Publications by authors named "Anurag Prakash Sunda"

Binary ionic melts formed by a protic ionic liquid (PIL) 1,2,4-triazolium methanesulfonate ([TAZ][MS]) dissolved in methanesulfonic acid are studied as non-stoichiometric electrolytes. The composition-driven structure-property relationship of methanesulfonic acid is explored at varying molar fraction ratios from 0/100 to 10/90, 20/80, and 30/70 by the addition of 1,2,4-triazolium methanesulfonate [TAZ][MS] IL. To unveil molecular characteristics of these mixtures of [TAZ][MS] PIL and CHSOH, we performed classical molecular dynamics simulations at varying temperatures from 293 to 303, 363, and 423 K.

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Alkaline fuel cells rely on the movement of hydroxide anions (OH) for their operation, yet these anions face challenges in efficient conduction due to their limited diffusion coefficient and substantial mass compared to proton (H) transport. Within the covalent organic framework structure, ordered channels offer a promising solution for the OH ion transport. Herein, we synthesized a cationic covalent organic framework (vTAPA) via the solvothermal-assisted Zincke reaction.

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Aβ1-40 peptide and Aβ1-42 peptide are the building units of beta-amyloid plaques present in Alzheimer's disease (AD)-affected brain. The binding affinity of various divalent metal ions such as Cu and Zn present in AD-affected brain with different amino acids available in Aβ-peptide became the focus to explore their role in soluble neurotoxic oligomer formation. Cu metal ions are known to enhance the neurotoxicity of the Aβ1-42 peptide by catalyzing the formation of soluble neurotoxic oligomers.

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We present a classical molecular dynamics simulations study on the nanostructures of the sulfonated polybenzophenone (SPK) block copolymer membranes at 300 K and 353 K. The results of the radial distribution function (RDF) show that the interactions of the sulfonate groups of the membrane with the hydronium ions are more significant than those of water due to the strong electrostatic attraction over the hydrogen bonding. However, the effect of temperatures on the RDF profile seems insignificant.

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This report describes the synthesis of a new class of secondary interaction (SeCHCl)-controlled molecular rotor having a Cl-Pd-Cl rotor spoke attached onto a Se-Pd-Se axle. NMR data acquired at various temperatures established ΔG/ΔG values of 15.5 and 17.

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The variation of the center atom in the cation from an N to a P-atom leads to improved physiochemical properties of protic ionic liquids (PILs) which are suitable for electrolyte applications. We present an atomistic simulations study to compare the effect of an alkyl or aryl group on trioctylammonium triflate ([HN(Oct)3][TFO]) and triphenylammonium triflate ([HN(Ph)3][TFO]) with their phosphonium analogues. We have computed the binding energy from quantum chemical calculations and physical properties such as the viscosity and the electrical conductivity of PILs from molecular dynamics simulations.

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A biologically important polypeptide [with an alternate sequence of alanine (ALA) and 2-aminobutyric acid (AiB)] is used as a linker molecule to investigate the charge-transfer phenomenon between CdSe nanoparticle (NP) (diameter ∼6-7 nm) assemblies and gold (Au) substrates. The (ALA-AiB)n polypeptides, with varying chain lengths n = 5, 8, 11, were attached to the surface to form self-assembled monolayers (SAMs) through a thiol group located either at the N-terminal or C-terminal of the sequence. Temperature dependent photoluminescence (PL) spectra showed anomalous behavior in the quenching regime of CdSe NPs in the 237 K to 290 K region.

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Critical aspects of thermal behavior and the electrolytic properties of solid-state Protic Organic Ionic Plastic Crystals (POIPCs) are unknown. We present molecular dynamics (MD) simulations on a perfect crystal and a vacancy model to probe such physical phenomena in POIPCs using 1,2,4-triazolium perfluorobutanesulfonate ([TAZ][pfBu]) as an example. The results show the existence of a rotator phase wherein the cations, although translationally ordered are disordered rotationally and exhibit a tumbling motion which significantly affects hydrogen bond lifetimes.

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Protic ionic liquids (PILs) are of great interest as electrolytes in various energy applications. Molecular dynamics simulations of trialkylammonium (with varying alkyl group such as methyl, ethyl, and n-propyl) triflate PILs are performed to characterize the influence of the alkyl group on the acidic site (N-H) of the ammonium cation. Spatial distribution function of anions over this site on the cation reveals significant influence of the length of alkyl tail on intermolecular structure.

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Ammonium-based benzyl-NX3 (X = methyl, ethyl) trifluoromethanesulfonate (TFA) ionic liquids (ILs) are low cost, nontoxic, thermally stable ion-conducting electrolytes in fuel cells and batteries. In the present study, we have characterized the structure and dynamics of these ILs using molecular dynamics (MD) simulations and ionic conductivity using electro-chemical impedance spectroscopy (EIS) at varying temperature and relative humidity (RH). Results from MD simulations predict that cation-cation and cation-anion interactions are stronger in benzyltrimethylammonium (BzTMA) compared to benzyltriethylammonium (BzTEA) that diminish with increase in RH.

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Triflic acid is a functional group of perflourosulfonated polymer electrolyte membranes where the sulfonate group is responsible for proton conduction. However, even at extremely low hydration, triflic acid exists as a triflate ion. In this work, we have developed a force-field for triflic acid and triflate ion by deriving force-field parameters using ab initio calculations and incorporated these parameters with the Optimized Potentials for Liquid Simulations - All Atom (OPLS-AA) force-field.

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