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Bakó I, Pusztai L, Pothoczki S. Topological descriptors and Laplace spectra in simple hydrogen bonded systems. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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2
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Ghanghas R, Vasudevan S. Geometries of hydrogen bonds in water-ethanol mixtures from ab initio molecular dynamics simulations. Phys Chem Chem Phys 2022; 24:23570-23577. [PMID: 36129380 DOI: 10.1039/d2cp01238c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We outline a simple procedure to determine the geometry of hydrogen bonds between different molecular species in binary mixtures from ab initio molecular dynamics (AIMD) trajectories. Here we determine the geometry of the hydrogen bonds arising from intermolecular OH⋯O interactions between different H-bonded pairs, water-water, ethanol-ethanol and water-ethanol in water-alcohol mixtures at different compositions by plotting the intermolecular non-bonded OH⋯O and O⋯O distances, and the ∠HO⋯O (θ) angles for each of the possible pairs in the ensemble. Two regions separate out in each of the scatter-plots; the one with short OH⋯O and O⋯O intermolecular distances and almost linear ∠HO⋯O angles may be identified as the region where the intermolecular OH⋯O geometry would be favorable for hydrogen bonding. Using the different geometric criteria for each of the three possible H-bonded pairs we estimate the average number of water and ethanol molecules that are hydrogen bonded to a water molecule, and to an ethanol molecule, respectively, at different mole fractions of the mixture. We validate the results from values of the chemical shift of the two OH resonances (water and ethanol) in the proton NMR spectra of the mixtures at different concentrations as these values are known to be sensitive to the local chemical environment of the resonating nuclei.
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Affiliation(s)
- Ritu Ghanghas
- Department of Inorganic and Physical Chemistry, IISc, Bangalore, India.
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3
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Wang X, Mori Y, Tsuchiya K. Periodicity in ultrasonic atomization involving beads-fountain oscillations and mist generation: Effects of driving frequency. ULTRASONICS SONOCHEMISTRY 2022; 86:105997. [PMID: 35417794 PMCID: PMC9018148 DOI: 10.1016/j.ultsonch.2022.105997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/14/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Ultrasonic atomization induced by high driving frequency, generally on the order of 1 MHz or higher, could involve a liquid fountain in the form of a corrugated jet, or a chain of "beads" of submillimeter diameter in contact. This study concerns dynamics/instability of such beads fountain, observed under lower input power density (≤ 6 W/cm2) of the "flat" ultrasound transducer with a "regulating" nozzle equipped, exhibiting time-varying characteristics with certain periodicity. High-speed, high-resolution images are processed for quantitative elucidation: frequency analysis (fast Fourier transform) and time-frequency analysis (discrete wavelet transform) are employed, respectively, to evaluate dominant frequencies of beads-surface oscillations and to reveal factor(s) triggering mist emergence. The resulting time variation in the measured (or apparent) fountain structure, associated with the recurring-beads size scalable to the ultrasound wavelength, subsumes periodic nature predictable from simple physical modeling as well as principle. It is further found that such dynamics in (time-series data for) the fountain structure at given height(s) along a series of beads would signal "bursting" of liquid droplets emanating out of a highly deformed bead often followed by a cloud of tiny droplets, or mist. In particular, the bursting appears to be not a completely random phenomenon but should concur with the fountain periodicity with a limited extent of probability.
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Affiliation(s)
- Xiaolu Wang
- Dept. of Chemical Engineering and Materials Science, Doshisha Univ., Kyotanabe, Kyoto 610-0321, Japan
| | - Yasushige Mori
- Dept. of Chemical Engineering and Materials Science, Doshisha Univ., Kyotanabe, Kyoto 610-0321, Japan
| | - Katsumi Tsuchiya
- Dept. of Chemical Engineering and Materials Science, Doshisha Univ., Kyotanabe, Kyoto 610-0321, Japan.
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4
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Perera A, Požar M, Lovrincevic B. Camel back shaped Kirkwood-Buff Integrals. J Chem Phys 2022; 156:124503. [DOI: 10.1063/5.0084520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Some binary mixtures, such as specific alcohol-alkane mixtures, or even water-tbutanol, exhibit two humps "camel back" shaped KBI. This is in sharp contrast with usual KBI of binary mixtures having a single extremum. This extremum is interpreted as the region of maximum concentration fluctuations, and usually occurs in binary mixtures presenting appreciable micro-segregation, and corresponds to where the mixture exhibit a percolation of the two species domains. In this paper, it is shown that two extrema occur in binary mixtures when one species forms "meta-particle" aggregates, the latter which act as a meta-species, and have their own concentration fluctuations, hence their own KBI extremum. This "meta-extremum" occurs at low concentration of the aggregate-forming species (such as alcohol in alkane), and is independant of the other usual extremum observed at mid volume fraction occupancy. These systems are a good illustration of the concept of the duality between concentration fluctuations and micro-segregation.
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Affiliation(s)
- Aurelien Perera
- Laboratoire de Physique Theorique de Matière Condensée, Sorbonne Université, France
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5
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Kitaoka H, Hashimoto K, Nishi N, Sakka T. Solid Surface Induced Anisotropic Clustering in Ethanol-Cyclohexane Binary Liquids Studied by Molecular Dynamics Simulations. CHEM LETT 2021. [DOI: 10.1246/cl.210292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Haru Kitaoka
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Kota Hashimoto
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Tetsuo Sakka
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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6
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Esipova NE, Itskov SV. Kinetics of Air Bubble Growth on a Silicon Substrate in Alcohol and Water–Alcohol Media. COLLOID JOURNAL 2021. [DOI: 10.1134/s1061933x21040037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Zueva OS, Makarova AO, Khairutdinov BI, Zuev YF, Turanov AN. Association of ionic surfactant in binary water—ethanol media as indicator of changes in structure and properties of solvent. Russ Chem Bull 2021. [DOI: 10.1007/s11172-021-3203-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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9
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Characterisation of single malt Scotch Whisky using low powered ultrasound and UV‐Visible spectroscopy. JOURNAL OF THE INSTITUTE OF BREWING 2020. [DOI: 10.1002/jib.633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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10
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Jukić I, PoŽar M, Lovrinčević B. Comparative analysis of ethanol dynamics in aqueous and non-aqueous solutions. Phys Chem Chem Phys 2020; 22:23856-23868. [PMID: 33073281 DOI: 10.1039/d0cp03160g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this study, we compare the results for vibrational, reorientational and hydrogen bond dynamics of ethanol in water and in hexane across the whole concentration range. Water and hexane are both commonly used as solvents, but so far, it has been unclear to what extent they modify the solute dynamics. Ethanol is chosen as the solute because it is an aliphatic molecule that is miscibile with both solvents. It is known that ethanol forms micelle-like domains in water and cyclic clusters resembling loops in hexane. This structural micro-heterogeneity is well known both in experiments and in simulations. The main question we raise here is: is there a signature of micro-heterogeneity in the dynamical quantities of ethanol? We focus on quantities such as the vibrational spectra, the reorientational correlation functions, the self-diffusion coefficients, the ethanol-ethanol hydrogen bond correlation functions and the corresponding hydrogen bond histograms. For the first time ever, we compute the van Hove functions to reveal the dynamical variations of spatial correlations in these systems. All these results complement each other and provide a unifying dynamical description of ethanol in binary mixtures.
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Affiliation(s)
- Ivo Jukić
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
| | - Martina PoŽar
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
| | - Bernarda Lovrinčević
- Department of Physics, Faculty of Science, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
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11
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Sinha S, Gharat PM, Pal H, Dutta Choudhury S. Lumichrome tautomerism in alcohol-water mixtures: Effect of carbon chain length and mole fraction of alcohols. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113621] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Ma Y, Yoshikawa Y, Oana H, Yoshikawa K. Marked Difference in the Conformational Transition of DNA Caused by Propanol Isomer. Polymers (Basel) 2020; 12:polym12071607. [PMID: 32707704 PMCID: PMC7407297 DOI: 10.3390/polym12071607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 11/16/2022] Open
Abstract
We measured the changes in the higher-order structure of DNA molecules (λ phage DNA, 48 kbp) at different concentrations of 1- and 2-propanol through single-molecular observation. It is known that 2-propanol is usually adapted for the procedure to isolate genomic DNA from living cells/organs in contrast to 1-propanol. In the present study, it was found that with an increasing concentration of 1-propanol, DNA exhibits reentrant conformational transitions from an elongated coil to a folded globule, and then to an unfolded state. On the other hand, with 2-propanol, DNA exhibits monotonous shrinkage into a compact state. Stretching experiments under direct current (DC) electrical potential revealed that single DNA molecules intermediately shrunk by 1- and 2-propanol exhibit intrachain phase segregation, i.e., coexistence of elongated and compact parts. The characteristic effect of 1-propanol causing the reentrant transition is argued in terms of the generation of water-rich nanoclusters.
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Affiliation(s)
- Yue Ma
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan; (Y.M.); (Y.Y.)
| | - Yuko Yoshikawa
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan; (Y.M.); (Y.Y.)
| | - Hidehiro Oana
- Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan;
| | - Kenichi Yoshikawa
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan; (Y.M.); (Y.Y.)
- Correspondence: ; Tel.: +81-774-65-6131
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13
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Lu X, Jiménez-Riobóo RJ, Leech D, Gutiérrez MC, Ferrer ML, Del Monte F. Aqueous-Eutectic-in-Salt Electrolytes for High-Energy-Density Supercapacitors with an Operational Temperature Window of 100 °C, from -35 to +65 °C. ACS APPLIED MATERIALS & INTERFACES 2020; 12:29181-29193. [PMID: 32484323 DOI: 10.1021/acsami.0c04011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water-in-salt (WIS) electrolytes are gaining increased interest as an alternative to conventional aqueous or organic ones. WIS electrolytes offer an interesting combination of safety, thanks to their aqueous character, and extended electrochemical stability window, thanks to the strong coordination between water molecules and ion salt. Nonetheless, cost, the tendency of salt precipitation, and sluggish ionic transfer leading to poor rate performance of devices are some intrinsic drawbacks of WIS electrolytes that yet need to be addressed for their technological implementation. It is worth noting that the absence of "free'' water molecules could also be achieved via the addition of a certain cosolvent capable of coordinating with water. This is the case of the eutectic mixture formed between DMSO and H2O with a molar ratio of 1:2 and a melting point as low as -140 °C. Interestingly, addition of salts at near-saturation conditions also resulted in an increase of the boiling point of the resulting solution. Herein, we used a eutectic mixture of DMSO and H2O for dissolution of LiTFSI in the 1.1-8.8 molality range. The resulting electrolyte (e.g., the so-called aqueous-eutectic-in-salt) exhibited excellent energy and power densities when operating in a supercapacitor cell over a wide range of extreme ambient temperatures, from as low as -35 °C to as high as +65 °C.
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Affiliation(s)
- Xuejun Lu
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientı́ficas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Rafael J Jiménez-Riobóo
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientı́ficas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Donal Leech
- School of Chemistry, National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland
| | - María C Gutiérrez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientı́ficas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - M Luisa Ferrer
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientı́ficas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Francisco Del Monte
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientı́ficas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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14
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Carrasco-Huertas G, Jiménez-Riobóo RJ, Gutiérrez MC, Ferrer ML, del Monte F. Carbon and carbon composites obtained using deep eutectic solvents and aqueous dilutions thereof. Chem Commun (Camb) 2020; 56:3592-3604. [DOI: 10.1039/d0cc00681e] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Extending the “all-in-one” features of DESs to DES/H2O binary mixtures.
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Affiliation(s)
- Gaspar Carrasco-Huertas
- Instituto de Ciencia de Materiales de Madrid (ICMM)
- Consejo Superior de Investigaciones Científicas (CSIC)
- Cantoblanco 28049
- Spain
| | - Rafael J. Jiménez-Riobóo
- Instituto de Ciencia de Materiales de Madrid (ICMM)
- Consejo Superior de Investigaciones Científicas (CSIC)
- Cantoblanco 28049
- Spain
| | - María Concepción Gutiérrez
- Instituto de Ciencia de Materiales de Madrid (ICMM)
- Consejo Superior de Investigaciones Científicas (CSIC)
- Cantoblanco 28049
- Spain
| | - María Luisa Ferrer
- Instituto de Ciencia de Materiales de Madrid (ICMM)
- Consejo Superior de Investigaciones Científicas (CSIC)
- Cantoblanco 28049
- Spain
| | - Francisco del Monte
- Instituto de Ciencia de Materiales de Madrid (ICMM)
- Consejo Superior de Investigaciones Científicas (CSIC)
- Cantoblanco 28049
- Spain
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15
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Adichtchev SV, Karpegina YA, Okotrub KA, Surovtseva MA, Zykova VA, Surovtsev NV. Brillouin spectroscopy of biorelevant fluids in relation to viscosity and solute concentration. Phys Rev E 2019; 99:062410. [PMID: 31330595 DOI: 10.1103/physreve.99.062410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 01/11/2023]
Abstract
The measurement of intracellular viscoelastic properties by Brillouin scattering is a rapidly developing field in biophysics and medicine. Here, the Brillouin spectroscopy is applied for a number of aqueous solutions of biorelevant molecules to reveal relations between the Brillouin line parameters (frequency and width) and viscosity or solute concentration. It is found that for the majority of the studied biorelevant molecules the solute concentration governs the Brillouin frequency in a universal manner. On the other hand, the relations between the macroscopic viscosity and Brillouin peak parameters are different for different solutes. We conclude that for biological fluids the viscosity evaluation from Brillouin data needs prior knowledge about the chemical composition. This result challenges the fidelity of the indirect experimental determinations of the cellular viscosity, when small molecule solutions are used for the calibration.
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Affiliation(s)
- S V Adichtchev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Yu A Karpegina
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - K A Okotrub
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - M A Surovtseva
- Research Institute of Clinical and Experimental Lymphology-Branch of Institute of Cytology and Genetics, Russian Academy of Sciences, 630060 Novosibirsk, Russia
| | - V A Zykova
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - N V Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
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16
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Lovrinčević B, Bella A, Le Tenoux-Rachidi I, Požar M, Sokolić F, Perera A. Methanol-ethanol “ideal” mixtures as a test ground for the computation of Kirkwood-Buff integrals. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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17
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van der Sman R. Scaling of Flory-Huggins interaction parameter for polyols with chain length and number of hydroxyl groups. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2019.05.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Hazra MK, Bagchi B. Non-linearity in dipolar solvation dynamics in water-ethanol mixture: Composition dependence of free energy landscape. J Chem Phys 2019; 151:084502. [DOI: 10.1063/1.5097751] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Milan K. Hazra
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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19
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Roldán-Ruiz M, Jiménez-Riobóo R, Gutiérrez M, Ferrer M, del Monte F. Brillouin and NMR spectroscopic studies of aqueous dilutions of malicine: Determining the dilution range for transition from a “water-in-DES” system to a “DES-in-water” one. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.03.133] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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20
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Molecular simulation of penetration separation for ethanol/water mixtures using two-dimensional nanoweb graphynes. Chin J Chem Eng 2019. [DOI: 10.1016/j.cjche.2018.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Posada E, Roldán-Ruiz M, Jiménez Riobóo R, Gutiérrez M, Ferrer M, del Monte F. Nanophase separation in aqueous dilutions of a ternary DES as revealed by Brillouin and NMR spectroscopy. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.11.139] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Basařová P, Pišlová J, Mills J, Orvalho S. Influence of molecular structure of alcohol-water mixtures on bubble behaviour and bubble surface mobility. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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23
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Baek S, Moon HS, Kim W, Jeon S, Yong K. Effect of liquid droplet surface tension on impact dynamics over hierarchical nanostructure surfaces. NANOSCALE 2018; 10:17842-17851. [PMID: 30221273 DOI: 10.1039/c8nr04539a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Analyzing impact dynamics is important for practical applications of superhydrophobic surfaces, because these nonwetting surfaces frequently encounter impacting liquid droplets in real environments. Thus, various studies have been conducted to investigate impact dynamics by examining the correlation between the behaviors of impacting liquid droplets and several determining parameters, such as impacting velocity, surface structure and surface energy. The impacting behaviors of pure water droplets were the main focus in most previous studies; the effect of surface tension, another critical parameter, on impact dynamics has rarely been investigated. In the current work, we have newly studied the effects of liquid surface tension on impact dynamics using an ethanol-water solution as a model liquid system. We systematically varied the liquid's surface tension between 72 and 32 mN m-1 by changing the ethanol concentration from 0 to 20 wt%. This range of composition drastically changed the surface tension while it did not significantly affect other physical properties, such as density and viscosity. For an impact dynamics study, two surfaces, namely ZnO nanowires (NWs) and ZnO/Si hierarchical (HIE) structures, were prepared. As the surface tension decreased, the static water contact angle (CA) decreased on both surfaces. Under dynamic conditions, our analysis using a high-speed camera and a quartz crystal microbalance (QCM) showed that lowering the surface tension causes the transition from the anti-wetting to wetting state. The transition We numbers were obtained on both surfaces for various surface tensions of liquids. Under the same dropping conditions of liquids, the ZnO/Si HIE surface shows higher transition We numbers than the ZnO NW surface, which is due to the higher fraction of air pockets in the hierarchical structure, originating from dual dimensional structures. To understand the mechanism of dynamic transition, we developed a model for ZnO/Si HIE structures based on three determining pressures: anti-wetting, wetting, and effective water hammer pressures. The modeling results explain the experimental observations. The results of our model system are highly useful for understanding the impact dynamic behaviors of various liquids on non-wetting surfaces.
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Affiliation(s)
- Seunghyeon Baek
- Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea.
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Millare JC, Basilia BA. Nanobubbles from Ethanol-Water Mixtures: Generation and Solute Effects via Solvent Replacement Method. ChemistrySelect 2018. [DOI: 10.1002/slct.201801504] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jeremiah C. Millare
- School of Chemical; Biological; Materials Engineering and Sciences; Mapua University; Muralla Street, Intramuros, Manila Philippines 1002
| | - Blessie A. Basilia
- School of Chemical; Biological; Materials Engineering and Sciences; Mapua University; Muralla Street, Intramuros, Manila Philippines 1002
- Materials Science Division; Industrial Technology Development Institute; Department of Science and Technology; General Santos Avenue, Bicutan, Taguig, Metro Manila Philippines 1631
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25
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Hazra MK, Bagchi B. Collective excitations and ultrafast dipolar solvation dynamics in water-ethanol binary mixture. J Chem Phys 2018; 148:114506. [DOI: 10.1063/1.5019405] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Milan K. Hazra
- SSCU, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- SSCU, Indian Institute of Science, Bangalore 560012, India
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26
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Mukherjee D, Ortiz Rodriguez LI, Hilaire MR, Troxler T, Gai F. 7-Cyanoindole fluorescence as a local hydration reporter: application to probe the microheterogeneity of nine water-organic binary mixtures. Phys Chem Chem Phys 2018; 20:2527-2535. [PMID: 29313858 DOI: 10.1039/c7cp07160d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Considerable efforts have been devoted to the development of spectroscopic probes that are sensitive to water and can be used to monitor, for example, biological and chemical processes involving dehydration or hydration. Continuing this line of research, herein we show that 7-cyanoindole can serve as a sensitive fluorescence probe of hydration as its fluorescence properties, including intensity, peak wavelength and lifetime, depend on the amount of water in nine water-organic solvent mixtures. Our results indicate that 7-cyanoindole is not only able to reveal the underlying microheterogeneity of these binary solvent systems, but also offers distinct advantages. These include: (1) its fluorescence intensity increases more than ten times upon going from a hydrated to a dehydrated environment; (2) its peak wavelength shifts as much as 35 nm upon dehydration; (3) its single-exponential fluorescence decay lifetime increases from 2.0 ns in water to 8-16 ns in water-organic binary mixtures, making it viable to distinguish between differently hydrated environments via fluorescence lifetime measurements; and (4) its absorption spectrum is significantly red-shifted from that of indole, making selective excitation of its fluorescence possible in the presence of naturally occurring amino-acid fluorophores. Moreover, we find that for seven binary mixtures the fluorescence lifetimes of 7-cyanoindole measured at solvent compositions where maximum microheterogeneity occurs correlate linearly with the peak wavenumbers of its fluorescence spectra obtained in the respective pure organic solvents. This suggests that the microheterogeneities of these binary mixtures bear certain similarity, a phenomenon that warrants further investigation.
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Affiliation(s)
- Debopreeti Mukherjee
- Department of Chemistry University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
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Požar M, Perera A. Evolution of the micro-structure of aqueous alcohol mixtures with cooling: A computer simulation study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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DiGuiseppi D, Milorey B, Lewis G, Kubatova N, Farrell S, Schwalbe H, Schweitzer-Stenner R. Probing the Conformation-Dependent Preferential Binding of Ethanol to Cationic Glycylalanylglycine in Water/Ethanol by Vibrational and NMR Spectroscopy. J Phys Chem B 2017; 121:5744-5758. [DOI: 10.1021/acs.jpcb.7b02899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Nina Kubatova
- Institut
für Organische Chemie und Chemische Biologie, Johann Wolfgang Goethe-Universität, 60438 Frankfurt am Main, Germany
| | | | - Harald Schwalbe
- Institut
für Organische Chemie und Chemische Biologie, Johann Wolfgang Goethe-Universität, 60438 Frankfurt am Main, Germany
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29
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On the micro-heterogeneous structure of neat and aqueous propylamine mixtures: A computer simulation study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Požar M, Perera A. Lifshitz phase: the microscopic structure of aqueous and ethanol mixtures of 1,n-diols. Phys Chem Chem Phys 2017; 19:14992-15004. [DOI: 10.1039/c7cp01949a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We study binary mixtures of ethylene glycol and 1,3-propandiol with water or ethanol using computer simulations.
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Affiliation(s)
- Martina Požar
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600)
- Université Pierre et Marie Curie
- Paris cedex 05
- France
- Department of Physics
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600)
- Université Pierre et Marie Curie
- Paris cedex 05
- France
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31
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Posada E, López-Salas N, Jiménez Riobóo RJ, Ferrer ML, Gutiérrez MC, del Monte F. Reline aqueous solutions behaving as liquid mixtures of H-bonded co-solvents: microphase segregation and formation of co-continuous structures as indicated by Brillouin and 1H NMR spectroscopies. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp02180a] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Deep eutectic solvents (DESs) offer a suitable alternative to conventional solvents in terms of both performance and cost-effectiveness.
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Affiliation(s)
- E. Posada
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
| | - N. López-Salas
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
| | - R. J. Jiménez Riobóo
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
| | - M. L. Ferrer
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
| | - M. C. Gutiérrez
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
| | - F. del Monte
- Instituto de Ciencia de Materiales de Madrid-ICMM
- Consejo Superior de Investigaciones Científicas-CSIC
- 28049-Madrid
- Spain
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32
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Chand A, Chowdhuri S. Behaviour of aqueous N-methylacetamide solution in presence of ethanol and 2,2,2 tri-fluoroethanol: Hydrogen bonding structure and dynamics. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.10.129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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33
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Ghosh R, Bagchi B. Temperature Dependence of Static and Dynamic Heterogeneities in a Water–Ethanol Binary Mixture and a Study of Enhanced, Short-Lived Fluctuations at Low Concentrations. J Phys Chem B 2016; 120:12568-12583. [DOI: 10.1021/acs.jpcb.6b06001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rikhia Ghosh
- Solid State and
Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and
Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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34
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The role of OH…O and CH…O hydrogen bonds and H…H interactions in ethanol/methanol–water heterohexamers. J Mol Model 2016; 22:181. [DOI: 10.1007/s00894-016-3050-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/21/2016] [Indexed: 10/21/2022]
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Abstract
AbstractConcentration fluctuations play an important role in the statistical description of the stability of liquids, particularly in the neighborhood of phase transitions. Classical thermodynamics is blind to fluctuations, and statistical thermodynamics is required to fully understand quantities such as the isothermal compressibility or heat capacity, by linking them to fluctuations of appropriate statistical microscopic quantities and showing that they are response functions. This is illustrated by the seminal Kirkwood–Buff theory of solutions. However, the existence of micro-heterogeneous structures, particularly in aqueous mixtures, which leads to large Kirkwood–Buff integrals, suggest that micro-heterogeneity is a form of concentration fluctuation. This interpretation becomes difficult to accept when extrapolated to larger micro-heterogeneous structures such as micellar aggregates in micro-emulsions. By analyzing how different methods, experimental, computer experiments and theoretical approaches deal with the underlying duality behind these two physical manifestations, we put in evidence the need to reconsider the description of liquids by incorporating the description of emergent “objects”, such as the micro-heterogeneous structures from a molecular point of view. On this path, the concept of “molecular emulsion” allows to describe in a unified way all type of disordered liquids, from solutions to the organized liquids of soft matter.
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Affiliation(s)
- Aurélien Perera
- 1Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252, Paris cedex 05, France
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Oda Y, Sadakane K, Yoshikawa Y, Imanaka T, Takiguchi K, Hayashi M, Kenmotsu T, Yoshikawa K. Highly Concentrated Ethanol Solutions: Good Solvents for DNA as Revealed by Single-Molecule Observation. Chemphyschem 2016; 17:471-3. [PMID: 26891092 PMCID: PMC4770436 DOI: 10.1002/cphc.201500988] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 11/30/2022]
Abstract
We observed single DNA molecules at different ethanol concentrations by using fluorescence microscopy. Large single DNA molecules undergo reentrant conformational transitions from elongated coil into folded globule and then into elongated coil state, accompanied by the increase of the concentration of ethanol in a low‐salt aqueous environment. The second transition from globule into the coil state occurs at around 70 % (v/v) ethanol. From circular dichroism (CD) measurements, it is confirmed that the reentrant transition of the higher order structure proceeds together with the transitions of the secondary structure from B to C and, then, from C to A in a cooperative manner. The determined mechanism of the reentrant transition is discussed in relation to the unique characteristics of solutions with higher ethanol content, for which clathrate‐like nanostructures of alcohol molecules are generated in the surrounding water.
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Affiliation(s)
- Yuki Oda
- Faculty of Life and Medical Sciences, Doshisha University, Tatara, Miyakotani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Koichiro Sadakane
- Faculty of Life and Medical Sciences, Doshisha University, Tatara, Miyakotani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Yuko Yoshikawa
- Research Organization of Science and Technology, Ritsumeikan University, Nogihigashi, Kusatsu, Shiga, 525-8577, Japan
| | - Tadayuki Imanaka
- Research Organization of Science and Technology, Ritsumeikan University, Nogihigashi, Kusatsu, Shiga, 525-8577, Japan
| | - Kingo Takiguchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cyo, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Masahito Hayashi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cyo, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan
| | - Takahiro Kenmotsu
- Faculty of Life and Medical Sciences, Doshisha University, Tatara, Miyakotani, Kyotanabe, Kyoto, 610-0321, Japan
| | - Kenichi Yoshikawa
- Faculty of Life and Medical Sciences, Doshisha University, Tatara, Miyakotani, Kyotanabe, Kyoto, 610-0321, Japan.
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Požar M, Lovrinčević B, Zoranić L, Primorać T, Sokolić F, Perera A. Micro-heterogeneity versus clustering in binary mixtures of ethanol with water or alkanes. Phys Chem Chem Phys 2016; 18:23971-9. [DOI: 10.1039/c6cp04676b] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Snapshots of the difference in complex disorder, with analogy with direct (ethanol–water) and inverse (ethanol–alkanes) emulsions.
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Affiliation(s)
- Martina Požar
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600)
- Université Pierre et Marie Curie
- Paris cedex 05
- France
- Department of Physics
| | | | - Larisa Zoranić
- Department of Physics
- Faculty of Sciences
- University of Split
- Split
- Croatia
| | - Tomislav Primorać
- Department of Physics
- Faculty of Sciences
- University of Split
- Split
- Croatia
| | - Franjo Sokolić
- Department of Physics
- Faculty of Sciences
- University of Split
- Split
- Croatia
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600)
- Université Pierre et Marie Curie
- Paris cedex 05
- France
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38
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Ghosh R, Samajdar RN, Bhattacharyya AJ, Bagchi B. Composition dependent multiple structural transformations of myoglobin in aqueous ethanol solution: a combined experimental and theoretical study. J Chem Phys 2015; 143:015103. [PMID: 26156494 DOI: 10.1063/1.4923003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Experimental studies (circular dichroism and ultra-violet (UV) absorption spectra) and large scale atomistic molecular dynamics simulations (accompanied by order parameter analyses) are combined to establish a number of remarkable (and unforeseen) structural transformations of protein myoglobin in aqueous ethanol mixture at various ethanol concentrations. The following results are particularly striking. (1) Two well-defined structural regimes, one at xEtOH ∼ 0.05 and the other at xEtOH ∼ 0.25, characterized by formation of distinct partially folded conformations and separated by a unique partially unfolded intermediate state at xEtOH ∼ 0.15, are identified. (2) Existence of non-monotonic composition dependence of (i) radius of gyration, (ii) long range contact order, (iii) residue specific solvent accessible surface area of tryptophan, and (iv) circular dichroism spectra and UV-absorption peaks are observed. Interestingly at xEtOH ∼ 0.15, time averaged value of the contact order parameter of the protein reaches a minimum, implying that this conformational state can be identified as a molten globule state. Multiple structural transformations well known in water-ethanol binary mixture appear to have considerably stronger effects on conformation and dynamics of the protein. We compare the present results with studies in water-dimethyl sulfoxide mixture where also distinct structural transformations are observed along with variation of co-solvent composition.
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Affiliation(s)
- R Ghosh
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - R N Samajdar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | | | - B Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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SARKAR SARMISTHA, BANERJEE SAIKAT, ROY SUSMITA, GHOSH RIKHIA, RAY PARTHAPRATIM, BAGCHI BIMAN. Composition dependent non-ideality in aqueous binary mixtures as a signature of avoided spinodal decomposition. J CHEM SCI 2015. [DOI: 10.1007/s12039-014-0749-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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40
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Mijaković M, Polok KD, Kežić B, Sokolić F, Perera A, Zoranić L. A comparison of force fields for ethanol–water mixtures. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2014.923567] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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41
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Schulze PA, Dang NC, Bolme CA, Brown KE, McGrane SD, Moore DS. Shock Hugoniot Equations of State for Binary Ideal (Toluene/Fluorobenzene) and Nonideal (Ethanol/Water) Liquid Mixtures. J Phys Chem A 2013; 117:6158-63. [DOI: 10.1021/jp400310k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peter A. Schulze
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
| | - Nhan. C. Dang
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
| | - Cynthia A. Bolme
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
| | - Kathryn E. Brown
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
| | - Shawn D. McGrane
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
| | - David S. Moore
- Shock and Detonation Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545,
United States
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42
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Gerig JT. Investigation of Ethanol–Peptide and Water–Peptide Interactions through Intermolecular Nuclear Overhauser Effects and Molecular Dynamics Simulations. J Phys Chem B 2013; 117:4880-92. [DOI: 10.1021/jp4007526] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J. T. Gerig
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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44
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Kežić B, Perera A. Aqueous tert-butanol mixtures: a model for molecular-emulsions. J Chem Phys 2012; 137:014501. [PMID: 22779659 DOI: 10.1063/1.4730524] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By analogy with micro-emulsion, we introduce the molecular-emulsion picture to describe particular aqueous mixtures. The analogy is set by introducing the equivalent of the Teubner-Strey structure factor, the latter which is traditionally used to describe the structure of micro-emulsions. The main difference resides in the fact that the size of the oil and water domains are not in the micrometer, but in the nanometer scale. This implies that the molecular size and the molecular geometry cannot be neglected anymore. The introduction of this analogy is used to settle the problem of properly describing with computer simulations highly micro-heterogeneous aqueous mixtures. In particular, the issue of whether or not the Kirkwood-Buff integrals represent solely concentration fluctuations is settled by showing the contribution of the micro-heterogeneity to these integrals through the presence of an associated pre-peak in the structure factors. Both the Optimized Potentials for Liquid State (OPLS) and Transferable Potential for Phase Equilibria-United Atoms (TraPPE-UA) force fields for tert-butanol turn out to be remarkably good in describing the structure of the corresponding aqueous mixtures, when the above-mentioned analogy with micro-emulsion is introduced to correct for the computational artifacts in the Kirkwood-Buff integrals.
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Affiliation(s)
- Bernarda Kežić
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252 Paris cedex 05, France
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Kežić B, Perera A. Revisiting aqueous-acetone mixtures through the concept of molecular emulsions. J Chem Phys 2012; 137:134502. [DOI: 10.1063/1.4755816] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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46
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Gupta R, Patey GN. Aggregation in dilute aqueous tert-butyl alcohol solutions: Insights from large-scale simulations. J Chem Phys 2012; 137:034509. [DOI: 10.1063/1.4731248] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Perera A, Mazighi R, Kežić B. Fluctuations and micro-heterogeneity in aqueous mixtures. J Chem Phys 2012; 136:174516. [DOI: 10.1063/1.4707745] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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48
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Paul S, Patey GN. Influence of urea on tert-butyl alcohol aggregation in aqueous solutions. J Phys Chem B 2012; 116:4991-5001. [PMID: 22480288 DOI: 10.1021/jp300792p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ternary solutions consisting of urea, tert-butyl alcohol (TBA), and water are investigated employing molecular dynamics simulations. The main purpose of the present paper is to investigate the effect of urea on TBA aggregation and by extension its influence on hydrophobic interactions. The aggregation of TBA can be detected from the concentration dependence of structural properties such as first-shell TBA-water coordination numbers and TBA-TBA hydrogen-bond numbers, as well as through changes in the translational diffusion coefficients of TBA. It is found that urea acts to delay the association of TBA to concentrations greater than those required to cause TBA aggregation in binary TBA-water systems. It is shown that urea acts through a direct mechanism, whereby it preferentially binds to TBA replacing water from the first coordination shell. TBA-urea hydrogen bonds can be as strong as, or stronger than, those of TBA-water, and urea binds to both the hydrophilic and hydrophobic moieties of TBA. Our observations are qualitatively consistent with experimental results for urea-TBA-water solutions and with recent simulation studies of urea's action as a protein denaturant.
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Affiliation(s)
- Sandip Paul
- Department of Chemistry, Indian Institute of Technology , Guwahati, Assam, India-781039
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49
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Kežić B, Perera A. Towards a more accurate reference interaction site model integral equation theory for molecular liquids. J Chem Phys 2011; 135:234104. [DOI: 10.1063/1.3666006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Gupta R, Patey GN. Association and microheterogeneity in aqueous 2-butoxyethanol solutions. J Phys Chem B 2011; 115:15323-31. [PMID: 22082133 DOI: 10.1021/jp209905g] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Molecular dynamics simulations are employed to investigate aggregation and microheterogeneity in dilute solutions of 2-butoxyethanol (BE) in water. The BE concentration is varied from near infinite dilution to the mole fraction X(BE) = 0.04. It was found that large systems (32,000 molecules) are necessary to accommodate the BE aggregates that form in this concentration range. Simulations were performed with two different force fields, and similar results were obtained. At very low concentration, BE aggregation is not observed, but evidence is found for intramolecular hydrogen bonds (between the hydroxyl hydrogen and the ether oxygen of the same BE molecule) that form five-member ring configurations, similar to those reported in experimental studies of BE in nonaqueous solvent. Initial signs of BE association appear at X(BE) ≈ 0.005, after which aggregation occurs rapidly, with aggregates that can be described as micelle-like being fully formed at X(BE) ≈ 0.02. This concentration agrees well with many experimental studies of aggregation in BE-water solutions. Between X(BE) = 0.02 and 0.04, the aggregates appear to grow a little in size, but the basic structure remains the same. At long range, the various pair correlation functions show clear density oscillations associated with BE aggregation. This allows us to identify the length scales of the existing microheterogeneity and to estimate the size of the BE aggregates. If we assume spherical aggregates, then our estimate of the radius at X(BE) = 0.04 (~42 Å) is close to estimates obtained from light scattering and small-angle neutron scattering experiments.
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Affiliation(s)
- Rini Gupta
- Department of Chemistry, University of British Columbia, Vancouver BC, Canada, V6T 1Z1
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