1
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Arvelo D, Comer J, Schmit J, Garcia R. Interfacial Water Is Separated from a Hydrophobic Silica Surface by a Gap of 1.2 nm. ACS NANO 2024; 18:18683-18692. [PMID: 38973716 PMCID: PMC11256893 DOI: 10.1021/acsnano.4c05689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/26/2024] [Accepted: 06/27/2024] [Indexed: 07/09/2024]
Abstract
The interaction of liquid water with hydrophobic surfaces is ubiquitous in life and technology. Yet, the molecular structure of interfacial liquid water on these surfaces is not known. By using a 3D atomic force microscope, we characterize with angstrom resolution the structure of interfacial liquid water on hydrophobic and hydrophilic silica surfaces. The combination of 3D AFM images and molecular dynamics simulations reveals that next to a hydrophobic silica surface, there is a 1.2 nm region characterized by a very low density of water. In contrast, the 3D AFM images obtained of a hydrophilic silica surface reveal the presence of hydration layers next to the surface. The gap observed on hydrophobic silica surfaces is filled with two-to-three layers of straight-chain alkanes. We developed a 2D Ising model that explains the formation of a continuous hydrocarbon layer on hydrophobic silica surfaces.
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Affiliation(s)
- Diana
M. Arvelo
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
| | - Jeffrey Comer
- Department
of Anatomy and Physiology, Kansas State
University, Manhattan, Kansas 66506, United States
| | - Jeremy Schmit
- Department
of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Ricardo Garcia
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Madrid 28049, Spain
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2
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Memon H, Wang J, Hou X. Interdependence of Surface Roughness on Icephobic Performance: A Review. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4607. [PMID: 37444925 DOI: 10.3390/ma16134607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023]
Abstract
Ice protection techniques have attracted significant interest, notably in aerospace and wind energy applications. However, the current solutions are mostly costly and inconvenient due to energy-intensive and environmental concerns. One of the appealing strategies is the use of passive icephobicity, in the form of coatings, which is induced by means of several material strategies, such as hydrophobicity, surface texturing, surface elasticity, and the physical infusion of ice-depressing liquids, etc. In this review, surface-roughness-related icephobicity is critically discussed to understand the challenges and the role of roughness, especially on superhydrophobic surfaces. Surface roughness as an intrinsic, independent surface property for anti-icing and de-icing performance is also debated, and their interdependence is explained using the related physical mechanisms and thermodynamics of ice nucleation. Furthermore, the role of surface roughness in the case of elastomeric or low-modulus polymeric coatings, which typically instigate an easy release of ice, is examined. In addition to material-centric approaches, the influence of surface roughness in de-icing evaluation is also explored, and a comparative assessment is conducted to understand the testing sensitivity to various surface characteristics. This review exemplifies that surface roughness plays a crucial role in incorporating and maintaining icephobic performance and is intrinsically interlinked with other surface-induced icephobicity strategies, including superhydrophobicity and elastomeric surfaces. Furthermore, the de-icing evaluation methods also appear to be roughness sensitive in a certain range, indicating a dominant role of mechanically interlocked ice.
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Affiliation(s)
- Halar Memon
- Faculty of Engineering, University of Nottingham, University Park Campus, Nottingham NG7 2RD, UK
| | - Jie Wang
- School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Xianghui Hou
- State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials, Northwestern Polytechnical University, Xi'an 710072, China
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3
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Mossayebi Z, Jafari VF, Gurr PA, Simons R, Qiao GG. Reduced Ice Adhesion Using Amphiphilic Poly(Ionic Liquid)-Based Surfaces. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7454-7465. [PMID: 36708328 DOI: 10.1021/acsami.2c21500] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Ice build-up on solid surfaces causes significant economic losses for a range of industries. One solution to this problem is the development of coatings with low ice adhesion strength. Amphiphilic poly(ionic liquid) (PIL)-based surfaces have been recently reported for antifogging/antifrosting applications. However, they have possible anti-icing properties through lowering the ice adhesion strength that have yet to be reported. Herein, we designed well-defined triblock copolymers composed of a polydimethylsiloxane component coupled with PIL segments of poly([2 (methacryloyloxy)ethyl] trimethylammonium chloride) (PMETAC), which were subsequently UV-cured with an oligo(ethylene glycol) dimethacrylate (OEGDMA) cross-linker. The structure-property relationships of the resultant semi-interpenetrating polymer networks (SIPNs) were investigated by varying the counterion (i.e., trimethylammonium bis(trifluoromethanesulfonyl)imide (TFSI-)) and the content of the PIL segments and cross-linker. An ice adhesion strength as low as 13.3 ± 8.6 kPa was observed for the coating containing 12.5 wt % of PMETAC segment and 5 wt % of OEGDMA, which is one of the lowest values reported so far for the amphiphilic coatings. Characterization of the coatings in terms of surface features, wettability, and hydration states have enabled the elucidation of different deicing mechanisms. Self-lubrication due to the existence of nonfreezable bound water led to the obtained low ice adhesion strength. This work offers a new approach for the exploration of PIL-based icephobic coatings for practical applications.
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Affiliation(s)
- Zahra Mossayebi
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
- CSIRO Manufacturing, Melbourne, Victoria 3169, Australia
| | - Vianna F Jafari
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gurr
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Ranya Simons
- CSIRO Manufacturing, Melbourne, Victoria 3169, Australia
| | - Greg G Qiao
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
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4
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Coe MK, Evans R, Wilding NB. Understanding the physics of hydrophobic solvation. J Chem Phys 2023; 158:034508. [PMID: 36681639 DOI: 10.1063/5.0134060] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Simulations of water near extended hydrophobic spherical solutes have revealed the presence of a region of depleted density and accompanying enhanced density fluctuations. The physical origin of both phenomena has remained somewhat obscure. We investigate these effects employing a mesoscopic binding potential analysis, classical density functional theory (DFT) calculations for a simple Lennard-Jones solvent, and Grand Canonical Monte Carlo (GCMC) simulations of a monatomic water (mw) model. We argue that the density depletion and enhanced fluctuations are near-critical phenomena. Specifically, we show that they can be viewed as remnants of the critical drying surface phase transition that occurs at bulk liquid-vapor coexistence in the macroscopic planar limit, i.e., as the solute radius Rs → ∞. Focusing on the radial density profile ρ(r) and a sensitive spatial measure of fluctuations, the local compressibility profile χ(r), our binding potential analysis provides explicit predictions for the manner in which the key features of ρ(r) and χ(r) scale with Rs, the strength of solute-water attraction ɛsf, and the deviation from liquid-vapor coexistence of the chemical potential, δμ. These scaling predictions are confirmed by our DFT calculations and GCMC simulations. As such, our theory provides a firm basis for understanding the physics of hydrophobic solvation.
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Affiliation(s)
- Mary K Coe
- H. H. Wills Physics Laboratory, Royal Fort, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Robert Evans
- H. H. Wills Physics Laboratory, Royal Fort, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Nigel B Wilding
- H. H. Wills Physics Laboratory, Royal Fort, University of Bristol, Bristol BS8 1TL, United Kingdom
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5
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Belotti M, El‐Tahawy MMT, Yu L, Russell IC, Darwish N, Coote ML, Garavelli M, Ciampi S. Luciferase-free Luciferin Electrochemiluminescence. Angew Chem Int Ed Engl 2022; 61:e202209670. [PMID: 36169114 PMCID: PMC9828091 DOI: 10.1002/anie.202209670] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Indexed: 01/12/2023]
Abstract
Luciferin is one of Nature's most widespread luminophores, and enzymes that catalyze luciferin luminescence are the basis of successful commercial "glow" assays for gene expression and metabolic ATP formation. Herein we report an electrochemical method to promote firefly's luciferin luminescence in the absence of its natural biocatalyst-luciferase. We have gained experimental and computational insights on the mechanism of the enzyme-free luciferin electrochemiluminescence, demonstrated its spectral tuning from green to red by means of electrolyte engineering, proven that the colour change does not require, as still debated, a keto/enol isomerization of the light emitter, and gained evidence of the electrostatic-assisted stabilization of the charge-transfer excited state by double layer electric fields. Luciferin's electrochemiluminescence, as well as the in situ generation of fluorescent oxyluciferin, are applied towards an optical measurement of diffusion coefficients.
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Affiliation(s)
- Mattia Belotti
- School of Molecular and Life SciencesCurtin UniversityBentley6102Western AustraliaAustralia
| | - Mohsen M. T. El‐Tahawy
- Dipartimento di Chimica Industriale “Toso Montanari”Università di BolognaBologna40136Emilia RomagnaItaly
- Chemistry DepartmentFaculty of ScienceDamanhour UniversityDamanhour22511Egypt
| | - Li‐Juan Yu
- Research School of ChemistryAustralian National UniversityCanberra2601Australian Capital TerritoryAustralia
| | - Isabella C. Russell
- Research School of ChemistryAustralian National UniversityCanberra2601Australian Capital TerritoryAustralia
| | - Nadim Darwish
- School of Molecular and Life SciencesCurtin UniversityBentley6102Western AustraliaAustralia
| | - Michelle L. Coote
- Institute for Nanoscale Science and TechnologyCollege of Science and EngineeringFlinders UniversityBedford Park5042South AustraliaAustralia
| | - Marco Garavelli
- Dipartimento di Chimica Industriale “Toso Montanari”Università di BolognaBologna40136Emilia RomagnaItaly
| | - Simone Ciampi
- School of Molecular and Life SciencesCurtin UniversityBentley6102Western AustraliaAustralia
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6
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Pardehkhorram R, Andrieu-Brunsen A. Pushing the limits of nanopore transport performance by polymer functionalization. Chem Commun (Camb) 2022; 58:5188-5204. [PMID: 35394003 DOI: 10.1039/d2cc01164f] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Inspired by the design and performance of biological pores, polymer functionalization of nanopores has emerged as an evolving field to advance transport performance within the last few years. This feature article outlines developments in nanopore functionalization and the resulting transport performance including gating based on electrostatic interaction, wettability and ligand binding, gradual transport controlled by polymerization as well as functionalization-based asymmetric nanopore and nanoporous material design going towards the transport direction. Pushing the limits of nanopore transport performance and thus reducing the performance gap between biological and technological pores is strongly related to advances in polymerization chemistry and their translation into nanopore functionalization. Thereby, the effect of the spatial confinement has to be considered for polymer functionalization as well as for transport regulation, and mechanistic understanding is strongly increased by combining experiment and theory. A full mechanistic understanding together with highly precise nanopore structure design and polymer functionalization is not only expected to improve existing application of nanoporous materials but also opens the door to new technologies. The latter might include out of equilibrium devices, ionic circuits, or machine learning based sensors.
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Affiliation(s)
- Raheleh Pardehkhorram
- Macromolecular Chemistry, Smart Membranes, Technical University of Darmstadt, 64287 Darmstadt, Germany.
| | - Annette Andrieu-Brunsen
- Macromolecular Chemistry, Smart Membranes, Technical University of Darmstadt, 64287 Darmstadt, Germany.
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7
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Coe MK, Evans R, Wilding NB. Density Depletion and Enhanced Fluctuations in Water near Hydrophobic Solutes: Identifying the Underlying Physics. PHYSICAL REVIEW LETTERS 2022; 128:045501. [PMID: 35148161 DOI: 10.1103/physrevlett.128.045501] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
We investigate the origin of the density depletion and enhanced density fluctuations that occur in water in the vicinity of an extended hydrophobic solute. We argue that both phenomena are remnants of the critical drying surface phase transition that occurs at liquid-vapor coexistence in the macroscopic planar limit, i.e., as the solute radius R_{s}→∞. Focusing on the density profile ρ(r) and a sensitive spatial measure of fluctuations, the local compressibility profile χ(r), we develop a scaling theory which expresses the extent of the density depletion and enhancement in compressibility in terms of R_{s}, the strength of solute-water attraction ϵ_{s}, and the deviation from liquid-vapor coexistence δμ. Testing the predictions against results of classical density functional theory for a simple solvent and grand canonical Monte Carlo simulations of a popular water model, we find that the theory provides a firm physical basis for understanding how water behaves at a hydrophobe.
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Affiliation(s)
- Mary K Coe
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Robert Evans
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Nigel B Wilding
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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8
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Liu Y, Xia XH. Thermally Driven Transformation of Water Clustering Structures at Self-Assembled Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11493-11498. [PMID: 34549963 DOI: 10.1021/acs.langmuir.1c01724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Water clustering structures are considered to play key roles in various temperature-dependent life activities. However, our fundamental understanding of the temperature-dependent water structures remains murky because of the limits of the real-time and real-condition monitoring techniques at the molecular level. We propose an in situ ATR-IR approach combining Gaussian fitting to qualitatively and quantitatively explore the temperature-dependent structural stability and transformation of the three water components, multimer water (MW), intermediate water (IW), and network water (NW), on interfaces with different wettabilities. Our results show that the transformation between NW and IW/MW will occur with a change in temperature. This conversion process shows reversibility on hydrophilic Au NPs film/ZnSe, while it is irreversible on a hydrophobic mercaptohexane self-assembled monolayer due to the irreversibility of the monolayer structure and the hydrophobic confinement effect. The established approach enables us to explore the change in the water properties at any interfaces upon external stimuli.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
- School of Environment, Nanjing Normal University, Nanjing, Jiangsu 210023, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
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9
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Rahpeima S, Dief EM, Ciampi S, Raston CL, Darwish N. Impermeable Graphene Oxide Protects Silicon from Oxidation. ACS APPLIED MATERIALS & INTERFACES 2021; 13:38799-38807. [PMID: 34342425 DOI: 10.1021/acsami.1c06495] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The presence of a natural silicon oxide (SiOx) layer over the surface of silicon (Si) has been a roadblock for hybrid semiconductor and organic electronics technology. The presence of an insulating oxide layer is a limiting operational factor, which blocks charge transfer and therefore electrical signals for a range of applications. Etching the SiOx layer by fluoride solutions leaves a reactive Si-H surface that is only stable for few hours before it starts reoxidizing under ambient conditions. Controlled passivation of silicon is also of key importance for improving Si photovoltaic efficiency. Here, we show that a thin layer of graphene oxide (GOx) prevents Si surfaces from oxidation under ambient conditions for more than 30 days. In addition, we show that the protective GOx layer can be modified with molecules enabling a functional surface that allows for further chemical conjugation or connections with upper electrodes, while preserving the underneath Si in a nonoxidized form. The GOx layer can be switched electrochemically to reduced graphene oxide, allowing the development of a dynamic material for molecular electronics technologies. These findings demonstrate that 2D materials are alternatives to organic self-assembled monolayers that are typically used to protect and tune the properties of Si and open a realm of possibilities that combine Si and 2D materials technologies.
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Affiliation(s)
- Soraya Rahpeima
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
- Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Essam M Dief
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | - Simone Ciampi
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | - Colin L Raston
- Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
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10
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Wang D, Tian Y, Jiang L. Abnormal Properties of Low-Dimensional Confined Water. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100788. [PMID: 34176214 DOI: 10.1002/smll.202100788] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/25/2021] [Indexed: 06/13/2023]
Abstract
Water molecules confined to low-dimensional spaces exhibit unusual properties compared to bulk water. For example, the alternating hydrophilic and hydrophobic nanodomains on flat silicon wafer can induce the abnormal spreading of water (contact angles near 0°) which is caused by the 2D capillary effect. Hence, exploring the physicochemical properties of confined water from the nanoscale is of great value for understanding the challenges in material science and promoting the applications of nanomaterials in the fields of mass transport, nanofluidic designing, and fuel cell. The knowledge framework of confined water can also help to better understand the complex functions of the hydration layer of biomolecules, and even trace the origin of life. In this review, the physical properties, abnormal behaviors, and functions of the confined water are mainly summarized through several common low-dimensional water formats in the fields of solid/air-water interface, nanochannel confinement, and biological hydration layer. These researches indicate that the unusual behaviors of the confined water depend strongly on the confinement size and the interaction between the molecules and confining surface. These diverse properties of confined water open a new door to materials science and may play an important role in the future development of biology.
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Affiliation(s)
- Dianyu Wang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Ye Tian
- Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
- Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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11
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Affiliation(s)
- Tomohiro Hayashi
- Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
- JST-PRESTO (Materials Informatics), 4-1-8 Hon-cho, Kawaguchi, Saitama 332-0012, Japan
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12
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Shaat M, Javed U, Faroughi S. Wettability and confinement size effects on stability of water conveying nanotubes. Sci Rep 2020; 10:17167. [PMID: 33051583 PMCID: PMC7555514 DOI: 10.1038/s41598-020-74398-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 09/25/2020] [Indexed: 12/02/2022] Open
Abstract
This study investigates the wettability and confinement size effects on vibration and stability of water conveying nanotubes. We present an accurate assessment of nanotube stability by considering the exact mechanics of the fluid that is confined in the nanotube. Information on the stability of nanotubes in relation to the fluid viscosity, the driving force of the fluid flow, the surface wettability of the nanotube, and the nanotube size is missing in the literature. For the first time, we explore the surface wettability dependence of the nanotube natural frequencies and stability. By means of hybrid continuum-molecular mechanics (HCMM), we determined water viscosity variations inside the nanotube. Nanotubes with different surface wettability varying from super-hydrophobic to super-hydrophilic nanotubes were studied. We demonstrated a multiphase structure of nanoconfined water in nanotubes. Water was seen as vapor at the interface with the nanotube, ice shell in the middle, and liquid water in the nanotube core. The average velocity of water flow in the nanotube was obtained strongly depend on the surface wettability and the confinement size. In addition, we report the natural frequencies of the nanotube as functions of the applied pressure and the nanotube size. Mode divergence and flutter instabilities were observed, and the activation of these instabilities strongly depended on the nanotube surface wettability and size. This work gives important insights into understanding the stability of nanotubes conveying fluids depending on the operating pressures and the wettability and size of confinement. We revealed that hydrophilic nanotubes are generally more stable than hydrophobic nanotubes when conveying fluids.
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Affiliation(s)
- M Shaat
- Mechanical Engineering Department, Abu Dhabi University, P.O.BOX 1790, Al Ain, United Arab Emirates.
| | - U Javed
- Department of Engineering, American University of Iraq Sulaimani (AUIS), Sulaimania, 46001, Iraq
| | - S Faroughi
- Faculty of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
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13
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Joghee SH, Uthandi KM, Singh N, Katti S, Kumar P, Renganayagalu RK, Pullithadathil B. Evolution of Temperature-Driven Interfacial Wettability and Surface Energy Properties on Hierarchically Structured Porous Superhydrophobic Pseudoboehmite Thin Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6352-6364. [PMID: 32397715 DOI: 10.1021/acs.langmuir.0c00368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Interaction of water on heterogeneous nonwetting interfaces has fascinated researchers' attention for wider applications. Herein, we report the evolution of hierarchical micro-/nanostructures on superhydrophobic pseudoboehmite surfaces created from amorphous Al2O3 films and unraveled their temperature-driven wettability and surface energy properties. The influence of hot water immersion temperature on the dissolution-reprecipitation mechanism and the surface geometry of the Al2O3 film have been extensively analyzed, which helped in attaining the optimal Cassie-Baxter state. The evolution of pseudoboehmite films has been structurally characterized using grazing incidence X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy. Interfacial surface energy components on the structured superhydrophobic surface exhibited a very low surface energy of ∼4.6 mN/m at room temperature and ultrahigh water contact angle >175°. The interaction between water droplets on the nonwetting surface was comprehended and correlated to the temperature-dependent surface energy properties. The surface energy and wettability of the structured pseudoboehmite superhydrophobic surface exhibited an inverse behavior as a function of temperature. Interestingly, the superhydrophobic surface exhibited "Leidenfrost effect" below the boiling point of water (67 °C), which is further correlated with the intermolecular forces, interfacial water molecules and surface-terminated groups. These high-temperature wetting transition studies could be potentially valuable for solid-liquid systems working at nonambient temperatures, and also this approach can pave new pathways for better understanding of the solid/liquid interfacial interactions on nanoengineered superhydrophobic surfaces.
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Affiliation(s)
- Shalini Halan Joghee
- Nanotech Research, Innovation and Incubation Center, PSG Institute of Advanced Studies, Coimbatore 641 004, India
| | | | - Nimmi Singh
- ONGC Energy Centre, SCOPE Minar, Lakshmi Nagar, Delhi 110092, India
| | - Sanjeev Katti
- ONGC Energy Centre, SCOPE Minar, Lakshmi Nagar, Delhi 110092, India
| | - Peeyush Kumar
- ONGC Energy Centre, SCOPE Minar, Lakshmi Nagar, Delhi 110092, India
| | - Ravi Kottan Renganayagalu
- Nanotech Research, Innovation and Incubation Center, PSG Institute of Advanced Studies, Coimbatore 641 004, India
| | - Biji Pullithadathil
- Nanotech Research, Innovation and Incubation Center, PSG Institute of Advanced Studies, Coimbatore 641 004, India
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14
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Xie L, Cui X, Gong L, Chen J, Zeng H. Recent Advances in the Quantification and Modulation of Hydrophobic Interactions for Interfacial Applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2985-3003. [PMID: 32023067 DOI: 10.1021/acs.langmuir.9b03573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Hydrophobic interaction is responsible for a variety of colloidal phenomena, which also plays a key role in achieving the desired characteristics and functionalities for a wide range of interfacial applications. In this feature article, our recent advances in the quantification and modulation of hydrophobic interactions at both solid/water and air/water interfaces in different material systems have been reviewed. On the basis of surface forces apparatus (SFA) measurements of hydrophobic polymers (e.g., polystyrene), a three-regime hydrophobic interaction model that could satisfactorily encompass the hydrophobic interaction with different ranges was proposed. In addition, the atomic force microscope (AFM) coupled with various techniques such as the colloidal probe, the electrochemical process, and force mapping were employed to quantify the hydrophobic interaction from different perspectives. For the hydrophobic interactions involving deformable bubbles, the bubble probe AFM combined with reflection interference contrast microscopy (RICM) was used to simultaneously measure the interaction force and spatiotemporal evolution of the thin film drainage process between air bubbles and hydrophobized mica surfaces in an aqueous medium. The studies on the interactions of air bubbles with self-assembled monolayers (SAMs) demonstrated that the range of hydrophobic interactions does not always increase monotonically with the hydrophobicity of interacting surfaces as characterized by the static water contact angle; viz., surfaces with similar hydrophobicity can exhibit different ranges of hydrophobic interaction, while surfaces with different hydrophobicities can exhibit a similar range of hydrophobic interactions. It is found that the hydrophobic interaction can be modulated by tuning the surface nanoscale structure and chemistry. Moreover, the long-range "hydrophilic" attraction that resembles the hydrophobic interaction was discovered between water droplets and polyelectrolyte surfaces in an oil medium, on the basis of which polyelectrolyte coating materials were designed for oil cleaning, oil/water separation, and demulsification. The interfacial applications, remaining challenges, and future perspectives of hydrophobic interactions are discussed.
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Affiliation(s)
- Lei Xie
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xin Cui
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Lu Gong
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jingsi Chen
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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15
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Chu M, Miller M, Dutta P. Interfacial Density Profiles of Polar and Nonpolar Liquids at Hydrophobic Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:906-910. [PMID: 31913043 DOI: 10.1021/acs.langmuir.9b03785] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A density-depleted region ("gap") is known to exist between water and hydrophobic surfaces. Using X-ray reflectivity, we have observed similar gaps between hydrophobic self-assembled monolayers (SAMs) and four other polar liquids. For these liquids and for water, the observed electron density depletion is nonzero and is in most cases slightly greater than the depletion attributable to the layer of hydrogen atoms at the SAM surface. On the other hand, the observed X-ray reflectivity from the interfaces between SAMs and three nonpolar liquids studied can be explained either without gaps or with smaller gaps. Thus, polar liquids (including but not limited to water) stand away from even the terminal hydrogen atoms at hydrophobic surfaces, while nonpolar liquids interpenetrate the terminal region. There is no consistent correlation between the sizes of the gaps and the liquid-SAM contact angles, the relative polarities of the polar liquids, or their bulk densities.
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Affiliation(s)
- Miaoqi Chu
- Department of Physics and Astronomy , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3112 , United States
| | - Mitchell Miller
- Department of Physics and Astronomy , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3112 , United States
| | - Pulak Dutta
- Department of Physics and Astronomy , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3112 , United States
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16
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Qiao Y, Zhou H, Jiang Z, He Q, Gan S, Wang H, Wen S, de Pablo J, Liu Y, Tirrell MV, Chen W. An in situ shearing x-ray measurement system for exploring structures and dynamics at the solid-liquid interface. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:013908. [PMID: 32012592 DOI: 10.1063/1.5129819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/05/2020] [Indexed: 06/10/2023]
Abstract
Revealing interfacial structure and dynamics has been one of the essential thematic topics in material science and condensed matter physics. Synchrotron-based x-ray scattering techniques can deliver unique and insightful probing of interfacial structures and dynamics, in particular, in reflection geometries with higher surface and interfacial sensitivity than transmission geometries. We demonstrate the design and implementation of an in situ shearing x-ray measurement system, equipped with both inline parallel-plate and cone-and-plate shearing setups and operated at the advanced photon source at Argonne National Laboratory, to investigate the structures and dynamics of end-tethered polymers at the solid-liquid interface. With a precise lifting motor, a micrometer-scale gap can be produced by aligning two surfaces of a rotating upper shaft and a lower sample substrate. A torsional shear flow forms in the gap and applies tangential shear forces on the sample surface. The technical combination with nanoscale rheology and the utilization of in situ x-ray scattering allow us to gain fundamental insights into the complex dynamics in soft interfaces under shearing. In this work, we demonstrate the technical scope and experimental capability of the in situ shearing x-ray system through the measurements of charged polymers at both flat and curved interfaces upon shearing. Through the in situ shearing x-ray scattering experiments integrated with theoretical simulations, we aim to develop a detailed understanding of the short-range molecular structure and mesoscale ionic aggregate morphology, as well as ion transport and dynamics in soft interfaces, thereby providing fundamental insight into a long-standing challenge in ionic polymer brushes with a significant technological impact.
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Affiliation(s)
- Yijun Qiao
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Zhang Jiang
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Qiming He
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Shenglong Gan
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Hongdong Wang
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Shizhu Wen
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Juan de Pablo
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Yuhong Liu
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
| | - Matthew V Tirrell
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Wei Chen
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
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17
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Cao S, Konovalov KA, Unarta IC, Huang X. Recent Developments in Integral Equation Theory for Solvation to Treat Density Inhomogeneity at Solute–Solvent Interface. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Siqin Cao
- Department of Chemistrythe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Center of System Biology and Human HealthState Key Laboratory of Molecular Neuroscience, Hong Kong Branch Clear Water Bay Kowloon Hong Kong
| | - Kirill A. Konovalov
- Department of Chemistrythe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Center of System Biology and Human HealthState Key Laboratory of Molecular Neuroscience, Hong Kong Branch Clear Water Bay Kowloon Hong Kong
| | - Ilona Christy Unarta
- Center of System Biology and Human HealthState Key Laboratory of Molecular Neuroscience, Hong Kong Branch Clear Water Bay Kowloon Hong Kong
- Bioengineering Graduate Programthe Hong Kong University of Science and TechnologyHong Kong of Chinese National EngineeringResearch Center for Tissue Restoration and Reconstructionthe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Xuhui Huang
- Department of Chemistrythe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Center of System Biology and Human HealthState Key Laboratory of Molecular Neuroscience, Hong Kong Branch Clear Water Bay Kowloon Hong Kong
- Bioengineering Graduate Programthe Hong Kong University of Science and TechnologyHong Kong of Chinese National EngineeringResearch Center for Tissue Restoration and Reconstructionthe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- HKUST‐Shenzhen Research Institute Hi‐Tech Park, Nanshan Shenzhen 518057 China
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18
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Shaat M, Zheng Y. Fluidity and phase transitions of water in hydrophobic and hydrophilic nanotubes. Sci Rep 2019; 9:5689. [PMID: 30952907 PMCID: PMC6450949 DOI: 10.1038/s41598-019-42101-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/21/2018] [Indexed: 01/14/2023] Open
Abstract
We put water flow under scrutiny to report radial distributions of water viscosity within hydrophobic and hydrophilic nanotubes as functions of the water-nanotube interactions ([Formula: see text]), surface wettability (θ), and nanotube size (R) using a proposed hybrid continuum-molecular mechanics. Based on the computed viscosity data, [Formula: see text] phase diagram of the phase transitions of confined water in nanotubes is developed. It is revealed that water exhibits different multiphase structures, and the formation of one of these structures depends on [Formula: see text] R parameters. A drag of water flow at the first water layer is revealed, which is conjugate to sharp increase in the viscosity and formation of an ice phase under severe confinement (R ≤ 3.5 nm) and strong water-nanotube interaction conditions. A vapor/vapor-liquid phase is observed at hydrophobic and hydrophilic interfaces. A state of confinement is revealed at which water exhibits different multiphase structures under the same flow rate. The derived viscosity functions are used to accurately determine factors of flow enhancement/inhibition of confined water.
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Affiliation(s)
- Mohamed Shaat
- Department of Mechanical Engineering, Zagazig University, Zagazig, 44511, Egypt.
- Mechanical Engineering Department, Abu Dhabi University, Al Ain, P.O.BOX 1790, United Arab Emirates.
- Engineering and Manufacturing Technologies Department, DACC, New Mexico State University, Las Cruces, NM, 88003, USA.
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education School of Chemistry, and Beijing Advanced Innovation Center for Biomedical Engineering Beihang University (BUAA), Beijing, 100191, P. R. China
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19
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Mathur A, Pal D, Singh A, Sengupta A, Singh R, Chattopadhyay S. Violet Emission of ALD-Grown ZnO Nanostructures on Confined Polymer Films: Defect Origins and Emission Control via Interface Engineering Based on Confinement of the Bottom Polymer Template. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201800435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Aakash Mathur
- Discipline of Metallurgy Engineering and Materials Science; Indian Institute of Technology Indore; Indore 453552 India
| | - Dipayan Pal
- Discipline of Metallurgy Engineering and Materials Science; Indian Institute of Technology Indore; Indore 453552 India
| | - Ajaib Singh
- Discipline of Metallurgy Engineering and Materials Science; Indian Institute of Technology Indore; Indore 453552 India
| | - Amartya Sengupta
- Department of Physics; Indian Institute of Technology Delhi; Delhi 110016 India
| | - Rinki Singh
- Discipline of Biosciences and Biomedical Engineering; Indian Institute of Technology Indore; Indore 453552 India
| | - Sudeshna Chattopadhyay
- Discipline of Physics; Discipline of Metallurgy Engineering and Materials Science; Discipline of Biosciences and Biomedical Engineering; Indian Institute of Technology Indore; Indore 453552 India
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20
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Tomko JA, Olson DH, Giri A, Gaskins JT, Donovan BF, O'Malley SM, Hopkins PE. Nanoscale Wetting and Energy Transmission at Solid/Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2106-2114. [PMID: 30624942 DOI: 10.1021/acs.langmuir.8b03675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding the effects and limitations of solid/liquid interfaces on energy transport is crucial to applications ranging from nanoscale thermal engineering to chemical synthesis. Until now, the majority of experimental evidence regarding solid/liquid interactions has been limited to macroscale observations and experiments. The lack of experimental works exploring nanoscale solid/liquid interactions has been accentuated as the body of knowledge from theory and simulations at these scales has exploded in recent years. In this study, we expand on current nanoscale thermal measurement techniques in order to more fully understand solid/liquid interfacial energy transport. We use thermal ablation threshold measurements on thick Au films in various liquids as a metric to describe thermal transport at the Au/liquid interface. Furthermore, using ultrafast pump-probe experiments, we gain insight into this transport through picosecond ultrasonic coupling at solid/liquid interfaces with known macroscopic observations. We find significant variations in both the ablation threshold and the damping of the acoustic modes within the Au films depending on nanoscopic interactions at the solid/liquid interface rather than typical macroscale metrics such as acoustic mismatch, measured contact angle, and work of adhesion.
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Affiliation(s)
| | | | | | | | - Brian F Donovan
- Department of Physics , United States Naval Academy , Annapolis , Maryland 21402 , United States
| | - Sean M O'Malley
- Department of Physics , Rutgers University-Camden , Camden , New Jersey 08102 , United States
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21
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Pye JE, Wood CE, Burton JC. Precursors to Molecular Slip on Smooth Hydrophobic Surfaces. PHYSICAL REVIEW LETTERS 2018; 121:134501. [PMID: 30312092 DOI: 10.1103/physrevlett.121.134501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Indexed: 06/08/2023]
Abstract
Experiments and simulations suggest that simple liquids may experience slip while flowing near a smooth, hydrophobic surface. Here we show how precursors to molecular slip can be observed in the complex response of a liquid to oscillatory shear. We measure both the change in frequency and bandwidth of a quartz crystal microbalance during the growth of a single drop of water immersed in an ambient liquid. By varying the hydrophobicity of the surface using self-assembled monolayers, our results show little or no slip for water on all surfaces. However, we observe excess transverse motion near hydrophobic surfaces due to weak binding in the corrugated surface potential, an essential precursor to slip. We also show how this effect can be easily missed in simulations utilizing finite-ranged interaction potentials.
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Affiliation(s)
- Justin E Pye
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Clay E Wood
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Justin C Burton
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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22
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Schlesinger I, Sivan U. Three-Dimensional Characterization of Layers of Condensed Gas Molecules Forming Universally on Hydrophobic Surfaces. J Am Chem Soc 2018; 140:10473-10481. [DOI: 10.1021/jacs.8b04815] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Itai Schlesinger
- Department of Physics and the Russell Berrie Nanotechnology Institute, Technion − Israel Institute of Technology, Haifa 3200003, Israel
| | - Uri Sivan
- Department of Physics and the Russell Berrie Nanotechnology Institute, Technion − Israel Institute of Technology, Haifa 3200003, Israel
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23
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Evans R, Stewart MC, Wilding NB. Drying and wetting transitions of a Lennard-Jones fluid: Simulations and density functional theory. J Chem Phys 2017; 147:044701. [DOI: 10.1063/1.4993515] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Robert Evans
- H. H. Wills Physics Laboratory, University of Bristol, Royal Fort, Bristol BS8 1TL, United Kingdom
| | - Maria C. Stewart
- H. H. Wills Physics Laboratory, University of Bristol, Royal Fort, Bristol BS8 1TL, United Kingdom
| | - Nigel B. Wilding
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
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24
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Grudinin S, Garkavenko M, Kazennov A. Pepsi-SAXS: an adaptive method for rapid and accurate computation of small-angle X-ray scattering profiles. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2017; 73:449-464. [PMID: 28471369 DOI: 10.1107/s2059798317005745] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 04/15/2017] [Indexed: 11/10/2022]
Abstract
A new method called Pepsi-SAXS is presented that calculates small-angle X-ray scattering profiles from atomistic models. The method is based on the multipole expansion scheme and is significantly faster compared with other tested methods. In particular, using the Nyquist-Shannon-Kotelnikov sampling theorem, the multipole expansion order is adapted to the size of the model and the resolution of the experimental data. It is argued that by using the adaptive expansion order, this method has the same quadratic dependence on the number of atoms in the model as the Debye-based approach, but with a much smaller prefactor in the computational complexity. The method has been systematically validated on a large set of over 50 models collected from the BioIsis and SASBDB databases. Using a laptop, it was demonstrated that Pepsi-SAXS is about seven, 29 and 36 times faster compared with CRYSOL, FoXS and the three-dimensional Zernike method in SAStbx, respectively, when tested on data from the BioIsis database, and is about five, 21 and 25 times faster compared with CRYSOL, FoXS and SAStbx, respectively, when tested on data from SASBDB. On average, Pepsi-SAXS demonstrates comparable accuracy in terms of χ2 to CRYSOL and FoXS when tested on BioIsis and SASBDB profiles. Together with a small allowed variation of adjustable parameters, this demonstrates the effectiveness of the method. Pepsi-SAXS is available at http://team.inria.fr/nano-d/software/pepsi-saxs.
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Affiliation(s)
| | - Maria Garkavenko
- Moscow Institute of Physics and Technology, Dolgoprudniy, Russian Federation
| | - Andrei Kazennov
- Moscow Institute of Physics and Technology, Dolgoprudniy, Russian Federation
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25
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Ultrahigh Responsivity and Detectivity Graphene-Perovskite Hybrid Phototransistors by Sequential Vapor Deposition. Sci Rep 2017; 7:46281. [PMID: 28422117 PMCID: PMC5395820 DOI: 10.1038/srep46281] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/09/2017] [Indexed: 11/09/2022] Open
Abstract
In this work, graphene-methylammonium lead iodide (MAPbI3) perovskite hybrid phototransistors fabricated by sequential vapor deposition are demonstrated. Ultrahigh responsivity of 1.73 × 107 A W−1 and detectivity of 2 × 1015 Jones are achieved, with extremely high effective quantum efficiencies of about 108% in the visible range (450–700 nm). This excellent performance is attributed to the ultra-flat perovskite films grown by vapor deposition on the graphene sheets. The hybrid structure of graphene covered with uniform perovskite has high exciton separation ability under light exposure, and thus efficiently generates photocurrents. This paper presents photoluminescence (PL) images along with statistical analysis used to study the photo-induced exciton behavior. Both uniform and dramatic PL intensity quenching has been observed over entire measured regions, consistently demonstrating excellent exciton separation in the devices.
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26
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Chen D, Gelenter MD, Hong M, Cohen RE, McKinley GH. Icephobic Surfaces Induced by Interfacial Nonfrozen Water. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4202-4214. [PMID: 28054770 PMCID: PMC6911363 DOI: 10.1021/acsami.6b13773] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
It is known that smooth, hydrophobic solid surfaces exhibit low ice adhesion values, which have been shown to approach a lower ice adhesion strength limit (∼150 kPa) defined by the water receding contact angle. To overcome this limit, we have designed self-lubricating icephobic coatings by blending polydimethylsiloxane (PDMS)-poly(ethylene glycol) (PEG) amphiphilic copolymers into a polymer matrix. Such coatings provide low ice adhesion strength values (∼50 kPa) that can substantially reduce the lower bound of the ice adhesion strength achieved previously on smooth, hydrophobic solid surfaces. Different molecular mechanisms are responsible for the low ice adhesion strength attained by these two approaches. For the smooth hydrophobic surfaces, an increased water depletion layer thickness at the interface weakens the van der Waals' interactions between the ice and the polymeric substrate. For the self-lubricating icephobic coatings, the PEG component of the amphiphilic copolymer is capable of strongly hydrogen bonding with water molecules. The surface hydrogen-bonded water molecules do not freeze, even at substantial levels of subcooling, and therefore serve as a self-lubricating interfacial liquid-like layer that helps to reduce the adhesion strength of ice to the surface. The existence of nonfrozen water molecules at the ice-solid interface is confirmed by solid-state nuclear magnetic resonance (NMR) spectroscopy.
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Affiliation(s)
- Dayong Chen
- Department of Chemical Engineering, Massachusetts Institute of Technology
- Department of Mechanical Engineering, Massachusetts Institute of Technology
| | | | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology
| | - Robert E. Cohen
- Department of Chemical Engineering, Massachusetts Institute of Technology
- Corresponding authors: Robert E. Cohen, Fax: 01 617 258 8224. , Gareth H. McKinley, Fax: 01 617 258 8559.
| | - Gareth H. McKinley
- Department of Mechanical Engineering, Massachusetts Institute of Technology
- Corresponding authors: Robert E. Cohen, Fax: 01 617 258 8224. , Gareth H. McKinley, Fax: 01 617 258 8559.
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27
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Lozynski M, Pernak J, Gdaniec Z, Gorska B, Béguin F. Proof of ion-pair structures in ammonium-based protic ionic liquids using combined NMR and DFT/PCM-based chemical shift calculations. Phys Chem Chem Phys 2017; 19:25033-25043. [DOI: 10.1039/c7cp04481j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The self-assembly of triethylammonium bis(trifluoromethylsulfonyl)imide, i.e. [(C2H5)3NH][TFSI], in chloroform and aqueous solutions has been investigated using 1H NMR spectroscopy and computational (DFT/PCM prediction) methods.
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Affiliation(s)
- M. Lozynski
- Faculty of Chemical Technology
- Poznan University of Technology
- 60-965 Poznan
- Poland
| | - J. Pernak
- Faculty of Chemical Technology
- Poznan University of Technology
- 60-965 Poznan
- Poland
| | - Z. Gdaniec
- Institute of Bioorganic Chemistry
- Polish Academy of Sciences
- 61-704 Poznan
- Poland
| | - B. Gorska
- Faculty of Chemical Technology
- Poznan University of Technology
- 60-965 Poznan
- Poland
| | - F. Béguin
- Faculty of Chemical Technology
- Poznan University of Technology
- 60-965 Poznan
- Poland
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28
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Fukuto M, Ocko BM, Bonthuis DJ, Netz RR, Steinrück HG, Pontoni D, Kuzmenko I, Haddad J, Deutsch M. Nanoscale Structure of the Oil-Water Interface. PHYSICAL REVIEW LETTERS 2016; 117:256102. [PMID: 28036213 DOI: 10.1103/physrevlett.117.256102] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Indexed: 06/06/2023]
Abstract
X-ray reflectivity (XR) and atomistic molecular dynamics (MD) simulations, carried out to determine the structure of the oil-water interface, provide new insight into the simplest liquid-liquid interface. For several oils (hexane, dodecane, and hexadecane) the XR shows very good agreement with a monotonic interface-normal electron density profile (EDP) broadened only by capillary waves. Similar agreement is also found for an EDP including a sub-Å thick electron depletion layer separating the oil and the water. The XR and MD derived depletions are much smaller than reported for the interface between solid-supported hydrophobic monolayers and water.
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Affiliation(s)
- M Fukuto
- Condensed Matter Physics and Materials Sciences Department and NSLS II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - B M Ocko
- Condensed Matter Physics and Materials Sciences Department and NSLS II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - D J Bonthuis
- Rudolf Peierls Centre for Theoretical Physics, Oxford University, 1 Keble Road, Oxford OX1 3NP, United Kingdom
| | - R R Netz
- Department of Physics, Free University Berlin, D-14195 Berlin, Germany
| | - H-G Steinrück
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Pontoni
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - I Kuzmenko
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - J Haddad
- Physics Department and Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - M Deutsch
- Physics Department and Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900, Israel
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29
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Björneholm O, Hansen MH, Hodgson A, Liu LM, Limmer DT, Michaelides A, Pedevilla P, Rossmeisl J, Shen H, Tocci G, Tyrode E, Walz MM, Werner J, Bluhm H. Water at Interfaces. Chem Rev 2016; 116:7698-726. [PMID: 27232062 DOI: 10.1021/acs.chemrev.6b00045] [Citation(s) in RCA: 358] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding.
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Affiliation(s)
- Olle Björneholm
- Department of Physics and Astronomy, Uppsala University , Box 516, 751 20 Uppsala, Sweden
| | - Martin H Hansen
- Technical University of Denmark , 2800 Kongens Lyngby, Denmark.,Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Andrew Hodgson
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Li-Min Liu
- Thomas Young Centre, London Centre for Nanotechnology, Department of Physics and Astronomy, and Department of Chemistry, University College London , London WC1E 6BT, United Kingdom.,Beijing Computational Science Research Center , Beijing, 100193, China
| | - David T Limmer
- Princeton Center for Theoretical Science, Princeton University , Princeton, New Jersey 08544, United States
| | - Angelos Michaelides
- Thomas Young Centre, London Centre for Nanotechnology, Department of Physics and Astronomy, and Department of Chemistry, University College London , London WC1E 6BT, United Kingdom
| | - Philipp Pedevilla
- Thomas Young Centre, London Centre for Nanotechnology, Department of Physics and Astronomy, and Department of Chemistry, University College London , London WC1E 6BT, United Kingdom
| | - Jan Rossmeisl
- Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Huaze Shen
- International Center for Quantum Materials and School of Physics, Peking University , Beijing 100871, China
| | - Gabriele Tocci
- Thomas Young Centre, London Centre for Nanotechnology, Department of Physics and Astronomy, and Department of Chemistry, University College London , London WC1E 6BT, United Kingdom.,Laboratory for fundamental BioPhotonics, Laboratory of Computational Science and Modeling, Institutes of Bioengineering and Materials Science and Engineering, School of Engineering, and Lausanne Centre for Ultrafast Science, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Eric Tyrode
- Department of Chemistry, KTH Royal Institute of Technology , 10044 Stockholm, Sweden
| | - Marie-Madeleine Walz
- Department of Physics and Astronomy, Uppsala University , Box 516, 751 20 Uppsala, Sweden
| | - Josephina Werner
- Department of Physics and Astronomy, Uppsala University , Box 516, 751 20 Uppsala, Sweden.,Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences , Box 7015, 750 07 Uppsala, Sweden
| | - Hendrik Bluhm
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
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30
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31
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Cao F, Liu Y, Xu J, He Y, Hammouda B, Qiao R, Yang B. Probing Nanoscale Thermal Transport in Surfactant Solutions. Sci Rep 2015; 5:16040. [PMID: 26534840 PMCID: PMC4631999 DOI: 10.1038/srep16040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/23/2015] [Indexed: 01/07/2023] Open
Abstract
Surfactant solutions typically feature tunable nanoscale, internal structures. Although rarely utilized, they can be a powerful platform for probing thermal transport in nanoscale domains and across interfaces with nanometer-size radius. Here, we examine the structure and thermal transport in solution of AOT (Dioctyl sodium sulfosuccinate) in n-octane liquids using small-angle neutron scattering, thermal conductivity measurements, and molecular dynamics simulations. We report the first experimental observation of a minimum thermal conductivity occurring at the critical micelle concentration (CMC): the thermal conductivity of the surfactant solution decreases as AOT is added till the onset of micellization but increases as more AOT is added. The decrease of thermal conductivity with AOT loading in solutions in which AOT molecules are dispersed as monomers suggests that even the interfaces between individual oleophobic headgroup of AOT molecules and their surrounding non-polar octane molecules can hinder heat transfer. The increase of thermal conductivity with AOT loading after the onset of micellization indicates that the thermal transport in the core of AOT micelles and across the surfactant-oil interfaces, both of which span only a few nanometers, are efficient.
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Affiliation(s)
- Fangyu Cao
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
| | - Ying Liu
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jiajun Xu
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
| | - Yadong He
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - B. Hammouda
- Center for Neutron Research, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Stop 6102, Gaithersburg, MD 20899 USA
| | - Rui Qiao
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Bao Yang
- Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
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32
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Mechanisms for Enhanced Hydrophobicity by Atomic-Scale Roughness. Sci Rep 2015; 5:13790. [PMID: 26337567 PMCID: PMC4559767 DOI: 10.1038/srep13790] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/05/2015] [Indexed: 11/25/2022] Open
Abstract
It is well known that the close-packed CF3-terminated solid surface is among the most hydrophobic surfaces in nature. Molecular dynamic simulations show that this hydrophobicity can be further enhanced by the atomic-scale roughness. Consequently, the hydrophobic gap width is enlarged to about 0.6 nm for roughened CF3-terminated solid surfaces. In contrast, the hydrophobic gap width does not increase too much for a rough CH3-terminated solid surface. We show that the CF3-terminated surface exists in a microscopic Cassie–Baxter state, whereas the CH3-terminated surface exists as a microscopic Wenzel state. This finding elucidates the underlying mechanism for the different widths of the observed hydrophobic gap. The cage structure of the water molecules (with integrated hydrogen bonds) around CH3 terminal assemblies on the solid surface provides an explanation for the mechanism by which the CH3-terminated surface is less hydrophobic than the CF3-terminated surface.
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Evans R, Wilding NB. Quantifying Density Fluctuations in Water at a Hydrophobic Surface: Evidence for Critical Drying. PHYSICAL REVIEW LETTERS 2015; 115:016103. [PMID: 26182111 DOI: 10.1103/physrevlett.115.016103] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 06/04/2023]
Abstract
Employing smart Monte Carlo sampling techniques within the grand canonical ensemble, we investigate the properties of water at a model hydrophobic substrate. By reducing the strength of substrate-water attraction, we find that fluctuations in the local number density, quantified by a rigorous definition of the local compressibility χ(z), increase rapidly for distances z within one or two molecular diameters from the substrate as the degree of hydrophobicity, measured by the macroscopic contact angle θ, increases. Our simulations provide evidence for a continuous (critical) drying transition as the substrate-water interaction becomes very weak: cos(θ)→-1. We speculate that the existence of such a transition might account for earlier simulation observations of strongly enhanced density fluctuations.
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Affiliation(s)
- Robert Evans
- H. H. Wills Physics Laboratory, University of Bristol, Royal Fort, Bristol BS8 1TL, United Kingdom
| | - Nigel B Wilding
- Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom
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Kienle DF, Kuhl TL. Analyzing refractive index profiles of confined fluids by interferometry. Anal Chem 2014; 86:11860-7. [PMID: 25365770 DOI: 10.1021/ac503469x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work describes an interferometry data analysis method for determining the optical thickness of thin films or any variation in the refractive index of a fluid or film near a surface. In particular, the method described is applied to the analysis of interferometry data taken with a surface force apparatus (SFA). The technique does not require contacting or confining the fluid or film. By analyzing interferometry data taken at many intersurface separation distances out to at least 300 nm, the properties of a film can be quantitatively determined. The film can consist of material deposited on the surface, like a polymer brush, or variation in a fluid's refractive index near a surface resulting from, for example, a concentration gradient, depletion in density, or surface roughness. The method is demonstrated with aqueous polyethylenimine (PEI) adsorbed onto mica substrates, which has a large concentration and therefore refractive index gradient near the mica surface. The PEI layer thickness determined by the proposed method is consistent with the thickness measured by conventional SFA methods. Additionally, a thorough investigation of the effects of random and systematic error in SFA data analysis and modeling via simulations of interferometry is described in detail.
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Affiliation(s)
- Daniel F Kienle
- Department of Chemical Engineering and Materials Science, University of California Davis , Davis, California 95616, United States
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Lee H, Tsouris V, Lim Y, Mustafa R, Choi J, Choi YH, Park HW, Meron M, Lin B, Won YY. Macroscopic lateral heterogeneity observed in a laterally mobile immiscible mixed polyelectrolyte-neutral polymer brush. SOFT MATTER 2014; 10:3771-82. [PMID: 24695635 PMCID: PMC4397986 DOI: 10.1039/c4sm00022f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We studied mixed poly(ethylene oxide) (PEO) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes. The question we attempted to answer was: when the chain grafting points are laterally mobile, how will this lateral mobility influence the structure and phase behavior of the mixed brush? Three different model mixed PEO/PDMAEMA brush systems were prepared: (1) a laterally mobile mixed brush by spreading onto the air-water interface a mixture of poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) and poly(2-(dimethylamino)ethyl methacrylate)-poly(n-butyl acrylate) (PDMAEMA-PnBA) diblock copolymers (the specific diblock copolymers used will be denoted as PEO113-PnBA100 and PDMAEMA118-PnBA100, where the subscripts refer to the number-average degrees of polymerization of the individual blocks), (2) a mobility-restricted (inseparable) version of the above mixed brush prepared using a PEO-PnBA-PDMAEMA triblock copolymer (denoted as PEO113-PnBA89-PDMAEMA120) having respective brush molecular weights matched with those of the diblock copolymers, and (3) a different laterally mobile mixed PEO and PDMAEMA brush prepared from a PEO113-PnBA100 and PDMAEMA200-PnBA103 diblock copolymer combination, which represents a further more height-mismatched mixed brush situation than described in (1). These three mixed brush systems were investigated by surface pressure-area isotherm and X-ray (XR) reflectivity measurements. These experimental data were analyzed within the theoretical framework of a continuum self-consistent field (SCF) polymer brush model. The combined experimental and theoretical results suggest that the mobile mixed brush derived using the PEO113-PnBA100 and PDMAEMA118-PnBA100 combination (i.e., mixed brush System #1) undergoes a lateral macroscopic phase separation at high chain grafting densities, whereas the more height-mismatched system (System #3) is only microscopically phase separated under comparable brush density conditions even though the lateral mobility of the grafted chains is unrestricted. The macroscopic phase separation observed in the laterally mobile mixed brush system is in contrast with the microphase separation behavior commonly observed in two-dimensional laterally mobile charged small molecule mixtures. Further study is needed to determine the detailed morphologies of the macro- and microphase-separated mixed PEO/PDMAEMA brushes.
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Affiliation(s)
- Hoyoung Lee
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
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36
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David R, Neumann AW. Contact angle patterns on low-energy surfaces. Adv Colloid Interface Sci 2014; 206:46-56. [PMID: 23601233 DOI: 10.1016/j.cis.2013.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/27/2013] [Accepted: 03/14/2013] [Indexed: 10/27/2022]
Abstract
It is well-known that on a given low-energy solid surface, the contact angles of different organic liquids follow a regular pattern. The experimental evidence for this, and semi-empirical equations describing the pattern, are reviewed. Theoretical and computational efforts to explain the pattern are discussed, and a simplified analytical approach is presented. The main pattern of contact angles is seen to arise from two factors: a common combining rule for liquid-solid molecular interactions, and the reduced density of liquid molecules adjacent to a lower-energy solid surface. Irregular departures from the main pattern are due to chemical effects originating in molecular structure.
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Wirkert FJ, Paulus M, Nase J, Möller J, Kujawski S, Sternemann C, Tolan M. X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:76-81. [PMID: 24365919 DOI: 10.1107/s1600577513021516] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/01/2013] [Indexed: 06/03/2023]
Abstract
A high-pressure cell for in situ X-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for the in situ investigation of adsorption phenomena in biological systems.
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Affiliation(s)
| | - Michael Paulus
- Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany
| | - Julia Nase
- Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany
| | | | - Simon Kujawski
- Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany
| | | | - Metin Tolan
- Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany
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38
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Chakraborty J, Chakraborty S. Influence of hydrophobic effects on streaming potential. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:043007. [PMID: 24229276 DOI: 10.1103/physreve.88.043007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Indexed: 06/02/2023]
Abstract
We study the influence of hydrophobic effects on streaming potential mediated flow through a narrow confinement. In a clear departure from the approach used in prior works, we use a phase-field model to capture the hydrophobicity-induced depletion in the near wall region, and express the variation of viscosity and permittivity across the interfacial layer in terms of the phase-field variable. We then use these in the determination of the flow velocity, and highlight the sensitive interplay between the intrinsic length scale of the electrical double layer and that of the depletion in terms of the variations of an effective normalized viscosity that captures the electroviscous effect. We expect that this work will be an important step forward in the realistic continuum modeling of interfacial physics in the particular context of streaming potential mediated flows.
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Affiliation(s)
- Jeevanjyoti Chakraborty
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur-721302, India
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39
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Richter AG, Kuzmenko I. Using in situ X-ray reflectivity to study protein adsorption on hydrophilic and hydrophobic surfaces: benefits and limitations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5167-5180. [PMID: 23586436 DOI: 10.1021/la3049532] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have employed in situ X-ray reflectivity (IXRR) to study the adsorption of a variety of proteins (lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and immunoglobulin G) on model hydrophilic (silicon oxide) and hydrophobic surfaces (octadecyltrichlorosilane self-assembled monolayers), evaluating this recently developed technique for its applicability in the area of biomolecular studies. We report herein the highest resolution depiction of adsorbed protein films, greatly improving on the precision of previous neutron reflectivity (NR) results and previous IXRR studies. We were able to perform complete scans in 5 min or less with the maximum momentum transfer of at least 0.52 Å(-1), allowing for some time-resolved information about the evolution of the protein film structure. The three smallest proteins (lysozyme, cytochrome c, and myoglobin) were seen to deposit as fully hydrated, nondenatured molecules onto hydrophilic surfaces, with indications of particular preferential orientations. Time evolution was observed for both lysozyme and myoglobin films. The larger proteins were not observed to deposit on the hydrophilic substrates, perhaps because of contrast limitations. On hydrophobic surfaces, all proteins were seen to denature extensively in a qualitatively similar way but with a rough trend that the larger proteins resulted in lower coverage. We have generated high-resolution electron density profiles of these denatured films, including capturing the growth of a lysozyme film. Because the solution interface of these denatured films is diffuse, IXRR cannot unambiguously determine the film extent and coverage, a drawback compared to NR. X-ray radiation damage was systematically evaluated, including the controlled exposure of protein films to high-intensity X-rays and exposure of the hydrophobic surface to X-rays before adsorption. Our analysis showed that standard measuring procedures used for XRR studies may lead to altered protein films; therefore, we used modified procedures to limit the influence of X-ray damage.
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Affiliation(s)
- Andrew G Richter
- Department of Physics and Astronomy, Valparaiso University, Valparaiso, Indiana 46383, USA.
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40
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Gutfreund P, Bäumchen O, Fetzer R, van der Grinten D, Maccarini M, Jacobs K, Zabel H, Wolff M. Solid surface structure affects liquid order at the polystyrene-self-assembled-monolayer interface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:012306. [PMID: 23410330 DOI: 10.1103/physreve.87.012306] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 11/22/2012] [Indexed: 06/01/2023]
Abstract
We present a combined x-ray and neutron reflectivity study characterizing the interface between polystyrene (PS) and silanized surfaces. Motivated by the large difference in slip velocity of PS on top of dodecyl-trichlorosilane (DTS) and octadecyl-trichlorosilane (OTS) found in previous studies, these two systems were chosen for the present investigation. The results reveal the molecular conformation of PS on silanized silicon. Differences in the molecular tilt of OTS and DTS are replicated by the adjacent phenyl rings of the PS. We discuss our findings in terms of a potential link between the microscopic interfacial structure and dynamic properties of polymeric liquids at interfaces.
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41
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Walker DE, Major M, Yazdi MB, Klyszcz A, Haeming M, Bonrad K, Melzer C, Donner W, von Seggern H. High mobility indium zinc oxide thin film field-effect transistors by semiconductor layer engineering. ACS APPLIED MATERIALS & INTERFACES 2012; 4:6835-6841. [PMID: 23163608 DOI: 10.1021/am302004j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Indium zinc oxide thin-film transistors are fabricated via a precursor in solution route on silicon substrates with silicon dioxide gate dielectric. It is found that the extracted mobility rises, peaks, and then decreases with increasing precursor concentration instead of rising and saturating. Investigation with scanning probe techniques reveals full thickness variations within the film which are assumed to adversely affect charge transport. Additional layers are coated, and the extracted mobility is observed to increase up to 19.7 cm(2) V(-1) s(-1). The reasons for this are examined in detail by direct imaging with scanning tunneling microscopy and extracting electron density profiles from X-ray reflection measurements. It is found that the optimal concentration for single layer films is suboptimal when coating multiple layers and in fact using many layers of very low concentrations of precursor in the solution, leading to a dense, defect and void free film, affording the highest mobilities. A consistent qualitative model of layer formation is developed explaining how the morphology of the film develops as the concentration of precursor in the initial solution is varied.
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Affiliation(s)
- Daniel E Walker
- Technical University of Darmstadt, Department of Materials Science, 64287 Darmstadt, Germany.
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42
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Mizukami M, Kobayashi A, Kurihara K. Structuring of interfacial water on silica surface in cyclohexane studied by surface forces measurement and sum frequency generation vibrational spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:14284-14290. [PMID: 22974462 DOI: 10.1021/la303003u] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We investigated interfacial water, formed by adsorption or phase separation (prewetting transition), on a silica surface in water-cyclohexane binary liquids using a combination of colloidal probe atomic force microscopy (AFM) and sum frequency generation (SFG) vibrational spectroscopy. At 33 ± 9 ppm water, the long-range attraction extending to 19.4 ± 2.9 nm appeared, which was caused by the contact of water layers formed on silica surfaces. The attraction range increased with increasing water concentration and reached 97 ± 17 nm at the saturation concentration of water in cyclohexane (C*), indicating that the thickness of the water layer formed on silica was ca. 50 nm. The interfacial energy between the water adsorption layer and bulk solution (γ = 79.3 ± 2.0 mN/m) was estimated from the pull-off force, and was significantly larger than the value for the bulk water/cyclohexane interface (γ = 50.1 mN/m). SFG spectroscopy demonstrated that the interfacial water formed an icelike structure at C*. These results indicated that the interfacial water molecules formed an icelike ordered structure induced by the hydrogen bonding with surface silanol groups, resulting in the free OH groups being more exposed to the bulk solution. On the other hand, the water adsorption layer induced by phase separation at water concentrations above C* was found to be less ordered and its structure at the adsorption layer/bulk interface was almost the same as that of bulk water, although its thickness was almost the same as that formed at C*. To our knowledge, this is the first report of the observation of liquid adsorption layers formed by chemical interaction up to saturation and by the wetting transition above saturation, and their differences in the structure and properties at the molecular level.
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Affiliation(s)
- Masashi Mizukami
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577, Japan
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43
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Muntean SA, Gerasimov RA, Lyulin AV. Dynamics of Water Near Oxidized Polystyrene Films. MACROMOL THEOR SIMUL 2012. [DOI: 10.1002/mats.201200025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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44
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Lee H, Kim DH, Park HW, Mahynski NA, Kim K, Meron M, Lin B, Won YY. Reduced Water Density in a Poly(ethylene oxide) Brush. J Phys Chem Lett 2012; 3:1589-1595. [PMID: 26285713 DOI: 10.1021/jz3002772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated under various grafting density conditions by using the X-ray reflectivity (XR) technique. The overall electron density profiles of the PEO-PnBA monolayer in the direction normal to the air-water interface were determined from the XR data. From this analysis, it was found that inside of the PEO brush, the water density is significantly lower than that of bulk water, in particular, in the region close to the PnBA-water interface. Separate XR measurements with a PnBA homopolymer monolayer confirm that the reduced water density within the PEO-PnBA monolayer is not due to unfavorable contacts between the PnBA surface and water. The above result, therefore, lends support to the notion that PEO chains provide a hydrophobic environment for the surrounding water molecules when they exist as polymer brush chains.
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Affiliation(s)
- Hoyoung Lee
- †School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Dae Hwan Kim
- †School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hae-Woong Park
- †School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Nathan A Mahynski
- †School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kyungil Kim
- ‡Advanced Photon Source, University of Chicago, Argonne, Illinois 60439, United States
| | - Mati Meron
- ‡Advanced Photon Source, University of Chicago, Argonne, Illinois 60439, United States
| | - Binhua Lin
- ‡Advanced Photon Source, University of Chicago, Argonne, Illinois 60439, United States
| | - You-Yeon Won
- †School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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45
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Jamadagni SN, Godawat R, Garde S. Hydrophobicity of proteins and interfaces: insights from density fluctuations. Annu Rev Chem Biomol Eng 2012; 2:147-71. [PMID: 22432614 DOI: 10.1146/annurev-chembioeng-061010-114156] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macroscopic characterizations of hydrophobicity (e.g., contact angle measurements) do not extend to the surfaces of proteins and nanoparticles. Molecular measures of hydrophobicity of such surfaces need to account for the behavior of hydration water. Theory and state-of-the-art simulations suggest that water density fluctuations provide such a measure; fluctuations are enhanced near hydrophobic surfaces and quenched with increasing surface hydrophilicity. Fluctuations affect conformational equilibria and dynamics of molecules at interfaces. Enhanced fluctuations are reflected in enhanced cavity formation, more favorable binding of hydrophobic solutes, increased compressibility of hydration water, and enhanced water-water correlations at hydrophobic surfaces. These density fluctuation-based measures can be used to develop practical methods to map the hydrophobicity/philicity of heterogeneous surfaces including those of proteins. They highlight that the hydrophobicity of a group is context dependent and is significantly affected by its environment (e.g., chemistry and topography) and especially by confinement. The ability to include information about hydration water in mapping hydrophobicity is expected to significantly impact our understanding of protein-protein interactions as well as improve drug design and discovery methods and bioseparation processes.
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Affiliation(s)
- Sumanth N Jamadagni
- The Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
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46
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Chakraborty J, Pati S, Som SK, Chakraborty S. Consistent description of electrohydrodynamics in narrow fluidic confinements in the presence of hydrophobic interactions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:046305. [PMID: 22680572 DOI: 10.1103/physreve.85.046305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Indexed: 06/01/2023]
Abstract
Electrohydrodynamics in the presence of hydrophobic interactions in narrow confinements is traditionally represented from a continuum viewpoint by a Navier slip-based conceptual paradigm, in which the slip length carries the sole burden of incorporating the effects of substrate wettability on interfacial electromechanics, precluding any explicit dependence of the interfacial potential distribution on the substrate wettability. Here we show that this traditional way of treating electrokinetics-wettability coupling may lead to serious discrepancies in predicting the resultant transport characteristics as manifested through an effective zeta potential. We suggest that an alternative consistent description of the underlying physics through a free-energy-based formalism, in conjunction with considerations of hydrodynamic and electrical property variations consistent with the pertinent phase-field description, may represent the underlying consequences in a more rational manner, as compared to the traditional slip-based model coupled with a two-layer description. Our studies further reveal that the above discrepancies may not occur solely due to the slip-based route of representing the interfacial wettability, but may be additionally attributed to the act of "discretizing" the interfacial phase fraction distribution through an artificial two-layer route.
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Affiliation(s)
- Jeevanjyoti Chakraborty
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur-721302, India
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47
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Segura JJ, Verdaguer A, Sacha GM, Fraxedas J. Dipolar origin of water etching of amino acid surfaces. Phys Chem Chem Phys 2011; 13:21446-50. [PMID: 22048449 DOI: 10.1039/c1cp22277e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The etching induced by water on hydrophobic (001) surfaces of enantiomeric L-, D- and racemic DL-valine crystals has been characterized by means of atomic force microscopy (AFM) at ambient conditions. Well-defined chiral parallelepipedic shallow patterns, one bilayer deep, are observed for the enantiomeric crystals with sides (steps) oriented along low index crystallographic directions. Hence, chirality can be readily identified by visual inspection of an AFM image after etching. The formation of such regular patterns can be rationalized using basic concepts of electrical dipolar interactions. The key factor that determines the relative etching rate for each step and thus defines the shape of the etching patterns is the orientation of the molecular dipoles with respect to the step edge. The simplicity of the approach allows the prediction of the effect of water etching on other amino acid crystals as well as the effect of the interaction of water with amino acid molecules forming part of more complex structures.
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Affiliation(s)
- J J Segura
- Centre d' Investigació en Nanociència i Nanotecnologia, Edifici CM-7, Campus UAB, Esfera UAB, E-08193 Bellaterra, Catalunya, Spain
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Mezger M, Reichert H, Ocko BM, Daillant J, Dosch H. Comment on "How water meets a very hydrophobic surface". PHYSICAL REVIEW LETTERS 2011; 107:249801-249802. [PMID: 22243027 DOI: 10.1103/physrevlett.107.249801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Indexed: 05/31/2023]
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49
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Walz M, Gerth S, Falus P, Klimczak M, Metzger TH, Magerl A. Nanoscale structures and dynamics of a boundary liquid layer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:324102. [PMID: 21795767 DOI: 10.1088/0953-8984/23/32/324102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Our long term scientific interest is the understanding of the interface properties of flowing liquids on a microscopic level. Various mechanisms have been introduced to explain the origin of slip at a solid-liquid interface like the formation of a thin depletion layer or a molecular ordering of the liquid near the interface. Reflectometry (using x-rays or neutrons) is a powerful technique to probe structures in this surface region. However, to date much less attention has been paid to the dynamical properties. In the first part of this paper we show that a different ordering of water exists next to a hydrophobic substrate in comparison to a hydrophilic interface. Furthermore, we find that shear has no effect on the depletion layer on hydrophobic substrates, while no depletion layer exists for hydrophilic surfaces. The second part of the paper addresses the dynamical properties of the boundary layer, and we present a new method which enables the observation of the diffusion dynamics of polymers next to a solid substrate. As a proof of concept, the dynamics of micelles next to the interface has been explored using grazing incidence neutron spin-echo spectroscopy. We were able to verify that investigation of the dynamics of the sample is feasible with this grazing incidence technique and we present data taken near the critical angle of total reflection. It appears that the diffusive motion of micelles at the hydrophobic (repulsive) interface is faster than at a hydrophilic interface or in the bulk. Furthermore, neutron spin-echo spectroscopy was extended to a first evaluation of the Doppler shift which occurs under flow.
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Affiliation(s)
- M Walz
- Crystallography and Structural Physics, Staudtstraße 3, University of Erlangen-Nürnberg, D-91058 Erlangen, Germany
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Le G, Zhang J. A general Poisson-Boltzmann model with position-dependent dielectric permittivity for electric double layer analysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5366-5370. [PMID: 21476554 DOI: 10.1021/la200596c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this paper, we propose a general Poisson-Boltzmann model for electric double layer (EDL) analysis with the position dependence of dielectric permittivity considered. This model provides physically reasonable property profiles in the EDL region, and it is then utilized to investigate the depletion layer effect on EDL structure and interaction near hydrophobic surfaces. Our results show that both the electric potential and the interaction pressure between surfaces decrease due to the lower permittivity in the depletion layer. The reduction becomes more profound at larger variation magnitude and range. This trend is in general agreement with that observed from the previous stepwise model; however, that model has overestimated the influence of permittivity variation effect. For the thin depletion layer and the relative thick EDL, our calculation indicates that the permittivity variation effect on EDL usually can be neglected. Furthermore, our model can be readily extended to study the permittivity variation in EDL due to ion accumulation and hydration in the EDL region.
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Affiliation(s)
- Guigao Le
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
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