A computational study of the ternary mixtures of NaPF-EC and choline glycine ionic liquid.

This study investigates the structural and dynamic properties of ternary mixtures composed of NaPF, ethylene carbonate (EC), and the ionic liquid choline glycine (ChGly), with a focus on their potential as electrolytes for supercapacitors. The combination of NaPF-EC, known for its high ionic conductivity, with the biodegradable and environmentally friendly ChGly offers a promising approach to enhancing electrolyte performance. Through molecular simulations, we analyze how the inclusion of small concentrations of ChGly affects key properties such as density, cohesive energy, and ion mobility.

Electric double layer formation and storing energy processes on graphene-based supercapacitors from electrical and thermodynamic perspectives.

Atomistic molecular dynamics simulations were used to investigate the processes of electrical double layer formation and electrolyte confinement in graphene-based supercapacitors. For both processes, free energy calculations were used to analyze the thermodynamics involved in the electrolyte confinement and its re-arrangement in a double layer on the electrode surface. The value of the free energy of the formation of the double electric layer was related to the energy required to charge the supercapacitor, i.

Investigating the asymmetry in the EDL response of C/graphene supercapacitors.

Development of efficient electrodes is one of the main ways to increase the performance of an electrochemical energy storage device. It is known that such performance is associated with the electrode specific area, which allows a much larger interfacial interaction with the electrolyte. In this work, molecular dynamics is employed to model C60/graphene composite electrodes that can expand the effective area by approximately 70% relative to a pure graphene electrode.

Storing Energy in Biodegradable Electrochemical Supercapacitors.

The development of green and biodegradable electrical components is one of the main fronts of research to overcome the growing ecological problem related to the issue of electronic waste. At the same time, such devices are highly desirable in biomedical applications such as integrated bioelectronics, for which biocompatibility is also required. Supercapacitors for storage of electrochemical energy, designed only with biodegradable organic matter would contemplate both aspects, that is, they would be ecologically harmless after their service lifetime and would be an important component for applications in biomedical engineering.

GIAO-DFT-NMR characterization of fullerene-cucurbituril complex: the effects of the C@CB[9] host-guest mutual interactions.

Magnetic shielding constants for an isolated fullerene C, cucurbituril CB[9], and the host-guest complex C@CB[9] were calculated as a function of separation of the monomers. Our results in the gas phase and water indicate a significant variation of the magnetic properties for all atoms of the monomers in the complex and after liberation of fullerene C from the interior of the CB[9] cavity. The interaction between the two monomers results in a charge transfer that collaborates with a redistribution of electron density to deshield the monomers.

Imidazolium Ionic Liquid Mediates Black Phosphorus Exfoliation while Preventing Phosphorene Decomposition.

Forthcoming applications in electronics and optoelectronics make phosphorene a subject of vigorous research efforts. Solvent-assisted exfoliation of phosphorene promises affordable delivery in industrial quantities for future applications. We demonstrate, using equilibrium, steered and umbrella sampling molecular dynamics, that the 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF] ionic liquid is an excellent solvent for phosphorene exfoliation.

Atomically precise understanding of nanofluids: nanodiamonds and carbon nanotubes in ionic liquids.

A nanofluid (NF) is composed of a base liquid and suspended nanoparticles (NPs). High-performance NFs exhibit significantly better heat conductivities, as compared to their base liquids. In the present work, we applied all-atom molecular dynamics (MD) simulations to characterize diffusive and ballistic energy transfer mechanisms within nanodiamonds (NDs), carbon nanotubes (CNTs), and N-butylpyridinium tetrafluoroborate ionic liquid (IL).

Protein remains stable at unusually high temperatures when solvated in aqueous mixtures of amino acid based ionic liquids.

Using molecular dynamics simulations, we investigated the thermal stability and real-time denaturation of a model mini-protein in four solvents: (1) water, (2) 1-ethyl-3-methylimidazolium alaninate [EMIM][ALA] (5 mol% in water), (3) methioninate [EMIM][MET] (5 mol% in water), and (4) tryptophanate [EMIM][TRP] (5 mol% in water). Upon analyzing the radius of gyration, the solvent-accessible surface area, root-mean-squared deviations, and inter- and intramolecular hydrogen bonds, we found that the mini-protein remains stable at 30-40 K higher temperatures in aqueous amino acid based ionic liquids (AAILs) than in water. This thermal stability was correlated with the thermodynamics and shear viscosity of the AAIL-containing mixtures.

Free energy of solvation of carbon nanotubes in pyridinium-based ionic liquids.

Numerous prospective applications require the availability of individual carbon nanotubes (CNTs). Pristine CNTs, strongly hydrophobic in nature, are known to be either totally insoluble or poorly dispersible. While it is unlikely to be possible to prepare a real solution of CNTs in any solvent, the ability of certain solvents to maintain dispersions of CNTs for macroscopic times constitutes great research interest.

Polypeptide A9K at nanoscale carbon: a simulation study.

The amphiphilic nature of surfactant-like peptides is responsible for their propensity to aggregate at the nanoscale. These peptides can be readily used for a non-covalent functionalization of nanoparticles and macromolecules. This work reports an observation of supramolecular ensembles consisting of ultrashort carbon nanotubes (USCNTs), graphene (GR) and A9K polypeptides formed by lysine and arginine.

Exploding Nitromethane in Silico, in Real Time.

Nitromethane (NM) is widely applied in chemical technology as a solvent for extraction, cleaning, and chemical synthesis. NM was considered safe for a long time, until a railroad tanker car exploded in 1958. We investigate the detonation kinetics and explosion reaction mechanisms in a variety of systems consisting of NM, molecular oxygen, and water vapor.

Mixtures of amino-acid based ionic liquids and water.

New ionic liquids (ILs) involving increasing numbers of organic and inorganic ions are continuously being reported. We recently developed a new force field; in the present work, we applied that force field to investigate the structural properties of a few novel imidazolium-based ILs in aqueous mixtures via molecular dynamics (MD) simulations. Using cluster analysis, radial distribution functions, and spatial distribution functions, we argue that organic ions (imidazolium, deprotonated alanine, deprotonated methionine, deprotonated tryptophan) are well dispersed in aqueous media, irrespective of the IL content.

The Band Gap of Graphene Is Efficiently Tuned by Monovalent Ions.

Small monovalent ions are able to polarize carbonaceous nanostructures significantly. We report a systematic investigation of how monovalent and divalent ions influence valence electronic structure of graphene. Pure density functional theory is employed to compute electronic energy levels.

Buckybomb: Reactive Molecular Dynamics Simulation.

Energetic materials, such as explosives, propellants, and pyrotechnics, are widely used in civilian and military applications. Nanoscale explosives represent a special group because of the high density of energetic covalent bonds. The reactive molecular dynamics (ReaxFF) study of nitrofullerene decomposition reported here provides a detailed chemical mechanism of explosion of a nanoscale carbon material.

Can inorganic salts tune electronic properties of graphene quantum dots?

Electronic properties of graphene quantum dots (GQDs) constitute a subject of intense scientific interest. Being smaller than 20 nm, GQDs contain confined excitons in all dimensions simultaneously. GQDs feature a non-zero band gap and luminescence on excitation.

Strong electronic polarization of the C60 fullerene by imidazolium-based ionic liquids: accurate insights from Born-Oppenheimer molecular dynamic simulations.

Fullerenes are known to be polarizable due to their strained carbon-carbon bonds and high surface curvature. The electronic polarization of fullerenes is steadily of practical importance because it leads to non-additive interactions and, therefore, to unexpected phenomena. For the first time, hybrid density functional theory (HDFT) powered Born-Oppenheimer molecular dynamics (BOMD) simulations have been conducted to observe electronic polarization and charge transfer phenomena in the C60 fullerene at finite temperature (350 K).

Ionic clusters vs shear viscosity in aqueous amino acid ionic liquids.

Aqueous solutions of amino acid ionic liquids (AAILs) are of high importance for applications in protein synthesis and solubilization, enzymatic reactions, templates for synthetic study, etc. This work employs molecular dynamics simulations using our own force field to investigate shear viscosity and cluster compositions of three 1-ethyl-3-methylimidazolium (emim) amino acid salts: [emim][ala], [emim][met], and [emim][trp] solutions (2, 5, 10, 20, and 30 mol %) in water at 310 K. We, for the first time, establish simple correlations between cluster composition, on one side, and viscosity, on another side.

Atomistic description of fullerene-based membranes.

We present extensive atomistic molecular dynamics simulations of the structure and stability of fullerene-based membranes. The simulations provide a molecular description of the PhK (pentaaryl[60]fullerene anions, C60Ar5(-)·K(+)) and C8K (C60Ar5(-)·K(+) with octyl substituents) membranes. Physical chemical properties and molecular organization of PhK and C8K membranes elucidate various aspects related to their formation and potential applications.

Structure and supersaturation of highly concentrated solutions of buckyball in 1-butyl-3-methylimidazolium tetrafluoroborate.

Solubilization of fullerenes is of high interest because of their wide usage in both fundamental research and numerous applications. This paper reports molecular dynamics (MD) simulations of saturated and supersaturated solutions of C60 in 1-butyl-3-methylimidazolium tetrafluoroborate, [C4C1IM][BF4], room-temperature ionic liquid (RTIL). The simulations cover a wide range of temperatures between 280 and 500 K at ambient pressure.

Imidazolium Ionic Liquid Helps to Disperse Fullerenes in Water.

Light fullerenes attract significant interest in pharmacy and medicine as drug vectors and antioxidants and to block AIDS virus enzyme. The progress of these applications is hindered by poor solubility of fullerenes in aqueous media. We propose a highly efficient hydrophilic system to disperse the C60 fullerene based on the accurate atomistic-resolution computer simulations.

Solvent polarity considerations are unable to describe fullerene solvation behavior.

Atomistic molecular dynamics simulations were employed to investigate the solvation properties of the fullerene C60 in binary water/dimethyl sulfoxide (DMSO) mixtures. Structural analysis indicates a preferential solvation with the predominance of DMSO molecules in the first solvation shell for the solutions with low concentrations of DMSO. PMF calculations indicate a maximization of the hydrophobic interaction at low concentrations of DMSO.