1
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Rodriguez C, Torres-Costa V, Bittner A, Morin S, Cascajo Castresana M, Chiriaev S, Modin E, Chuvilin A, Manso Silván M. Electron microscopy approach to the wetting dynamics of single organosilanized mesopores. iScience 2023; 26:107981. [PMID: 37860771 PMCID: PMC10583112 DOI: 10.1016/j.isci.2023.107981] [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: 12/30/2022] [Revised: 09/08/2023] [Accepted: 09/16/2023] [Indexed: 10/21/2023] Open
Abstract
Columnar mesoporous silicon (PSi) with hydrophobic vs. hydrophilic chemistries was chosen as a model for the local (pore-by-pore) study of water-pore interactions. Tomographic reconstructions provided a 3D view of the ramified pore structure. An in situ study of PSi wetting was conducted for categorized pore diameters by environmental scanning TEM. An appropriate setting of the contrast allows for the normalization of the gray scale in the images as a function of relative humidity (RH). This allows constructing an isotherm for each single pore and a subsequent averaging provides an isotherm for each pore size range. The isotherms systematically point to an initial adsorption through the formation of water adlayers, followed by a capillary filling process at higher RH. The local isotherms correlate with (global) gravimetric determination of wetting. Our results point at the validation of a technique for the study of aging and stability of single-pore nanoscale devices.
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Affiliation(s)
- C. Rodriguez
- Departamento de Física Aplicada, Centro de Microanálisis de Materiales and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Mecwins, Roda de Poniente 15, Tres Cantos, Madrid 28760, Spain
| | - V. Torres-Costa
- Departamento de Física Aplicada, Centro de Microanálisis de Materiales and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - A.M. Bittner
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - S. Morin
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Department of Chemistry, York University, 4700 Keele Street, Toronto M3J 1P3, Canada
| | - M. Cascajo Castresana
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Tecnalia, 20009 Donostia-San Sebastián, Spain
| | - S. Chiriaev
- Mads Clausen Institute, University of Southern Denmark, 6400 Sønderborg, Denmark
| | - E. Modin
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
| | - A. Chuvilin
- CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - M. Manso Silván
- Departamento de Física Aplicada, Centro de Microanálisis de Materiales and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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2
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Jiao S, Rivera Mirabal DM, DeStefano AJ, Segalman RA, Han S, Shell MS. Sequence Modulates Polypeptoid Hydration Water Structure and Dynamics. Biomacromolecules 2022; 23:1745-1756. [PMID: 35274944 DOI: 10.1021/acs.biomac.1c01687] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We use molecular dynamics simulations to investigate the effect of polypeptoid sequence on the structure and dynamics of its hydration waters. Polypeptoids provide an excellent platform to study small-molecule hydration in disordered polymers, as they can be precisely synthesized with a variety of sidechain chemistries. We examine water behavior near a set of peptoid oligomers in which the number and placement of nonpolar versus polar sidechains are systematically varied. To do this, we leverage a new computational workflow enabling accurate sampling of polypeptoid conformations. We find that the hydration waters are less dense, are more tetrahedral, and have slower dynamics compared to bulk water. The magnitude of these shifts increases with the number of nonpolar groups. We also find that shifts in the water structure and dynamics are strongly correlated, suggesting that experimental insight into the dynamics of hydration water obtained by Overhauser dynamic nuclear polarization (ODNP) also contains information about water structural properties. We then demonstrate the ability of ODNP to probe site-specific dynamics of hydration water near these model peptoid systems.
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Affiliation(s)
- Sally Jiao
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Daniela M Rivera Mirabal
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States.,Department of Chemical Engineering, University of Puerto Rico, Mayagüez, Puerto Rico 00681, United States
| | - Audra J DeStefano
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Rachel A Segalman
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States.,Department of Materials, University of California, Santa Barbara, California 93106, United States
| | - Songi Han
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - M Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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3
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Ranathunga DTS, Shamir A, Dai X, Nielsen SO. Molecular Dynamics Simulations of Water Condensation on Surfaces with Tunable Wettability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7383-7391. [PMID: 32498521 DOI: 10.1021/acs.langmuir.0c00915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water condensation plays a major role in a wide range of industrial applications. Over the past few years, many studies have shown interest in designing surfaces with enhanced water condensation and removal properties. It is well known that heterogeneous nucleation outperforms homogeneous nucleation in the condensation process. Because heterogeneous nucleation initiates on a surface at a small scale, it is highly desirable to characterize water-surface interactions at the molecular level. Molecular dynamics (MD) simulations can provide direct insight into heterogeneous nucleation and advance surface designs. Existing MD simulations of water condensation on surfaces were conducted by tuning the solid-water van der Waals interaction energy as a substitute for modeling surfaces with different wettabilities. However, this approach cannot reflect the real intermolecular interactions between the surface and water molecules. Here, we report MD simulations of water condensation on realistic surfaces of alkanethiol self-assembled monolayers with different head group chemistries. We show that decreasing surface hydrophobicity significantly increases the electrostatic forces between water molecules and the surface, thus increasing the water condensation rate. We observe a strong correlation between our rate of condensation results and the results from other surface characterization metrics, such as the interfacial thermal conductance, contact angle, and the molecular-scale wettability metric of Garde and co-workers. This work provides insight into the water condensation process at the molecular scale on surfaces with tunable wettability.
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Affiliation(s)
- Dineli T S Ranathunga
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Alexandra Shamir
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Xianming Dai
- Department of Mechanical Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
| | - Steven O Nielsen
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
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4
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Dai X, Sun N, Nielsen SO, Stogin BB, Wang J, Yang S, Wong TS. Hydrophilic directional slippery rough surfaces for water harvesting. SCIENCE ADVANCES 2018; 4:eaaq0919. [PMID: 29670942 PMCID: PMC5903897 DOI: 10.1126/sciadv.aaq0919] [Citation(s) in RCA: 203] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/12/2018] [Indexed: 05/21/2023]
Abstract
Multifunctional surfaces that are favorable for both droplet nucleation and removal are highly desirable for water harvesting applications but are rare. Inspired by the unique functions of pitcher plants and rice leaves, we present a hydrophilic directional slippery rough surface (SRS) that is capable of rapidly nucleating and removing water droplets. Our surfaces consist of nanotextured directional microgrooves in which the nanotextures alone are infused with hydrophilic liquid lubricant. We have shown through molecular dynamics simulations that the physical origin of the efficient droplet nucleation is attributed to the hydrophilic surface functional groups, whereas the rapid droplet removal is due to the significantly reduced droplet pinning of the directional surface structures and slippery interface. We have further demonstrated that the SRS, owing to its large surface area, hydrophilic slippery interface, and directional liquid repellency, outperforms conventional liquid-repellent surfaces in water harvesting applications.
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Affiliation(s)
- Xianming Dai
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
- Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
- Corresponding author. (X.D.); (T.-S.W.)
| | - Nan Sun
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Steven O. Nielsen
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Birgitt Boschitsch Stogin
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Jing Wang
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Shikuan Yang
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Tak-Sing Wong
- Department of Mechanical and Nuclear Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
- Corresponding author. (X.D.); (T.-S.W.)
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5
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Zhang Z, Ahn Y, Jang J. Molecular dynamics simulations of nanoscale engravings on an alkanethiol monolayer. RSC Adv 2017. [DOI: 10.1039/c7ra06005j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Thermal stability of nanoscale engravings on alkanethiol monolayer.
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Affiliation(s)
- Zhengqing Zhang
- Department of Nanoenergy Engineering
- Pusan National University
- Busan 609-735
- South Korea
| | - Yoonho Ahn
- Department of Applied Physics
- Kyung Hee University
- Yongin 446-701
- South Korea
| | - Joonkyung Jang
- Department of Nanoenergy Engineering
- Pusan National University
- Busan 609-735
- South Korea
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6
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Velachi V, Bhandary D, Singh JK, Cordeiro MNDS. Striped gold nanoparticles: New insights from molecular dynamics simulations. J Chem Phys 2016; 144:244710. [DOI: 10.1063/1.4954980] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Vasumathi Velachi
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, University of Porto, 4169-007 Porto, Portugal
| | - Debdip Bhandary
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Jayant K. Singh
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - M. Natália D. S. Cordeiro
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, University of Porto, 4169-007 Porto, Portugal
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7
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Laaksonen A, Malila J, Nenes A, Hung HM, Chen JP. Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol. Sci Rep 2016; 6:25504. [PMID: 27138171 PMCID: PMC4853788 DOI: 10.1038/srep25504] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 04/15/2016] [Indexed: 11/12/2022] Open
Abstract
Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.
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Affiliation(s)
- Ari Laaksonen
- Finnish Meteorological Institute, 00101 Helsinki, Finland
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Jussi Malila
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Athanasios Nenes
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Institute for Environmental Research & Sustainable Development, National Observatory of Athens (NOA), I. Metaxa & Vas. Pavlou, 15236 Palea Penteli, Greece
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Stadiou Str., Platani, GR-26504 Patras, Greece
| | - Hui-Ming Hung
- Department of Atmospheric Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Jen-Ping Chen
- Department of Atmospheric Sciences, National Taiwan University, Taipei 10617, Taiwan
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8
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Lin W, Clark AJ, Paesani F. Effects of surface pressure on the properties of Langmuir monolayers and interfacial water at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2147-2156. [PMID: 25642579 DOI: 10.1021/la504603s] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effects of surface pressure on the physical properties of Langmuir monolayers of palmitic acid (PA) and dipalmitoylphosphatidic acid (DPPA) at the air/water interface are investigated through molecular dynamics simulations with atomistic force fields. The structure and dynamics of both monolayers and interfacial water are compared across the range of surface pressures at which stable monolayers can form. For PA monolayers at T = 300 K, the untilted condensed phase with a hexagonal lattice structure is found at high surface pressure, while the uniformly tilted condensed phase with a centered rectangular lattice structure is observed at low surface pressure, in agreement with the available experimental data. A state with uniform chain tilt but no periodic spatial ordering is observed for DPPA monolayers on a Na(+)/water subphase at both high and low surface pressures. The hydrophobic acyl chains of both monolayers pack efficiently at all surface pressures, resulting in a very small number of gauche defects. The analysis of the hydrogen-bonding structure/dynamics at the monolayer/water interface indicates that water molecules hydrogen-bonded to the DPPA head groups reorient more slowly than those hydrogen-bonded to the PA head groups, with the orientational dynamics becoming significantly slower at high surface pressure. Possible implications for physicochemical processes taking place on marine aerosols in the atmosphere are discussed.
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Affiliation(s)
- Wei Lin
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States
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9
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Zhang J, Zhong J, Li W, Wang M, Liu B, Li Z, Yan Y. Molecular insight into the dynamical adsorption behavior of nanoscale water droplets on a heterogeneous surface. RSC Adv 2015. [DOI: 10.1039/c5ra09296e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A heterogeneous surface is constructed by adding one hydrophilic patch at the center of a hydrophobic surface, and the dynamical adsorption process of nanoscale water droplets is investigated adopting molecular dynamics simulations.
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Affiliation(s)
- Jun Zhang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Jie Zhong
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Wen Li
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Muhan Wang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Bing Liu
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Zhen Li
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Youguo Yan
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People’s Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
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10
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Zhang J, Li W, Yan Y, Wang Y, Liu B, Shen Y, Chen H, Liu L. Molecular insight into nanoscale water films dewetting on modified silica surfaces. Phys Chem Chem Phys 2015; 17:451-8. [DOI: 10.1039/c4cp04554h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this work, molecular dynamics simulations are adopted to investigate the microscopic dewetting mechanism of nanoscale water films on methylated silica surfaces.
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Affiliation(s)
- Jun Zhang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Wen Li
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Youguo Yan
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Yefei Wang
- School of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
| | - Bing Liu
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Yue Shen
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Haixiang Chen
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Liang Liu
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
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11
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Driskill J, Vanzo D, Bratko D, Luzar A. Wetting transparency of graphene in water. J Chem Phys 2014; 141:18C517. [DOI: 10.1063/1.4895541] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Joshua Driskill
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
| | - Davide Vanzo
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
| | - Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
| | - Alenka Luzar
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-2006, USA
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12
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Vasumathi V, Cordeiro MND. Molecular dynamics study of mixed alkanethiols covering a gold surface at three different arrangements. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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13
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Yiapanis G, Christofferson AJ, Plazzer M, Weir MP, Prime EL, Qiao GG, Solomon DH, Yarovsky I. Molecular mechanism of stabilization of thin films for improved water evaporation protection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14451-9. [PMID: 24215111 DOI: 10.1021/la402275p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
All-atom molecular dynamics simulations and experimental characterization have been used to examine the structure and dynamics of novel evaporation-suppressing films where the addition of a water-soluble polymer to an ethylene glycol monooctadecyl ether monolayer leads to improved water evaporation resistance. Simulations and Langmuir trough experiments demonstrate the surface activity of poly(vinyl pyrrolidone) (PVP). Subsequent MD simulations performed on the thin films supported by the PVP sublayer show that, at low surface pressures, the polymer tends to concentrate at the film/water interface. The simulated atomic concentration profiles, hydrogen bonding patterns, and mobility analyses of the water-polymer-monolayer interfaces reveal that the presence of PVP increases the atomic density near the monolayer film, improves the film stability, and reduces the mobility of interfacial waters. These observations explain the molecular basis of the improved efficacy of these monolayer/polymer systems for evaporation protection of water and can be used to guide future development of organic thin films for other applications.
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Affiliation(s)
- George Yiapanis
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University , GPO Box 2476, Victoria, 3001, Australia
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14
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Li E, Du Z, Yuan S. Properties of a water layer on hydrophilic and hydrophobic self-assembled monolayer surfaces: A molecular dynamics study. Sci China Chem 2013. [DOI: 10.1007/s11426-013-4835-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Darvas M, Picaud S, Jedlovszky P. Molecular dynamics simulations of the water adsorption around malonic acid aerosol models. Phys Chem Chem Phys 2013; 15:10942-51. [DOI: 10.1039/c3cp50608h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Pertsin A, Grunze M. Computer simulation of adhesion between hydrophilic and hydrophobic self-assembled monolayers in water. J Chem Phys 2012; 137:054701. [PMID: 22894365 DOI: 10.1063/1.4739745] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The grand canonical Monte Carlo technique and atomistic force fields are used to calculate the force-distance relations and free energies of adhesion between carboxyl and methyl terminated alkanethiolate self-assembled monolayers (SAMs) in water. Both symmetric and asymmetric confinements are considered, as formed by like and unlike SAMs, respectively. As the confinement is increased, water confined by the hydrophobic methyl terminated SAMs experiences capillary evaporation. As a consequence, the adhesion energy is determined by the direct interaction between bare SAMs. In the asymmetric system, an incomplete capillary evaporation is observed, with the number of water molecules dropped by more than an order of magnitude. The remaining water molecules are all adsorbed on the hydrophilic SAM, while the hydrophobic SAM is separated from the rest of the system by a thin vapor layer. The calculated free energies of adhesion are in acceptable agreement with experiment.
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Affiliation(s)
- Alexander Pertsin
- Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
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17
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Wang S, Tu Y, Wan R, Fang H. Evaporation of Tiny Water Aggregation on Solid Surfaces with Different Wetting Properties. J Phys Chem B 2012; 116:13863-7. [DOI: 10.1021/jp302142s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Shen Wang
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
- Graduate School of the Chinese Academy of Sciences, Beijing 100080,
China
| | - Yusong Tu
- Institute of Systems
Biology, Shanghai University, Shanghai,
200444, China
| | - Rongzheng Wan
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
| | - Haiping Fang
- Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai, 201800, China
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18
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Tu A, Kwag HR, Barnette AL, Kim SH. Water adsorption isotherms on CH3-, OH-, and COOH-terminated organic surfaces at ambient conditions measured with PM-RAIRS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15263-9. [PMID: 23075312 DOI: 10.1021/la302848k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The water adsorption isotherms on methyl (CH(3))-, hydroxyl (OH)-, and carboxylic acid (COOH)-terminated alkylthiol self-assembled monolayers (SAMs) on Au were studied at room temperature and ambient pressure with polarization modulation reflection-absorption infrared spectroscopy (PM-RAIRS). PM-RAIRS analysis showed that water does not adsorb at all on the CH(3)-SAM/Au at subsaturation humidity conditions. In a dry Ar environment, the OH-SAM/Au holds at least 2 layer thick strongly bound water molecules which exhibit a broad O-H stretch vibration peak centered at ∼3360 cm(-1). The peak position implies that the strongly bound water layer on the OH SAM is more like a liquid than an ice. The additional uptake of water in humid environments is relatively weak, and the peak position changes very little. Unlike the OH-SAM/Au, the COOH-SAM/Au does not have strongly bound water layer. This seems to be due to the strong hydrogen bonding between terminal COOH groups in dry conditions. The weak interactions between water and carboxyl groups at low relative humidity (RH) and the solvation of dissociated carboxylic groups in high RH lead to a type III isotherm behavior, based on the BET categories, for water adsorption on the COOH-SAM/Au. The water spectra on the COOH-SAM at RH > 45% are centered at ∼3430 cm(-1) and very broad, indicating that the hydrogen-bonding network of water on the COOH-SAM is much different from that on the OH-SAM.
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Affiliation(s)
- Aimee Tu
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Zhao J, Wang Q, Liang G, Zheng J. Molecular dynamics simulations of low-ordered alzheimer β-amyloid oligomers from dimer to hexamer on self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14876-14887. [PMID: 22077332 DOI: 10.1021/la2027913] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Accumulation of small soluble oligomers of amyloid-β (Aβ) in the human brain is thought to play an important pathological role in Alzheimer's disease. The interaction of these Aβ oligomers with cell membrane and other artificial surfaces is important for the understanding of Aβ aggregation and toxicity mechanisms. Here, we present a series of exploratory molecular dynamics (MD) simulations to study the early adsorption and conformational change of Aβ oligomers from dimer to hexamer on three different self-assembled monolayers (SAMs) terminated with CH(3), OH, and COOH groups. Within the time scale of MD simulations, the conformation, orientation, and adsorption of Aβ oligomers on the SAMs is determined by complex interplay among the size of Aβ oligomers, the surface chemistry of the SAMs, and the structure and dynamics of interfacial waters. Energetic analysis of Aβ adsorption on the SAMs reveals that Aβ adsorption on the SAMs is a net outcome of different competitions between dominant hydrophobic Aβ-CH(3)-SAM interactions and weak CH(3)-SAM-water interactions, between dominant electrostatic Aβ-COOH-SAM interactions and strong COOH-SAM-water interactions, and between comparable hydrophobic and electrostatic Aβ-OH-SAM interactions and strong OH-SAM-water interactions. Atomic force microscopy images also confirm that all of three SAMs can induce the adsorption and polymerization of Aβ oligomers. Structural analysis of Aβ oligomers on the SAMs shows a dramatic increase in structural stability and β-sheet content from dimer to trimer, suggesting that Aβ trimer could act as seeds for Aβ polymerization on the SAMs. This work provides atomic-level understanding of Aβ peptides at interface.
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Affiliation(s)
- Jun Zhao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA
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James M, Ciampi S, Darwish TA, Hanley TL, Sylvester SO, Gooding JJ. Nanoscale water condensation on click-functionalized self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10753-10762. [PMID: 21780835 DOI: 10.1021/la202359c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have examined the nanoscale adsorption of molecular water under ambient conditions onto a series of well-characterized functionalized surfaces produced by Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC or "click") reactions on alkyne-terminated self-assembled monolayers on silicon. Water contact angle (CA) measurements reveal a range of macroscopic hydrophilicity that does not correlate with the tendency of these surfaces to adsorb water at the molecular level. X-ray reflectometry has been used to follow the kinetics of water adsorption on these "click"-functionalized surfaces, and also shows that dense continuous molecular water layers are formed over 30 h. For example, a highly hydrophilic surface, functionalized by an oligo(ethylene glycol) moiety (with a CA = 34°) showed 2.9 Å of adsorbed water after 30 h, while the almost hydrophobic underlying alkyne-terminated monolayer (CA = 84°) showed 5.6 Å of adsorbed water over the same period. While this study highlights the capacity of X-ray reflectometry to study the structure of adsorbed water on these surfaces, it should also serve as a warning for those intending to characterize self-assembled monolayers and functionalized surfaces to avoid contamination by even trace amounts of water vapor. Moreover, contact angle measurements alone cannot be relied upon to predict the likely degree of moisture uptake on such surfaces.
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Affiliation(s)
- Michael James
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC NSW 2232, Australia.
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Xu Z, Song K, Yuan SL, Liu CB. Microscopic wetting of self-assembled monolayers with different surfaces: a combined molecular dynamics and quantum mechanics study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8611-8620. [PMID: 21639099 DOI: 10.1021/la201328y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Molecular dynamics simulations are used to study the micronature of the organization of water molecules on the flat surface of well-ordered self-assembled monolayers (SAMs) of 18-carbon alkanethiolate chains bound to a silicon (111) substrate. Six different headgroups (-CH(3), -C═C, -OCH(3), -CN, -NH(2), -COOH) are used to tune the character of the surface from hydrophobic to hydrophilic, while the level of hydration is consistent on all six SAM surfaces. Quantum mechanics calculations are employed to optimize each alkyl chain of the different SAMs with one water molecule and to investigate changes in the configuration of each headgroup under hydration. We report the changes of the structure of the six SAMs with different surfaces in the presence of water, and the area of the wetted surface of each SAM, depending on the terminal group. Our results suggest that a corrugated and hydrophobic surface will be formed if the headgroups of SAM surface are not able to form H-bonds either with water molecules or between adjacent groups. In contrast, the formation of hydrogen bonds not only among polar heads but also between polar heads and water may enhance the SAM surface hydrophilicity and corrugation. We explicitly discuss the micromechanisms for the hydration of three hydrophilic SAM (CN-, NH(2)- and COOH-terminated) surfaces, which is helpful to superhydrophilic surface design of SAM in biomimetic materials.
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Affiliation(s)
- Zhen Xu
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan, China
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Fan H, Resasco DE, Striolo A. Amphiphilic silica nanoparticles at the decane-water interface: insights from atomistic simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5264-74. [PMID: 21449581 DOI: 10.1021/la200428r] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The properties of 3 nm-diameter silica nanoparticles with different surface chemistry were systematically investigated at the decane-water interface using molecular dynamics simulations. Our results show that the decane-water interfacial tension is not much influenced by the presence of the nanoparticles. The three-phase contact angle increases with nanoparticle surface hydrophobicity. Contact angles observed for the nanoparticles at 300 and at 350 K differ very little. The contact angle of the nanoparticle with randomly dispersed hydrophobic groups is smaller than that observed in Janus nanoparticles of equal overall surface chemistry composition. The energy necessary to desorb Janus nanoparticles from the interface is usually higher than that required to desorb the corresponding homogeneous nanoparticles. Desorption from the interface into the aqueous phase is preferred over that into the organic phase for all except one of the nanoparticles considered. Structural and dynamic properties including nanoparticle rotational relaxation, solvent density profiles, and solvent residence autocorrelation functions near the nanoparticles are also presented. The data are useful for designing Pickering emulsions.
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Affiliation(s)
- Heng Fan
- School of Chemical, Biological, and Materials Engineering, The University of Oklahoma, Norman, Oklahoma 73019, United States
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Probing surface tension additivity on chemically heterogeneous surfaces by a molecular approach. Proc Natl Acad Sci U S A 2011; 108:6374-9. [PMID: 21460249 DOI: 10.1073/pnas.1014970108] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Surface free energy of a chemically heterogeneous surface is often treated as an approximately additive quantity through the Cassie equation [Cassie ABD (1948) Discuss Faraday Soc 3:11-16]. However, deviations from additivity are common, and molecular interpretations are still lacking. We use molecular simulations to measure the microscopic analogue of contact angle, Θ(c), of aqueous nanodrops on heterogeneous synthetic and natural surfaces as a function of surface composition. The synthetic surfaces are layers of graphene functionalized with prototypical nonpolar and polar head group: methyl, amino, and nitrile. We demonstrate positive as well as negative deviations from the linear additivity. We show the deviations reflect the uneven exposure of mixture components to the solvent and the linear relation is recovered if fractions of solvent-accessible surface are used as the measure of composition. As the spatial variations in polarity become of larger amplitude, the linear relation can no longer be obtained. Protein surfaces represent such natural patterned surfaces, also characterized by larger patches and roughness. Our calculations reveal strong deviations from linear additivity on a prototypical surface comprising surface fragments of melittin dimer. The deviations reflect the disproportionately strong influence of isolated polar patches, preferential wetting, and changes in the position of the liquid interface above hydrophobic patches. Because solvent-induced contribution to the free energy of surface association grows as cos Θ(c), deviations of cos Θ(c) from the linear relation directly reflect nonadditive adhesive energies of biosurfaces.
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Knopf DA, Forrester SM, Slade JH. Heterogeneous oxidation kinetics of organic biomass burning aerosol surrogates by O3, NO2, N2O5, and NO3. Phys Chem Chem Phys 2011; 13:21050-62. [DOI: 10.1039/c1cp22478f] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Moussa SG, Finlayson-Pitts BJ. Reaction of gas phase OH with unsaturated self-assembled monolayers and relevance to atmospheric organic oxidations. Phys Chem Chem Phys 2010; 12:9419-28. [PMID: 20532334 DOI: 10.1039/c000447b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The kinetics and mechanisms of the reaction of gas phase OH radicals with organics on surfaces are of fundamental chemical interest, as well as relevant to understanding the degradation of organics on tropospheric surfaces or when they are components of airborne particles. We report here studies of the oxidation of a terminal alkene self-assembled monolayer (7-octenyltrichlorosilane, C8= SAM) on a germanium attenuated total reflectance crystal by OH radicals at a concentration of 2.1 x 10(5) cm(-3) at 1 atm total pressure and 298 K in air. Loss of the reactant SAM and the formation of surface products were followed in real time using infrared spectroscopy. From the rate of loss of the C=C bond, a reaction probability within experimental error of unity was derived. The products formed on the surface include organic nitrates and carbonyl compounds, with yields of 10 +/- 4% and < or = 7 +/- 4%, respectively, and there is evidence for the formation of organic products with C-O bonds such as alcohols, ethers and/or alkyl peroxides and possibly peroxynitrates. The yield of organic nitrates relative to carbonyl compounds is higher than expected based on analogous gas phase mechanisms, suggesting that the branching ratio for the RO(2) + NO reaction is shifted to favor the formation of organic nitrates when the reaction occurs on a surface. Water uptake onto the surface was only slightly enhanced upon oxidation, suggesting that oxidation per se cannot be taken as a predictor of increased hydrophilicity of atmospheric organics. These experiments indicate that the mechanisms for the surface reactions are different from gas phase reactions, but the OH oxidation of surface species will still be a significant contributor to determining their lifetimes in air.
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Affiliation(s)
- Samar G Moussa
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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Szőri M, Jedlovszky P, Roeselová M. Water adsorption on hydrophilic and hydrophobic self-assembled monolayers as proxies for atmospheric surfaces. A grand canonical Monte Carlo simulation study. Phys Chem Chem Phys 2010; 12:4604-16. [DOI: 10.1039/b923382b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Paranthaman S, Coudert FX, Fuchs AH. Water adsorption in hydrophobic MOF channels. Phys Chem Chem Phys 2010; 12:8123-9. [DOI: 10.1039/b925074c] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Finlayson-Pitts BJ. Reactions at surfaces in the atmosphere: integration of experiments and theory as necessary (but not necessarily sufficient) for predicting the physical chemistry of aerosols. Phys Chem Chem Phys 2009; 11:7760-79. [DOI: 10.1039/b906540g] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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