32 eV and -0.21 eV for NH3 and H2S, respectively. MD simulations show that adsorption takes place in the free voids within the thin films, helping the polymer films to maintain their crystallinity, which indicates, upon detection of reducing gases, the generated free electrons will be able to be smoothly transported through the π − π stack network. The detailed theoretical insights obtained from this study indicate the suitability of the n-type conducting polymer, BBL, for the detection of reducing gases.
Functionalized nitro-piperonal thiosemicarbazone based ruthenium(II)–arene complexes for DNA interaction, anticancer and flow cytometry studies
(RSC, 2025-06) Garg, Mohit
Functionalized thiosemicarbazones derived from 6-nitro piperonal and their corresponding Ru(II)–(η6-benzene) (RuBNPT, RuBNMT, RuBNCT and RuBNMeT)/(η6-p-cymene) (RuPNPT, RuPNMT, RuPNCT and RuPNMeT) complexes were synthesized and explored for their biological efficacy and anticancer potential. The impact on the complexes’ electronic characteristics, coordination affinity, and bioactivity of the piperonal substitution at the N(4)-position with morpholine (6NMT), pyrrolidine (6NPT), cyclohexyl (6NCT), and N-methyl (6NMeT) groups were investigated. Comprehensive characterization using UV-vis, FT-IR, NMR (1H and 13C), HRMS, and XRD (6NPT and RuPNMT) confirmed the structural integrity of the synthesized compounds. Density functional theory (DFT) calculations revealed insights into electronic and physicochemical properties, while molecular docking studies demonstrated effective binding with the EGFR, suggesting their potential as anticancer agents. DNA and BSA binding studies indicated intercalative and hydrophobic interactions, with RuPNMT exhibiting moderate binding affinity. Cytotoxicity assays, including MTT assay results, indicated the strong activity of the RuPNMT and RuPNPT compounds (RuPNMT and RuPNPT exhibited IC50 values of 10.5 μM and 27.2 μM, respectively, in MDA-MB-231 cells, and 24.6 μM and 58.1 μM in MCF-7 cells). Additionally, apoptosis studies were conducted on these compounds using AO–EB staining and flow cytometry. The presence of heteroatoms and planarity of the N(4)-substituent enhanced the bioactivity of the ligands, while coordination with Ru(II)–arene precursors further amplified their effectiveness. This study underscores the effectiveness of these complexes as promising agents for targeted cancer treatment.
Humidity-Dependent Thermal Boundary Conductance Controls Heat Transport of Super-Insulating Nanofibrillar Foams
(Elsevier, 2021-01) Garg, Mohit
Cellulose nanomaterial (CNM)-based foams and aerogels with thermal conductivities substantially below the value for air attract significant interest as super-insulating materials in energy-efficient green buildings. However, the moisture dependence of the thermal conductivity of hygroscopic CNM-based materials is poorly understood, and the importance of phonon scattering in nanofibrillar foams remains unexplored. Here, we show that the thermal conductivity perpendicular to the aligned nanofibrils in super-insulating ice-templated nanocellulose foams is lower for thinner fibrils and depends strongly on relative humidity (RH), with the lowest thermal conductivity (14 mW m−1 K−1) attained at 35% RH. Molecular simulations show that the thermal boundary conductance is reduced by the moisture-uptake-controlled increase of the fibril-fibril separation distance and increased by the replacement of air with water in the foam walls. Controlling the heat transport of hygroscopic super-insulating nanofibrillar foams by moisture uptake and release is of potential interest in packaging and building applications.
Illuminating anticancer pathways with pyrene Schiff bases: bridging simulations and experiments
(Elsevier, 2026-04) Garg, Mohit
Cytochrome P450 1A1 (CYP1A1) plays a key role in the metabolic activation of carcinogens, making its inhibition a promising chemopreventive strategy. In this study, three pyrene-1-carboxaldehyde-derived Schiff bases, PEBD, APSB, and PyAP were investigated as potential CYP1A1 inhibitors using an integrated computational and experimental approach. Density functional theory (DFT) calculations, molecular docking, molecular dynamics (MD) simulations, and ADME analyses were performed to elucidate their structural features, binding interactions, and drug-likeness. The compounds exhibited strong binding affinities toward CYP1A1, with PEBD showing the highest docking score (–13.89 kcal/mol) and MD binding energy (–41.13 ± 4.07 kcal/mol). Ethidium bromide displacement assays confirmed efficient intercalation into CT-DNA (Kb = 1.54 × 10⁴ M⁻¹ for PEBD). MTT assays revealed that PEBD exerted the strongest cytotoxicity toward breast cancer cell lines MCF-7 (IC₅₀ = 23.9 μM) and MDA-MB-231 (IC₅₀ = 36.7 μM), while remaining non-toxic to normal MCF-10A cells. Overall, these findings highlight PEBD as a promising polycyclic aromatic Schiff base scaffold for the development of CYP1A1-targeted chemopreventive agents against breast cancer.
Improving morphology of P3HT:PCBM bulk heterojunction solar cells with anisotropic shaped silica nanoparticles
(Elsevier, 2023) Ghosh, Sarbani; Garg, Mohit
Using coarse-grained molecular dynamics simulations we study blends of Poly(3-hexylthiophene-2,5-diyl) (P3HT), [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) and Silica nanoparticle (SiNP) to understand the effect of adding SiNP on morphology of P3HT:PCBM in Bulk heterojunction (BHJ) solar cells. We use an approximately 3 nm anisotropic shaped SiNP and predicted the morphology of BHJ upon its incorporation. The SiNP arrange themselves into anisotropic structures depending on the concentration of P3HT, PCBM and SiNP respectively creating a network like morphology. PCBM molecules utilize the surface energy of SiNP and gather at its surface forming a morphology which is beneficial for device efficiency. Our results suggest that an optimum weight fraction of all the three components leads to higher surface area of contact, optimum domain size and high percolation of domains throughout the system. The effective control of all the morphological parameters help in improving the charge generation, extraction and transport to electrodes, thereby improving the performance of BHJ solar cells.
In silico anti-viral assessment of phytoconstituents in a traditional (Siddha Medicine) polyherbal formulation – Targeting Mpro and pan-coronavirus post-fusion Spike protein
(Elsevier, 2023-07) Murugesan, Sankaranarayanan; Deepa, P. R.; Garg, Mohit
Novel nature of the viral pathogen SARS-CoV-2 and the absence of standard drugs for treatment, have been a major challenge to combat this deadly infection. Natural products offer safe and effective remedy, for which traditional ethnic medicine can provide leads. An indigenous poly-herbal formulation, Kabasura Kudineer from Siddha system of medicine was evaluated here using a combination of computational approaches, to identify potential inhibitors against two anti-SARS-CoV-2 targets – post-fusion Spike protein (structural protein) and main protease (Mpro, non-structural protein).
In silico evaluation of bisphosphonates identifies leading candidates for SARS-CoV-2 RdRp inhibition
(Elsevier, 2025-05) Garg, Mohit; Murugesan, Sankaranarayanan
The novel coronavirus disease (COVID-19) pandemic has resulted in 777 million confirmed cases and over 7 million deaths worldwide, with insufficient treatment options. Innumerable efforts are being made around the world for faster identification of therapeutic agents to treat the deadly disease. Post Acute Sequelae of SARS-CoV-2 infection or COVID-19 (PASC), also called Long COVID, is still being understood and lacks treatment options as well. A growing list of drugs are being suggested by various in silico, in vitro and ex vivo models, however currently only two treatment options are widely used: the RNA-dependent RNA polymerase (RdRp) inhibitor remdesivir, and the main protease inhibitor nirmatrelvir in combination with ritonavir. Computational drug development tools and in silico studies involving molecular docking, molecular dynamics, entropy calculations and pharmacokinetics can be useful to identify new targets to treat COVID-19 and PASC, as shown in this work and our recent paper that identified alendronate as a promising candidate. In this study, we have investigated all bisphosphonates (BPs) on the ChEMBL database which can bind competitively to nidovirus RdRp-associated nucleotidyl (NiRAN) transferase domain, and systematically down selected seven candidates (CHEMBL608526, CHEMBL196676, CHEMBL164344, CHEMBL4291724, CHEMBL4569308, CHEMBL387132, CHEMBL98211), two of which closely resemble the approved drugs minodronate and zoledronate. This work and our recent paper together provide an in silico mechanistic explanation for alendronate and zoledronate users having dramatically reduced odds of SARS-CoV-2 testing, COVID-19 diagnosis, and COVID-19-related hospitalizations, and indicate that similar observational studies in Japan with minodronate could be valuable.
Ion Diffusion through Nanocellulose Membranes: Molecular Dynamics Study
(ACS, 2021-12) Garg, Mohit
One of the most promising applications of nanocellulose is for membranes for energy storage devices including supercapacitors, batteries, and fuel cells. Several recent studies reported the fabrication of cellulose-based membranes where ionic conductivity was confined to channels. So far, theoretical understanding of the effect of the nanoconfinement and surface charged groups on the diffusion coefficient of ions in cellulose nanochannels is missing. In the present study, we perform atomistic molecular dynamics simulations to provide this theoretical understanding and unravel mechanisms affecting the ionic diffusion in nanochannels. We demonstrate that the diffusion coefficient of ions in cellulose nanochannels is reduced in comparison to its bulk value. The change of the diffusion coefficient depends on the density of charged surface groups in nanochannels and the channel height, and it is primarily caused by the Coulomb interaction between the ions and the surface. We believe that our results reveal an important structure/property relationship in cellulose nanochannels, and they show that accounting for the dependence of the diffusion coefficient on the charge of the surface groups and channel height can be important for the Nernst–Plank–Poisson modeling of the ion conductivity in nanomembranes as well as for accurate fitting the experimental data to extract the material parameters.
Magnesium oxide nanoparticles-cellulose acetate based composite beads for lead uptake from contaminated stream: Experimental and DFT based study
(Elsevier, 2026-02) Garg, Mohit; Chatterjee, Somak
Groundwater, a primary source of drinking water, is becoming increasingly contaminated with toxic heavy metals, particularly lead. The unregulated discharge of industrial effluents into water bodies further exacerbates the problem. Accordingly, an effective system is required to treat these pollutants. Although there are existing solutions with certain challenges, this study aims to develop efficient composite polymeric beads composed of cellulose acetate and magnesium oxide nanoparticles for effective removal of lead from contaminated water. Prepared beads were spherical, synthesized by the phase inversion of polymer solution with the help of a needle-syringe assembly. As-prepared beads were characterized based on its morphological and chemical characteristics, revealing porous texture with considerable crystallinity. Presence of Pbsingle bondO bond in FTIR spectra post lead adsorption highlighted synergy between lead ions and Mgsingle bondOH groups. Uptake mechanism involved the substitution of hydrogen ions by lead ions, resulting in the formation of stable Mgsingle bondOsingle bondPb complexes. This was facilitated by lead's lower electronegativity in contaminated water. Lead uptake by composite beads was governed by monolayer adsorption as evident from isotherm studies. A maximum uptake capacity of 500 mg/g was observed at 298 K, which increased to 600 mg/g at 318 K. Optimum dosage of 1 g/l was identified as ideal for achieving equilibrium conditions. Thermodynamic parameters confirmed that the adsorption process was spontaneous and endothermic in nature. Regeneration studies showed effective reusability up to two cycles, after which the removal capacity reached saturation. Isoelectric point was obtained at a pH value of 9.7. Presence of MgO helped in stabilising lead ions and prevented precipitate formation in alkaline medium, providing a minor reduction in lead removal, as compared to conventional adsorbents. Furthermore, Density functional theory (DFT) based simulation was performed suggesting collective indication of consistent trends, with both approaches converging towards the same adsorption behaviour and Pbsingle bondO interaction patterns.
Microscopic Insights of Electrochemical Switching of Poly(benzimidazobenzophenanthroline) (BBL) Thin Film: A Molecular Dynamics Study
(ACS, 2009-04) Sarbani, Ghosh; Garg, Mohit
Carbon nanotubes typically require the use of a dispersing or stabilizing agent to prevent significant aggregation during incorporation into a polymer matrix. These additives must be strongly associated, either covalently or physically, to achieve their purpose. In this study, multi-walled carbon nanotubes (MWNTs) were dispersed into an epoxy matrix using polyethylenimine (PEI) as a dispersant that was either covalently attached to the nanotubes or physically mixed to result in only noncovalent interaction. Epoxy composites containing covalently modified MWNTs exhibited greater storage modulus and reduced electrical conductivity.
Moisture uptake in nanocellulose: the effects of relative humidity, temperature and degree of crystallinity
(Institute for Metals Superplasticity Problems, 2021-08) Garg, Mohit; Ghosh, Sarbani
Hydrogen has the potential to be an alternative source of energy. However, most of the research on hydrogen storage carried out in the past is based on low temperature (<80 K) whereas storage near room temperature is desired. Here, we report room-temperature hydrogen storage capacity of defective single-walled carbon nanotubes (SWCNT) investigated using molecular dynamics simulations and density functional theory. Four different types of defective SWCNTs are considered to study room temperature hydrogen storage. We observed maximum adsorption capacity of SWCNT with 5 and 8-membered ring defects, namely, D1. The SWCNT with other three defects studied here, Stone-Wales with 5- and 7-membered ring defect (D2), 5-membered ring defect (D3), and 3-, 5- and 8-membered ring defect (D4) have negative adsorption effect compared to the defect-free SWCNT. The highest gravimetric capacity of 1.82 wt.% is found for the D1 defective SWCNT at room temperature, 298 K and 140 atm. The DFT calculations show that hydrogen adsorption strongly depends on the type of defect where the 8-membered ring has the highest adsorption energy and the 3-membered ring has the lowest adsorption energy. A combination of 5- and 8-membered defective rings can increase hydrogen adsorption significantly even at room temperature.