1
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Sun Q, Chen YN, Liu YZ. The Effects of External Interfaces on Hydrophobic Interactions I: Smooth Surface. Molecules 2024; 29:3128. [PMID: 38999080 PMCID: PMC11243484 DOI: 10.3390/molecules29133128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/14/2024] Open
Abstract
External interfaces, such as the air-water and solid-liquid interfaces, are ubiquitous in nature. Hydrophobic interactions are considered the fundamental driving force in many physical and chemical processes occurring in aqueous solutions. It is important to understand the effects of external interfaces on hydrophobic interactions. According to the structural studies on liquid water and the air-water interface, the external interface primarily affects the structure of the topmost water layer (interfacial water). Therefore, an external interface may affect hydrophobic interactions. The effects of interfaces on hydrophobicity are related not only to surface molecular polarity but also to the geometric characteristics of the external interface, such as shape and surface roughness. This study is devoted to understanding the effects of a smooth interface on hydrophobicity. Due to hydrophobic interactions, the solutes tend to accumulate at external interfaces to maximize the hydrogen bonding of water. Additionally, these can be demonstrated by the calculated potential mean forces (PMFs) using molecular dynamic (MD) simulations.
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Affiliation(s)
- Qiang Sun
- Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, The School of Earth and Space Sciences, Peking University, Beijing 100871, China (Y.-Z.L.)
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2
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Panahian Jand S, Nourbakhsh Z, Delle Site L. Nuclear quantum effects in fullerene-fullerene aggregation in water. Front Chem 2022; 10:1072665. [PMID: 36590278 PMCID: PMC9799252 DOI: 10.3389/fchem.2022.1072665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/23/2022] [Indexed: 12/16/2022] Open
Abstract
We studied the effects of the quantum delocalization in space of the hydrogen atoms of water in the aggregation process of two fullerene molecules. We considered a case using a purely repulsive water-fullerene interaction, as such a situation has shown that water-mediated effects play a key role in the aggregation process. This study becomes feasible, at a reduced computational price, by combining the path integral (PI) molecular dynamics (MD) method with a recently developed open-system MD technique. Specifically, only the mandatory solvation shell of the two fullerene molecules was considered at full quantum resolution, while the rest of the system was represented as a mean-field macroscopic reservoir of particles and energy. Our results showed that the quantum nature of the hydrogen atoms leads to a sizable difference in the curve of the free energy of aggregation; that is, that nuclear quantum effects play a relevant role.
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3
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Zhu J, Cao X, Li J. Ethanol-Induced Aggregation of Nonpolar Nanoparticles in Water/Ethanol Mixed Solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13910-13915. [PMID: 36318107 DOI: 10.1021/acs.langmuir.2c02126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The dispersity of nonpolar nanoparticles (NPs) in water/ethanol mixed solvents was studied using molecular dynamics simulations. Based on the rule of "like dissolves like," nonpolar NPs should be dispersed better in a solvent with a lower polarity. As the mole fraction of ethanol in a mixed solvent (R) increases from 0% (pure water) to 100% (pure ethanol), the polarity of the mixed solvent is indicated to decrease monotonically. However, the dispersity of nonpolar NP does not increase monotonically: it first decreases after the addition of a small fraction of ethanol (R < 8.0%) and then markedly increases as R further grows. When there is a small amount of ethanol, the ethanol molecules around aggregated NPs tend to simultaneously make contact with multiple NPs, which can increase the tendency of NP aggregation. Furthermore, with a considerable ethanol ratio, the interaction of the solvent with NPs becomes notably strong, which facilitates the dissolution of NPs. Our findings may help to better understand the mechanism of dispersion of NPs in mixed solvents and may provide a useful precipitation technology for NP production.
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Affiliation(s)
- Jianzhuo Zhu
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao066004, China
| | - Xiaoyu Cao
- Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao066004, China
| | - Jingyuan Li
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Institute of Quantitative Biology, Department of Physics, Zhejiang University, Hangzhou310027, China
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4
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Sumi T, Imamura H. Water-mediated interactions destabilize proteins. Protein Sci 2021; 30:2132-2143. [PMID: 34382697 PMCID: PMC8442971 DOI: 10.1002/pro.4168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 01/29/2023]
Abstract
Proteins are folded to avoid exposure of the nonpolar groups to water because water-mediated interactions between nonpolar groups are a promising factor in the thermodynamic stabilities of proteins-which is a well-accepted view as one of the unique effects of hydrophobic interactions. This article poses a critical question for this classical view by conducting an accurate solvation free-energy calculation for a thermodynamic cycle of a protein folding using a liquid-state density functional theory. Here, the solvation-free energy for a leucine zipper formation was examined in the coiled-coil protein GCN4-p1, a typical model for hydrophobic interactions, which demonstrated that water-mediated interactions were unfavorable for the association of nonpolar groups in the native state, while the dispersion forces between them were, instead, responsible for the association. Furthermore, the present analysis well predicted the isolated helical state stabilized by pressure, which was previously observed in an experiment. We reviewed the problems in the classical concept and semiempirical presumption that the energetic cost of the hydration of nonpolar groups is a driving force of folding.
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Affiliation(s)
- Tomonari Sumi
- Research Institute for Interdisciplinary ScienceOkayama UniversityKita‐kuJapan
- Department of Chemistry, Faculty of ScienceOkayama UniversityKita‐kuJapan
| | - Hiroshi Imamura
- Department of Applied Chemistry, College of Life SciencesRitsumeikan UniversityKusatsuJapan
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5
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Kim YJ, Loeffler TD, Chen Z, Sankaranarayanan SKRS. Promoting Noncovalent Intermolecular Interactions Using a C 60 Core Particle in Aqueous PC60s-Covered Colloids for Ultraefficient Photoinduced Particle Activity. ACS APPLIED MATERIALS & INTERFACES 2019; 11:38798-38807. [PMID: 31558014 DOI: 10.1021/acsami.9b14240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Noncovalent intermolecular interactions in nanomaterials, such as van der Waals effects, allow adjustment of the nanoscopic size of compounds and their conformation in molecular crystal regimes. These strong interactions permit small particle sizes to be maintained as the crystals grow. In particular, these effects can be leveraged in the confined/reinforcing phase of molecules. With this in mind, we used C60 molecules as a core particle in single-PC60 surfactant-covered colloid in a water-processable system. Compared with our previous results based on a PC61BM core-PC60 shell particle, the PC60-C60 colloid had a considerably smaller spherical structure due to the increased intermolecular interactions between C60 (fullerene) molecules. Interestingly, the conformation of C60 aggregates was altered depending on the mixed solvents and their volume fraction in the organic phase, which strongly affected the structural properties of the PC60-C60 colloids. The particle facilitated strong interactions with a p-type core sphere when it was introduced as the shell part of a p-n heterojunction particle. This direct interaction provided effective electronic communication between p- and n-type particles, resulting in ultraefficient photonic properties, particularly in charge separation in aqueous heterostructured colloids. This enabled the development of an extremely efficient photovoltaic device with a 6.74% efficiency, which could provide the basis for creating high-performance water-processable solar cells based on p-n heterostructured NPs.
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Affiliation(s)
- Yu Jin Kim
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Troy D Loeffler
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Zhaowei Chen
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
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6
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Sumi T, Koga K. Theoretical analysis on thermodynamic stability of chignolin. Sci Rep 2019; 9:5186. [PMID: 30914684 PMCID: PMC6435801 DOI: 10.1038/s41598-019-41518-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/11/2019] [Indexed: 11/28/2022] Open
Abstract
Understanding the dominant factor in thermodynamic stability of proteins remains an open challenge. Kauzmann's hydrophobic interaction hypothesis, which considers hydrophobic interactions between nonpolar groups as the dominant factor, has been widely accepted for about sixty years and attracted many scientists. The hypothesis, however, has not been verified or disproved because it is difficult, both theoretically and experimentally, to quantify the solvent effects on the free energy change in protein folding. Here, we developed a computational method for extracting the dominant factor behind thermodynamic stability of proteins and applied it to a small, designed protein, chignolin. The resulting free energy profile quantitatively agreed with the molecular dynamics simulations. Decomposition of the free energy profile indicated that intramolecular interactions predominantly stabilized collapsed conformations, whereas solvent-induced interactions, including hydrophobic ones, destabilized them. These results obtained for chignolin were consistent with the site-directed mutagenesis and calorimetry experiments for globular proteins with hydrophobic interior cores.
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Affiliation(s)
- Tomonari Sumi
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan.
- Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan.
| | - Kenichiro Koga
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
- Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
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7
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Lam J, Lutsko JF. Solvent-mediated interactions between nanostructures: From water to Lennard-Jones liquid. J Chem Phys 2018; 149:134703. [PMID: 30292194 DOI: 10.1063/1.5037571] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Solvent-mediated interactions emerge from complex mechanisms that depend on the solute structure, its wetting properties, and the nature of the liquid. While numerous studies have focused on the first two influences, here, we compare the results from water and Lennard-Jones liquid in order to reveal to what extent solvent-mediated interactions are universal with respect to the nature of the liquid. Besides the influence of the liquid, the results were obtained with classical density functional theory and brute-force molecular dynamics simulations which allow us to contrast these two numerical techniques.
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Affiliation(s)
- Julien Lam
- Center for Nonlinear Phenomena and Complex Systems, Universite Libre de Bruxelles, Code Postal 231, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - James F Lutsko
- Center for Nonlinear Phenomena and Complex Systems, Universite Libre de Bruxelles, Code Postal 231, Boulevard du Triomphe, 1050 Brussels, Belgium
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8
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Nakamura H, Nozaki Y, Koizumi Y, Watano S. Effect of number of hydroxyl groups of fullerenol C 60 (OH) n on its interaction with cell membrane. J Taiwan Inst Chem Eng 2018. [DOI: 10.1016/j.jtice.2017.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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9
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Thermodynamics of association of water soluble fullerene derivatives [ $$\hbox {C}_{60}\hbox {(OH)}_{\mathrm{n}}$$ C 60 (OH) n , n = 0, 2, 4, 8 and 12] in aqueous media. J CHEM SCI 2017. [DOI: 10.1007/s12039-017-1356-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Keshri S, Tembe BL. Thermodynamics of hydration of fullerols [C 60(OH) n] and hydrogen bond dynamics in their hydration shells. J Chem Phys 2017; 146:074501. [PMID: 28228041 DOI: 10.1063/1.4975230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Molecular dynamics simulations of fullerene and fullerols [C60(OH)n, where n = 2-30] in aqueous solutions have been performed for the purpose of obtaining a detailed understanding of the structural and dynamic properties of these nanoparticles in water. The structures, dynamics and hydration free energies of the solute molecules in water have been analysed. Radial distribution functions, spatial density distribution functions and hydrogen bond analyses are employed to characterize the solvation shells of water around the central solute molecules. We have found that water molecules form two solvation shells around the central solute molecule. Hydrogen bonding in the bulk solvent is unaffected by increasing n. The large decrease in solvation enthalpies of these solute molecules for n > 14 enhances solubilisation. The diffusion constants of solute molecules decrease with increasing n. The solvation free energy of C60 in water is positive (52.8 kJ/mol), whereas its value for C60(OH)30 is highly negative (-427.1 kJ/mol). The effects of surface hydroxylation become more dominant once the fullerols become soluble.
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Affiliation(s)
- Sonanki Keshri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - B L Tembe
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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11
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Makarucha AJ, Baldauf JS, Downton MT, Yiapanis G. Size-Dependent Fullerene–Fullerene Interactions in Water: A Molecular Dynamics Study. J Phys Chem B 2016; 120:11018-11025. [DOI: 10.1021/acs.jpcb.6b07471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adam J. Makarucha
- IBM Research Australia, 204 Lygon Street, Carlton VIC 3053, Australia
| | - Julia S. Baldauf
- IBM Research Australia, 204 Lygon Street, Carlton VIC 3053, Australia
| | | | - George Yiapanis
- IBM Research Australia, 204 Lygon Street, Carlton VIC 3053, Australia
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12
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Affiliation(s)
- Chun I Wang
- Department
of Chemical Engineering, National Chung Cheng University, Chia-Yi 62102, Taiwan R.O.C
| | - Chi C. Hua
- Department
of Chemical Engineering, National Chung Cheng University, Chia-Yi 62102, Taiwan R.O.C
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13
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Accordino SR, Montes de Oca JM, Rodriguez Fris JA, Appignanesi GA. Hydrophilic behavior of graphene and graphene-based materials. J Chem Phys 2015; 143:154704. [DOI: 10.1063/1.4933011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sebastián R. Accordino
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Joan Manuel Montes de Oca
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - J. Ariel Rodriguez Fris
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina
| | - Gustavo A. Appignanesi
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina
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14
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Varanasi SR, Guskova OA, John A, Sommer JU. Water around fullerene shape amphiphiles: A molecular dynamics simulation study of hydrophobic hydration. J Chem Phys 2015; 142:224308. [DOI: 10.1063/1.4922322] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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15
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Djikaev YS, Ruckenstein E. Effect of Water Hydrogen Bonding on the Solvent-Mediated "Oscillatory" Repulsion of C60 Fullerenes in Water. J Phys Chem Lett 2015; 6:1761-1766. [PMID: 26263346 DOI: 10.1021/acs.jpclett.5b00508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The solvent-mediated interaction of C60 fullerenes in liquid water is examined by using the combination of the probabilistic hydrogen bond model with the density functional theory. This combination allows one to take into account the effect of hydrogen bonding between water molecules on their interaction with fullerenes and to construct an approximation for the distribution of water molecules in the system, which provides an efficient foundation for studying hydrophobic phenomena. Our numerical evaluations predict the solvent-induced interaction of two C60 fullerenes in water at 293 K to have an oscillatory-repulsive character (previously observed in molecular dynamics simulations) only when the vicinal water-water hydrogen bonds are slightly weaker than bulk ones. Besides indicating the direction of the energetic alteration of water-water hydrogen bonds near C60 fullerenes, our model also suggests that the hydrogen bonding ability of water plays a defining role in the solvent-mediated C60-C60 repulsion.
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Affiliation(s)
- Yuri S Djikaev
- Department of Chemical and Biological Engineering, SUNY at Buffalo, Buffalo, New York 14260, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, SUNY at Buffalo, Buffalo, New York 14260, United States
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16
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Choi JI, Snow SD, Kim JH, Jang SS. Interaction of C₆₀ with water: first-principles modeling and environmental implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:1529-1536. [PMID: 25602529 DOI: 10.1021/es504614u] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The nature of fullerene-water interactions has been the subject of much research and debate. Specifically, the presence of a stabilizing, negative surface potential on colloidal aggregates of C60 in water is unexpected, given the neutral nature of pure carbon, and is not well understood. Previous simulation efforts have focused on the C60-water interaction using molecular dynamics simulations that lacked the ability to account for charge transfer and distribution interactions. In this study, first-principles density functional theory was used to analyze the fundamental electronic interactions to elucidate the polarization and charge transfer between water and C60. Simulations show that charge is inductively transferred to the C60 from water molecules, with subsequent polarization of the C60 molecule. In a case with two neighboring C60 molecules, the charge polarization induces a charge onto the second C60. Simulation suggests that this charge transfer and polarization may contribute at least partly to the observed negative surface potential of fullerene aggregates and, combined with hydrogen bonding network formation around C60, provides a fundamental driving force for aggregate formation in water.
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Affiliation(s)
- Ji Il Choi
- Computational NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0245, United States
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17
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Bartosik A, Wiśniewska M, Makowski M. Potentials of mean force for hydrophobic interactions between hydrocarbons in water solution: dependence on temperature, solute shape, and solute size. J PHYS ORG CHEM 2014. [DOI: 10.1002/poc.3387] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Angelika Bartosik
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Marta Wiśniewska
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Mariusz Makowski
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
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18
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Affiliation(s)
- Ronen Zangi
- Department of Organic Chemistry
I, University of the Basque Country UPV/EHU, Avenida de Tolosa 72, 20018 San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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19
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Wang CI, Hua CC, Chen SA. Dynamic solvation shell and solubility of C60 in organic solvents. J Phys Chem B 2014; 118:9964-73. [PMID: 25084556 DOI: 10.1021/jp506572p] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The notion of (static) solvation shells has recently proved fruitful in revealing key molecular factors that dictate the solubility and aggregation properties of fullerene species in polar or ionic solvent media. Using molecular dynamics schemes with carefully evaluated force fields, we have scrutinized both the static and the dynamic features of the solvation shells of single C60 particle for three nonpolar organic solvents (i.e., chloroform, toluene, and chlorobenzene) and a range of system temperatures (i.e., T = 250-330 K). The central findings have been that, while the static structures of the solvation shell remain, in general, insensitive to the effects of changing solvent type or system temperature, the dynamic behavior of solvent molecules within the shell exhibits prominent dependence on both factors. Detailed analyses led us to propose the notion of dynamically stable solvation shell, effectiveness of which can be characterized by a new physical parameter defined as the ratio of two fundamental time constants representing, respectively, the solvent relaxation (or residence) time within the first solvation shell and the characteristic time required for the fullerene particle to diffuse a distance comparable to the shell thickness. We show that, for the five (two from the literature) different solvent media and the range of system temperatures examined herein, this parameter bears a value around unity and, in particular, correlates intimately with known trends of solubility for C60 solutions. We also provide evidence revealing that, in addition to fullerene-solvent interactions, solvent-solvent interactions play an important role, too, in shaping the dynamic solvation shell, as implied by recent experimental trends.
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Affiliation(s)
- Chun I Wang
- Department of Chemical Engineering, National Chung Cheng University , Chia-Yi 62102, Taiwan, Republic of China
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20
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Affiliation(s)
- Lauren J. Abbott
- Department
of Materials Science
and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Coray M. Colina
- Department
of Materials Science
and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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21
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Mortuza SM, Banerjee S. Molecular modeling study of agglomeration of [6,6]-phenyl-C61-butyric acid methyl ester in solvents. J Chem Phys 2012; 137:244308. [DOI: 10.1063/1.4772759] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Ensing B, Costanzo F, Silvestrelli PL. On the Polarity of Buckminsterfullerene with a Water Molecule Inside. J Phys Chem A 2012; 116:12184-8. [PMID: 23157158 DOI: 10.1021/jp311161q] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Bernd Ensing
- Van’t Hoff Institute
for Molecular Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Francesca Costanzo
- Dipartimento di Fisica e Astronomia
“G. Galilei”, Universita’ di Padova, via Marzolo 8, I-35131 Padova, Italy
| | - Pier Luigi Silvestrelli
- Dipartimento di Fisica e Astronomia
“G. Galilei”, Universita’ di Padova, via Marzolo 8, I-35131 Padova, Italy
- DEMOCRITOS National Simulation Center, Trieste, Italy
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23
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Rana MK, Chandra A. Solvation of fullerene and fulleride ion in liquid ammonia: Structure and dynamics of the solvation shells. J Chem Phys 2012; 137:134501. [DOI: 10.1063/1.4754852] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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24
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A molecular simulation of interactions between graphene nanosheets and supercritical CO2. J Colloid Interface Sci 2011; 361:1-8. [DOI: 10.1016/j.jcis.2011.05.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 05/06/2011] [Accepted: 05/08/2011] [Indexed: 11/20/2022]
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25
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Egorov SA. Hydrophobic interactions with coarse-grained model for water. J Chem Phys 2011; 134:234509. [DOI: 10.1063/1.3602217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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26
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27
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Li J, Garg M, Shah D, Rajagopalan R. Solubilization of aromatic and hydrophobic moieties by arginine in aqueous solutions. J Chem Phys 2010; 133:054902. [DOI: 10.1063/1.3469790] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Ma X, Wigington B, Bouchard D. Fullerene C60: surface energy and interfacial interactions in aqueous systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11886-11893. [PMID: 20521798 DOI: 10.1021/la101109h] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The underlying mechanisms of fullerene-fullerene, fullerene-water, and fullerene-soil surface interactions in aqueous systems are not well understood. To advance our understanding of these interfacial interactions, the surface properties of Buckminsterfullerene (C60) and quartz surfaces were investigated. From application of the van Oss-Chaudhury-Good model and the Young-Dupre equation, the Lifshitz-van der Waals, acid-base, and the total surface energies of C60 powder and quartz surfaces were calculated from contact angle measurements using the sessile drop technique. C60 powder measurements indicate low to medium energy surfaces of 41.7 mJ/m2 with a dominant Lifshitz-van der Waals component. In aqueous systems, hydrophobic attraction due to the high cohesion of water is the driving force for C60 aggregation. The high free energy of hydration (DeltaG(pw)(total) = -90.5 mJ/m2) indicates the high affinity of C60 particles for water. Hamaker constants of 4.02 x 10(-21) J (A(pwp)) and 2.59 x 10(-21) J (A(pws)) were derived for C60-C60 and C60-quartz interactions in aqueous systems. The results of this study indicate that surface energy is an important physical parameter that should be considered as a basic characterization property of fullerene nanomaterials.
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Affiliation(s)
- Xin Ma
- USEPA Office of Research and Development, National Exposure Research Laboratory, Athens, Georgia 30605, USA
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Chiu CC, DeVane R, Klein ML, Shinoda W, Moore PB, Nielsen SO. Coarse-Grained Potential Models for Phenyl-Based Molecules: II. Application to Fullerenes. J Phys Chem B 2010; 114:6394-400. [DOI: 10.1021/jp9117375] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chi-cheng Chiu
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
| | - Russell DeVane
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
| | - Michael L. Klein
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
| | - Wataru Shinoda
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
| | - Preston B. Moore
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
| | - Steven O. Nielsen
- Department of Chemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, Institute for Computational Molecular Science and Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan, and Department of Chemistry & Biochemistry, University of the
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Makowski M, Czaplewski C, Liwo A, Scheraga HA. Potential of mean force of association of large hydrophobic particles: toward the nanoscale limit. J Phys Chem B 2010; 114:993-1003. [PMID: 20039620 DOI: 10.1021/jp907794h] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potentials of mean force (PMFs) were determined, in both water with the TIP3P water model and in vacuo, for systems involving formation of nonpolar dimers composed of bicyclooctane, adamantane (both an all-atom model and a sphere with the radius of 3.4 A representing adamantane), and fullerene, respectively. A series of umbrella-sampling molecular dynamics simulations with the AMBER force field were carried out for each pair under both environmental conditions. The PMFs were calculated by using the weighted histogram analysis method. The results were compared with our previously determined PMF for neopentane. The shape of the PMFs for dimers of all four nonpolar molecules is characteristic of hydrophobic interactions with contact and solvent-separated minima and desolvation maxima. The positions of all these minima and maxima change with the size of the nonpolar molecule; for larger molecules they shift toward larger distances. Comparison of the PMFs of the bicyclooctane, adamantane, and fullerene dimers in water and in vacuo shows that hydrophobic interactions in each dimer are different from that for the dimer of neopentane. Interactions in the bicyclooctane, adamantane, and fullerene dimers are stronger in vacuo than in water. These dimers cannot be treated as classical, spherical, hydrophobic objects. The solvent contribution to the PMF was also computed by subtracting the PMF determined in vacuo from that in explicit solvent. The solvent contribution to the PMFs of bicyclooctane, adamantane, and fullerene is positive, as opposed to that of neopentane. The water molecules in the first solvation sphere of both adamantane and neopentane dimers are more ordered as compared to bulk water, with their dipole moments pointing away from the surface of the dimers. The average number of hydrogen bonds per water molecule in the first hydration shell of adamantane is smaller compared to that in bulk water, but this shell is thicker for all-atom adamantane than for neopentane or a spherical model of adamantane. In the second hydration shell, the average number of hydrogen bonds is greater compared to that in bulk water only for neopentane and a spherical model of adamantane but not for the all-atom model. The strength of the hydrophobic interactions shows a linear dependence on the number of carbon atoms both in water and in vacuo. Smaller nonpolar particles interact more strongly in water than in vacuo. For larger molecules, such as bicyclooctane, adamantane and fullerene, the reversed tendency is observed.
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Affiliation(s)
- Mariusz Makowski
- Faculty of Chemistry, University of Gdańsk, ul. Sobieskiego 18, 80-952 Gdańsk, Poland.
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Maciel C, Fileti EE, Rivelino R. Note on the Free Energy of Transfer of Fullerene C60 Simulated by Using Classical Potentials. J Phys Chem B 2009; 113:7045-8. [DOI: 10.1021/jp902265a] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cleiton Maciel
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-270 Santo André, SP, Brazil
| | - Eudes E. Fileti
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-270 Santo André, SP, Brazil
| | - Roberto Rivelino
- Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, BA, Brazil
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32
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Hooper JB, Bedrov D, Smith GD. The influence of polymer architecture on the assembly of poly(ethylene oxide) grafted C60 fullerene clusters in aqueous solution: a molecular dynamics simulation study. Phys Chem Chem Phys 2009; 11:2034-45. [DOI: 10.1039/b818971d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wong-Ekkabut J, Baoukina S, Triampo W, Tang IM, Tieleman DP, Monticelli L. Computer simulation study of fullerene translocation through lipid membranes. NATURE NANOTECHNOLOGY 2008; 3:363-8. [PMID: 18654548 DOI: 10.1038/nnano.2008.130] [Citation(s) in RCA: 347] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 04/21/2008] [Indexed: 05/20/2023]
Abstract
Recent toxicology studies suggest that nanosized aggregates of fullerene molecules can enter cells and alter their functions, and also cross the blood-brain barrier. However, the mechanisms by which fullerenes penetrate and disrupt cell membranes are still poorly understood. Here we use computer simulations to explore the translocation of fullerene clusters through a model lipid membrane and the effect of high fullerene concentrations on membrane properties. The fullerene molecules rapidly aggregate in water but disaggregate after entering the membrane interior. The permeation of a solid-like fullerene aggregate into the lipid bilayer is thermodynamically favoured and occurs on the microsecond timescale. High concentrations of fullerene induce changes in the structural and elastic properties of the lipid bilayer, but these are not large enough to mechanically damage the membrane. Our results suggest that mechanical damage is an unlikely mechanism for membrane disruption and fullerene toxicity.
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Affiliation(s)
- Jirasak Wong-Ekkabut
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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Hooper JB, Bedrov D, Smith GD. Supramolecular self-organization in PEO-modified C60 fullerene/water solutions: influence of polymer molecular weight and nanoparticle concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:4550-4557. [PMID: 18402490 DOI: 10.1021/la703057y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Utilizing a first-principles-based coarse-grained implicit solvent model, we have investigated the self-association of C(60) fullerenes that have been symmetrically modified with six grafted poly(ethylene oxide) (PEO) chains in aqueous solution. Despite the highly symmetric nature of the pair interactions between PEO-grafted fullerenes, their supramolecular assemblies are highly anisotropic and resemble the linear clusters formed in Stockmayer fluids. The dipole-like interaction between these symmetrically modified fullerenes results from the shielding of the C(60) fullerenes by PEO, favoring the addition of more PEO-grafted fullerenes to the linear clusters at the relatively unprotected ends. At low nanoparticle concentrations, self-association is dominated by the formation of stable dimers and trimers resulting from fullerene-fullerene contact and favorable PEO-fullerene interactions. With increasing nanoparticle concentration, larger clusters become increasingly probable. The molecular weight of the PEO tethers can be treated as a temperature-like analogue, with a reduction in average cluster size with increasing chain length due to increased steric repulsion, which is qualitatively similar to effects observed in Stockmayer fluids with increasing temperature. The role of PEO in supramolecular self-organization in PEO-modified C(60) fullerene/water solutions is complex, contributing not only to steric stabilization but also to favorable energetic interactions, nanoparticle shielding, and depletion-driven aggregation.
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Affiliation(s)
- Justin B Hooper
- Department of Materials Science and Engineering, University of Utah, 122 S. Central Campus Drive Rm. 304, Salt Lake City, Utah 84112, USA.
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36
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Fang KC, Weng CI. Molecular dynamics simulations of structural features and diffusion properties of fullerene-in-water suspensions. J Colloid Interface Sci 2008; 318:188-94. [DOI: 10.1016/j.jcis.2007.10.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 10/17/2007] [Accepted: 10/25/2007] [Indexed: 11/17/2022]
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37
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Kim H, Bedrov D, Smith GD. Molecular Dynamics Simulation Study of the Influence of Cluster Geometry on Formation of C60 Fullerene Clusters in Aqueous Solution. J Chem Theory Comput 2008; 4:335-40. [DOI: 10.1021/ct700211y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hojin Kim
- Departments of Chemical Engineering and Materials Science and Engineering, 122 South Central Campus Drive Room 304, University of Utah, Salt Lake City, Utah 84112
| | - Dmitry Bedrov
- Departments of Chemical Engineering and Materials Science and Engineering, 122 South Central Campus Drive Room 304, University of Utah, Salt Lake City, Utah 84112
| | - Grant D. Smith
- Departments of Chemical Engineering and Materials Science and Engineering, 122 South Central Campus Drive Room 304, University of Utah, Salt Lake City, Utah 84112
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The Sequential qm/mm Method and its Applications to Solvent Effects in Electronic and Structural Properties of Solutes. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2008. [DOI: 10.1007/978-1-4020-8270-2_7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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39
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Malaspina T, Fileti EE, Rivelino R. Structure and UV−Vis Spectrum of C60 Fullerene in Ethanol: A Sequential Molecular Dynamics/Quantum Mechanics Study. J Phys Chem B 2007; 111:11935-9. [PMID: 17892279 DOI: 10.1021/jp0746244] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A molecular dynamics simulation combined with semiempirical quantum mechanics calculations has been performed to investigate the structure, dynamical, and electronic properties of pure C60 in liquid ethanol. The behavior of the fullerene alcoholic solution was obtained by using the NPT ensemble under ambient conditions, including one C60 fullerene immersed in 1000 ethanol molecules. Our analyzed center-of-mass pairwise radial distribution function indicated that, on average, there are 32, 72, 132, and 187 ethanol molecules around, respectively, the first, second, third, and fourth solvation shells of the C60 molecule. To investigate the UV-vis transition energies of C60 in the presence of ethanol, we have considered constituents of the time uncorrelated supramolecular structures of the first solvation shell, i.e., clusters of C60@{EtOH}32 types. The semiempirical calculations were performed at the intermediate neglect of differential overlap level with configuration interaction singles (INDO/CIS). Our results have pointed out that the characteristic C60 UV-vis absorbance peaks are slightly shifted to longer wavelengths, as compared to the isolated molecule. These findings are in connection with the weak donor-acceptor character of the interactions involving electron lone pairs of oxygen atoms on the solvent and the fullerene surface.
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Affiliation(s)
- Thaciana Malaspina
- Instituto de Química, Universidade de São Paulo, 05513-970, São Paulo, SP, Brazil
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40
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Cheng LT, Dzubiella J, McCammon JA, Li B. Application of the level-set method to the implicit solvation of nonpolar molecules. J Chem Phys 2007; 127:084503. [PMID: 17764265 DOI: 10.1063/1.2757169] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A level-set method is developed for numerically capturing the equilibrium solute-solvent interface that is defined by the recently proposed variational implicit solvent model [Dzubiella, Swanson, and McCammon, Phys. Rev. Lett. 104, 527 (2006); J. Chem. Phys. 124, 084905 (2006)]. In the level-set method, a possible solute-solvent interface is represented by the zero level set (i.e., the zero level surface) of a level-set function and is eventually evolved into the equilibrium solute-solvent interface. The evolution law is determined by minimization of a solvation free energy functional that couples both the interfacial energy and the van der Waals type solute-solvent interaction energy. The surface evolution is thus an energy minimizing process, and the equilibrium solute-solvent interface is an output of this process. The method is implemented and applied to the solvation of nonpolar molecules such as two xenon atoms, two parallel paraffin plates, helical alkane chains, and a single fullerence C(60). The level-set solutions show good agreement for the solvation energies when compared to available molecular dynamics simulations. In particular, the method captures solvent dewetting (nanobubble formation) and quantitatively describes the interaction in the strongly hydrophobic plate system.
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Affiliation(s)
- Li-Tien Cheng
- Department of Mathematics, University of California, San Diego, La Jolla, California 92093-0112, USA.
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41
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Athawale MV, Goel G, Ghosh T, Truskett TM, Garde S. Effects of lengthscales and attractions on the collapse of hydrophobic polymers in water. Proc Natl Acad Sci U S A 2007; 104:733-8. [PMID: 17215352 PMCID: PMC1766333 DOI: 10.1073/pnas.0605139104] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present results from extensive molecular dynamics simulations of collapse transitions of hydrophobic polymers in explicit water focused on understanding effects of lengthscale of the hydrophobic surface and of attractive interactions on folding. Hydrophobic polymers display parabolic, protein-like, temperature-dependent free energy of unfolding. Folded states of small attractive polymers are marginally stable at 300 K and can be unfolded by heating or cooling. Increasing the lengthscale or decreasing the polymer-water attractions stabilizes folded states significantly, the former dominated by the hydration contribution. That hydration contribution can be described by the surface tension model, DeltaG = gamma(T)DeltaA, where the surface tension, gamma, is lengthscale-dependent and decreases monotonically with temperature. The resulting variation of the hydration entropy with polymer lengthscale is consistent with theoretical predictions of Huang and Chandler [Huang DM, Chandler D (2000) Proc Natl Acad Sci USA 97:] that explain the blurring of entropy convergence observed in protein folding thermodynamics. Analysis of water structure shows that the polymer-water hydrophobic interface is soft and weakly dewetted, and is characterized by enhanced interfacial density fluctuations. Formation of this interface, which induces polymer folding, is strongly opposed by enthalpy and favored by entropy, similar to the vapor-liquid interface.
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Affiliation(s)
- Manoj V. Athawale
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180; and
| | - Gaurav Goel
- Department of Chemical Engineering and Institute for Theoretical Chemistry, University of Texas, Austin, TX 78712
| | - Tuhin Ghosh
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180; and
| | - Thomas M. Truskett
- Department of Chemical Engineering and Institute for Theoretical Chemistry, University of Texas, Austin, TX 78712
- To whom correspondence may be addressed. E-mail:
or
| | - Shekhar Garde
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180; and
- To whom correspondence may be addressed. E-mail:
or
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Choudhury N. A molecular dynamics simulation study of buckyballs in water: Atomistic versus coarse-grained models of C60. J Chem Phys 2006; 125:34502. [PMID: 16863357 DOI: 10.1063/1.2217442] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A simple coarse-grained water-C(60) model potential is proposed to study the solvation behavior of C(60) in water. Extensive molecular dynamics simulations are performed to compare the hydration behavior of the coarse-grained C(60) with that of its atomistic counterpart. In the coarse-grained description, we model the C(60) as a spherical solute and its interaction with water is represented by a simple two-body central potential as obtained from a coarse graining of the interactions of a water molecule with all the atoms of the C(60). On the other hand, the atomistic model takes into account a discrete nature of all the atoms of C(60) explicitly. Molecular dynamics simulations are carried out in an isothermal-isobaric ensemble at normal temperature and pressure. Various spatial and orientational correlations of the water around the two model C(60)s are compared. The coarse-grained model is shown to reproduce the hydration behavior of the C(60) quite well. The simplicity and the computational economy of the coarse-grained model will allow for simulations of self-assembly processes of a much larger system over a longer period of time.
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Affiliation(s)
- Niharendu Choudhury
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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Bedrov D, Smith GD. Molecular dynamics simulation study of the structure of poly(ethylene oxide) brushes on nonpolar surfaces in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:6189-94. [PMID: 16800675 DOI: 10.1021/la060535r] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The structure of poly(ethylene oxide) (PEO, M(w) = 526) brushes of various grafting density (sigma) on nonpolar graphite and hydrophobic (oily) surfaces in aqueous solution has been studied using atomistic molecular dynamics simulations. Additionally, the influence of PEO-surface interactions on the brush structure was investigated by systematically reducing the strength of the (dispersion) attraction between PEO and the surfaces. PEO chains were found to adsorb strongly to the graphite surface due primarily to the relative strength of dispersion interactions between PEO and the atomically dense graphite compared to those between water and graphite. For the oily surface, PEO-surface and water-surface dispersion interactions are much weaker, greatly reducing the energetic driving force for PEO adsorption. This reduction is mediated to some extent by a hydrophobic driving force for PEO adsorption on the oily surface. Reduction in the strength of PEO-surface attraction results in reduced adsorption of PEO for both surfaces, with the effect being much greater for the graphite surface where the strong PEO-surface dispersion interactions dominate. At high grafting density (sigma approximately 1/R(g)(2)), the PEO density profiles exhibited classical brush behavior and were largely independent of the strength of the PEO-surface interaction. With decreasing grafting density (sigma < 1/R(g)(2)), coverage of the surface by PEO requires an increasingly large fraction of PEO segments resulting in a strong dependence of the PEO density profile on the nature of the PEO-surface interaction.
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Affiliation(s)
- Dmitry Bedrov
- Department of Material Science & Engineering, University of Utah, Salt Lake City, Utah 84112, USA
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Zhou S. Formalism for calculation of polymer-solvent-mediated potential. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:011402. [PMID: 16907091 DOI: 10.1103/physreve.74.011402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Indexed: 05/11/2023]
Abstract
A simple theoretical approach is proposed for calculation of a solvent-mediated potential (SMP) between two colloid particles immersed in a polymer solvent bath in which the polymer is modeled as a chain with intramolecular degrees of freedom. The present recipe is only concerned with the estimation of the density profile of a polymer site around a single solute colloid particle instead of two solute colloid particles separated by a varying distance as done in existing calculational methods for polymer-SMP. Therefore the present recipe is far simpler for numerical implementation than the existing methods. The resultant predictions for the polymer-SMP and polymer solvent-mediated mean force (polymer-SMMF) are in very good agreement with available simulation data. With the present recipe, change tendencies of the contact value and second virial coefficiency of the SMP as a function of size ratio between the colloid particle and polymer site, the number of sites per chain, and the polymer concentration are investigated in detail. The metastable critical polymer concentration as a function of size ratio and the number of sites per chain is also reported for the first time. To yield the numerical solution of the present recipe at less than on a personal computer, a rapid and accurate algorithm for the numerical solution of the classical density functional theory is proposed to supply rapid and accurate estimation of the density profile of the polymer site as an input into the present formalism.
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Affiliation(s)
- Shiqi Zhou
- Institute of Modern Statistical Mechanics, Hunan University of Technology, Wenhua Road, Zhuzhou City, 412008, People's Republic of China.
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Abstract
Molecular dynamics simulations were carried out in order to study the hydration of C60 fullerenes, carbon nanotubes, and graphene sheets in aqueous solution and the nature of water-induced interactions between these carbon nanoparticles. The hydration of these nonpolar carbon nanoparticles does not exhibit classical hydrophobic character due to the high density of surface atoms (carbon) resulting in strong water-surface dispersion interactions. Water was found to wet the nanoparticle surfaces independent of nanoparticle surface curvature, with the decrease in the extent of water-water hydrogen bonding with decreasing surface curvature being offset by stronger water-surface interactions. While all carbon nanoparticles investigated are anticipated to aggregate in water due to strong direct nanoparticle-nanoparticle interactions, the water-induced interactions between nanoparticles were found to be repulsive and, in contrast to the wetting behavior, were observed to exhibit strong dependence on surface curvature. The strength of the water-induced interaction between carbon nanoparticles was found to correlate well with the number of hydration water molecules displaced upon particle aggregation, which, relative to the amount of direct nanoparticle-nanoparticle contact engendered upon aggregation, decreases with decreasing surface curvature.
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Affiliation(s)
- Liwei Li
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA
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Li L, Bedrov D, Smith GD. A molecular-dynamics simulation study of solvent-induced repulsion between C60 fullerenes in water. J Chem Phys 2005; 123:204504. [PMID: 16351278 DOI: 10.1063/1.2121647] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular-dynamics simulations of a single C(60) fullerene and pairs of C(60) fullerenes in aqueous solution have been performed for the purpose of obtaining improved understanding of the nature of solvent-induced interactions between C(60) fullerenes in water. Our simulations reveal repulsive solvent-induced interactions between two C(60) fullerenes in aqueous solution in contrast to the associative effects observed for conventional nonpolar solutes. A decomposition of the solvent-induced potential of mean force between fullerenes into entropy and energy (enthalpy) contributions reveals that the water-induced repulsion between fullerenes is energetic in origin, contrasting strongly to entropy-driven association observed for conventional nonpolar solutes. The dominance of energy in the solvent-induced interactions between C(60) fullerenes arises primarily from the high atomic density of the C(60) molecule, resulting in strong C(60)-water van der Waals attraction that is reduced upon association of the fullerenes. The water-induced repulsion is found to decrease with increasing temperature due largely to an increasing contribution from a relatively weak entropy-driven association.
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Affiliation(s)
- Liwei Li
- Department of Materials Science and Engineering and Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112, USA
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47
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Bedrov D, Smith GD, Li L. Molecular dynamics simulation study of the role of evenly spaced poly(ethylene oxide) tethers on the aggregation of C60 fullerenes in water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:5251-5. [PMID: 15924445 DOI: 10.1021/la0504816] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The aggregation behavior of C60 fullerenes and C60 fullerenes with six symmetrically tethered poly(ethylene oxide) oligomers [(PEO)-6-C60] in aqueous solutions has been studied using implicit solvent molecular dynamics simulations. Our simulations reveal that while the attraction between two (PEO)-6-C60 fullerenes in aqueous solution is stronger and longer range than that between two bare C60 fullerenes, the (PEO)-6-C60 fullerenes do not phase-separate in water but rather aggregate in chain-like clusters at concentrations where unmodified fullerenes completely phase-separate.
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