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Li H, Wang J, Warr GG, Atkin R. Nanostructure and Dynamics of the Locally Concentrated Ionic Liquid 2:1 (wt:wt) HMIM FAP:TFTFE and HMIM FAP on Graphite and Gold Electrodes as a Function of Potential. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2403109. [PMID: 39105361 DOI: 10.1002/smll.202403109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 07/26/2024] [Indexed: 08/07/2024]
Abstract
Video-rate atomic force microscopy (AFM) is used to record the near-surface nanostructure and dynamics of one pure ionic liquid (IL), 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (HMIM FAP), and a locally-concentrated IL comprising HMIM FAP with the low viscosity diluent 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFTFE), on highly oriented pyrolytic graphite (HOPG) and Au(111) electrodes as a function of potential. Over the potential range measured (open-circuit potential ± 1 V), different near-surface nanostructures are observed. For pure HMIM FAP, globular aggregates align in rows on HOPG, whereas elongated and worm-like nanostructures form on Au(111). For 2:1 (wt:wt) HMIM FAP:TFTFE, larger and less defined diluent swollen IL aggregates are present on both electrodes. Long-lived near-surface nanostructures for HMIM FAP and the 2:1 (wt:wt) HMIM FAP:TFTFE persist on both electrodes. 2:1 (wt:wt) HMIM FAP:TFTFE mixture diffuses more rapidly than pure HMIM FAP on both electrodes with obviously higher diffusion coefficients on HOPG than on Au(111) due to weaker electrostatic and solvophobic interactions between near-surface aggregates and Stern layer ions. These outcomes provide valuable insights for a wide range of IL applications in interface sciences, including electrolytes, catalysts, lubricants, and sensors.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, 6009, Australia
| | - Jianan Wang
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
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2
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Wang H, Chen B, Sun H, Zhang Y. Carbon-based molecular properties efficiently predicted by deep learning-based quantum chemical simulation with large language models. Comput Biol Med 2024; 176:108531. [PMID: 38728991 DOI: 10.1016/j.compbiomed.2024.108531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 04/21/2024] [Accepted: 04/28/2024] [Indexed: 05/12/2024]
Abstract
The prediction of thermodynamic properties of carbon-based molecules based on their geometrical conformation using fluctuation and density functional theories has achieved great success in the field of energy chemistry, while the excessive computational cost provides both opportunities and challenges for the integration of machine learning. In this work, a deep learning-based quantum chemical prediction model was constructed for efficient prediction of thermodynamic properties of carbon-based molecules. We constructed a novel framework - encoding the 3D information into a large language model (LLM), which in turn generates a 2D SMILES string, while embedding a learnable encoding designed to preserve the integrity of the original 3D information, providing better structural information for the model. Additionally, we have designed an equivariant learning module to encompass representations of conformations and feature learning for conformational sampling. This framework aims to predict thermodynamic properties more accurately than learning from 2D topology alone, while providing faster computational speeds than conventional simulations. By combining machine learning and quantum chemistry, we pioneer efficient practical applications in the field of energy chemistry. Our model advances the integration of data-driven and physics-based modeling to unlock novel insights into carbon-based molecules.
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Affiliation(s)
- Haoyu Wang
- University of Shanghai for Science and Technology, Shanghai, China; School of Electronic and Electrical Engineering, Shanghai University of Engineering Science, Shanghai, China.
| | - Bin Chen
- University of Shanghai for Science and Technology, Shanghai, China; School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Hangling Sun
- Hengtu Imalligent Technology (Shanghai) Co., Ltd., Shanghai, China
| | - Yuxuan Zhang
- University of Shanghai for Science and Technology, Shanghai, China
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3
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Li H, Wang J, Warr GG, Atkin R. Effect of Potential on the Nanostructure Dynamics of Ethylammonium Nitrate at a Graphite Electrode. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306011. [PMID: 37806754 DOI: 10.1002/smll.202306011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/20/2023] [Indexed: 10/10/2023]
Abstract
Video-rate atomic force microscopy (AFM) is used to study the near-surface nanostructure dynamics of the ionic liquid ethylammonium nitrate (EAN) at a highly oriented pyrolytic graphite (HOPG) electrode as a function of potential in real-time for the first time. The effects of varying the surface potential and adding 10 wt% water on the nanostructure diffusion coefficient are probed. For both EAN and the 90 wt% EAN-water mixture, disk-like features ≈9 nm in diameter and 1 nm in height form above the Stern layer at all potentials. The nanostructure diffusion coefficient increases with potential (from OCP -0.5 V to OCP +0.5 V) and with added water. Nanostructure dynamics depends on both the magnitude and direction of the potential change. Upon switching the potential from OCP -0.5 V to OCP +0.5 V, a substantial increase in the diffusion coefficients is observed, likely due to the absence of solvophobic interactions between the nitrate (NO3 - ) anions and the ethylammonium (EA+ ) cations in the near-surface region. When the potential is reversed, EA+ is attracted to the Stern layer to replace NO3 - , but its movement is hindered by solvophobic attractions. The outcomes will aid applications, including electrochemical devices, catalysts, and lubricants.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Jianan Wang
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
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4
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Bou Tannous L, Simoes Santos M, Gong Z, Haumesser PH, Benayad A, Padua AAH, Steinberger A. Effect of Surface Chemistry on the Electrical Double Layer in a Long-Chain Ionic Liquid. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16785-16796. [PMID: 37970757 DOI: 10.1021/acs.langmuir.3c02123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Room temperature ionic liquids (ILs) can create a strong accumulation of charges at solid interfaces by forming a very thin and dense electrical double layer (EDL). The structure of this EDL has important consequences in numerous applications involving ILs, for example, in supercapacitors, sensors, and lubricants, by impacting the interfacial capacitance, the charge carrier density of semiconductors, as well as the frictional properties of the interfaces. We have studied the interfacial structure of a long chain imidazolium-based IL (1-octyl-3-methylimidazolium dicyanamide) on several substrates: mica, silica, silicon, and molybdenum disulfide (MoS2), using atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulations. We have observed 3 types of interfacial structures for the same IL, depending on the chemistry of the substrate and the water content, showing that the EDL structure is not an intrinsic property of the IL. We evidenced that at a low water content, neutral and apolar (thus hydrophobic) substrates promote a thin layer structure, where the ions are oriented parallel to the substrate and cations and anions are mixed in each layer. In contrast, a strongly charged (thus hydrophilic) substrate yields an extended structuration into several bilayers, while a heterogeneous layering with loose bilayer regions was observed on an intermediate polar and weakly charged substrate and on an apolar one at a high bulk water content. In the latter case, water contamination favors the formation of bilayer patches by promoting the segregation of the long chain IL into polar and apolar domains.
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Affiliation(s)
- Layla Bou Tannous
- Laboratoire de Chimie, École Normale Supérieure de Lyon, CNRS, 69364 Lyon, France
- CEA, Leti, Univ. Grenoble Alpes, F-38000 Grenoble, France
| | | | - Zheng Gong
- Laboratoire de Chimie, École Normale Supérieure de Lyon, CNRS, 69364 Lyon, France
| | | | - Anass Benayad
- CEA, Liten, Univ. Grenoble Alpes, F-38000 Grenoble, France
| | - Agilio A H Padua
- Laboratoire de Chimie, École Normale Supérieure de Lyon, CNRS, 69364 Lyon, France
| | - Audrey Steinberger
- Univ Lyon, ENS de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
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5
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Garvey CJ, Bryant SJ, Elbourne A, Hunt T, Kent B, Kreuzer M, Strobl M, Steitz R, Bryant G. Phase separation in a ternary DPPC/DOPC/POPC system with reducing hydration. J Colloid Interface Sci 2023; 638:719-732. [PMID: 36774881 DOI: 10.1016/j.jcis.2023.01.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/10/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
The maintenance of plasma membrane structure is vital for the viability of cells. Disruption of this structure can lead to cell death. One important example is the macroscopic phase separation observed during dehydration associated with desiccation and freezing, often leading to loss of permeability and cell death. It has previously been shown that the hybrid lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) can act as a line-active component in ternary lipid systems, inhibiting macroscopic phase separation and stabilising membrane microdomains in lipid vesicles [1]. The domain size is found to decrease with increasing POPC concentration until complete mixing is observed. However, no such studies have been carried out at reduced hydration. To examine if this phase separation is unique to vesicles in excess water, we have conducted studies on several binary and ternary model membrane systems at both reduced hydration ("powder" type samples and oriented membrane stacks) and in excess water (supported lipid bilayers) at 0.2 mol fraction POPC, in the range where microdomain stabilisation is reported. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) are used to map phase transition temperatures, with X-ray and neutron scattering providing details of the changes in lipid packing and phase information within these boundaries. Atomic force microscopy (AFM) is used to image bilayers on a substrate in excess water. In all cases, macroscopic phase separation was observed rather than microdomain formation at this molar ratio. Thus POPC does not stabilise microdomains under these conditions, regardless of the type of model membrane, hydration or temperature. Thus we conclude that the driving force for separation under these conditions overcomes any linactant effects of the hybrid lipid.
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Affiliation(s)
- Christopher J Garvey
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany.
| | | | - Aaron Elbourne
- School of Science, RMIT University, Melbourne, Australia
| | - Taavi Hunt
- School of Science, RMIT University, Melbourne, Australia
| | - Ben Kent
- Centre for Advanced Macromolecular Design, School of Chemistry, The University of New South Wales, Sydney 2052, Australia; Institute for Soft Matter and Functional Materials, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin, Germany
| | - Martin Kreuzer
- Institute for Soft Matter and Functional Materials, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin, Germany; ALBA Synchrotron, Barcelona, Spain
| | - Markus Strobl
- Institute for Soft Matter and Functional Materials, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin, Germany; Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Roland Steitz
- Institute for Soft Matter and Functional Materials, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin, Germany
| | - Gary Bryant
- School of Science, RMIT University, Melbourne, Australia.
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6
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Freeman JS, Mamme MH, Ustarroz J, Warr GG, Li H, Atkin R. Molecular Resolution Nanostructure and Dynamics of the Deep Eutectic Solvent-Graphite Interface as a Function of Potential. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2204993. [PMID: 36627266 DOI: 10.1002/smll.202204993] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Interest in deep eutectic solvents (DESs), particularly for electrochemical applications, has boomed in the past decade because they are more versatile than conventional electrolyte solutions and are low cost, renewable, and non-toxic. The molecular scale lateral nanostructures as a function of potential at the solid-liquid interface-critical design parameters for the use of DESs as electrochemical solvents-are yet to be revealed. In this work, in situ amplitude modulated atomic force microscopy complemented by molecular dynamics simulations is used to probe the Stern and near-surface layers of the archetypal and by far most studied DES, 1:2 choline chloride:urea (reline), at the highly orientated pyrolytic graphite surface as a function of potential, to reveal highly ordered lateral nanostructures with unprecedented molecular resolution. This detail allows identification of choline, chloride, and urea in the Stern layer on graphite, and in some cases their orientations. Images obtained after the potential is switched from negative to positive show the dynamics of the Stern layer response, revealing that several minutes are required to reach equilibrium. These results provide valuable insight into the nanostructure and dynamics of DESs at the solid-liquid interface, with implications for the rational design of DESs for interfacial applications.
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Affiliation(s)
- Justin S Freeman
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Mesfin Haile Mamme
- Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
| | - Jon Ustarroz
- Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, 1050, Belgium
- Chemistry of Surfaces, Interfaces and Nanomaterials (ChemSIN), Université Libre de Bruxelles, Boulevard du Triomphe 2, Brussels, 1050, Belgium
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
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7
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Kariuki R, Penman R, Bryant SJ, Orrell-Trigg R, Meftahi N, Crawford RJ, McConville CF, Bryant G, Voïtchovsky K, Conn CE, Christofferson AJ, Elbourne A. Behavior of Citrate-Capped Ultrasmall Gold Nanoparticles on a Supported Lipid Bilayer Interface at Atomic Resolution. ACS NANO 2022; 16:17179-17196. [PMID: 36121776 DOI: 10.1021/acsnano.2c07751] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nanomaterials have the potential to transform biological and biomedical research, with applications ranging from drug delivery and diagnostics to targeted interference of specific biological processes. Most existing research is aimed at developing nanomaterials for specific tasks such as enhanced biocellular internalization. However, fundamental aspects of the interactions between nanomaterials and biological systems, in particular, membranes, remain poorly understood. In this study, we provide detailed insights into the molecular mechanisms governing the interaction and evolution of one of the most common synthetic nanomaterials in contact with model phospholipid membranes. Using a combination of atomic force microscopy (AFM) and molecular dynamics (MD) simulations, we elucidate the precise mechanisms by which citrate-capped 5 nm gold nanoparticles (AuNPs) interact with supported lipid bilayers (SLBs) of pure fluid (DOPC) and pure gel-phase (DPPC) phospholipids. On fluid-phase DOPC membranes, the AuNPs adsorb and are progressively internalized as the citrate capping of the NPs is displaced by the surrounding lipids. AuNPs also interact with gel-phase DPPC membranes where they partially embed into the outer leaflet, locally disturbing the lipid organization. In both systems, the AuNPs cause holistic perturbations throughout the bilayers. AFM shows that the lateral diffusion of the particles is several orders of magnitude smaller than that of the lipid molecules, which creates some temporary scarring of the membrane surface. Our results reveal how functionalized AuNPs interact with differing biological membranes with mechanisms that could also have implications for cooperative membrane effects with other molecules.
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Affiliation(s)
- Rashad Kariuki
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Rowan Penman
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Saffron J Bryant
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Rebecca Orrell-Trigg
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Nastaran Meftahi
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Russell J Crawford
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Chris F McConville
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
- Deakin University, Geelong, VIC 3220, Australia
| | - Gary Bryant
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Kislon Voïtchovsky
- University of Durham, Physics Department, Durham DH1 3LE, United Kingdom
| | - Charlotte E Conn
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
| | - Andrew J Christofferson
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Aaron Elbourne
- School of Science, STEM College, RMIT University, Melbourne, VIC 3001, Australia
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8
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Panse KS, Wu H, Zhou S, Zhao F, Aluru NR, Zhang Y. Innermost Ion Association Configuration Is a Key Structural Descriptor of Ionic Liquids at Electrified Interfaces. J Phys Chem Lett 2022; 13:9464-9472. [PMID: 36198103 DOI: 10.1021/acs.jpclett.2c02768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The structure of electric double layers (EDLs) is crucial for all types of electrochemical processes. While in dilute solutions EDL structure can be approximately treated within the Gouy-Chapman-Stern regime, in highly ionic electrolytes the description of EDL has been largely elusive. Here we study the EDL structure of an ionic liquid on a series of crystalline electrodes. Through molecular dynamics (MD) simulations, we observe strong intermolecular interaction among cations and anions and propose that the cation-anion association structure at the innermost layer is a key descriptor of the EDL. Using our recently developed electrochemical 3D atomic force microscopy (EC-3D-AFM) technique, we confirm the theoretical prediction and further find that the width of the first EDL is an experimental gauge of the ion association structure in that layer. We expect such ion association descriptors to be broadly applicable to a large range of highly ionic electrolytes on various electrode surfaces.
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Affiliation(s)
- Kaustubh S Panse
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Haiyi Wu
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas78712, United States
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Shan Zhou
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Fujia Zhao
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
| | - Narayana R Aluru
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas78712, United States
- Oden Institute for Computational Engineering & Sciences, The University of Texas at Austin, Austin, Texas78712, United States
| | - Yingjie Zhang
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois61801, United States
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9
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Gregory KP, Elliott GR, Wanless EJ, Webber GB, Page AJ. A quantum chemical molecular dynamics repository of solvated ions. Sci Data 2022; 9:430. [PMID: 35864118 PMCID: PMC9304403 DOI: 10.1038/s41597-022-01527-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 06/30/2022] [Indexed: 12/29/2022] Open
Abstract
The importance of ion-solvent interactions in predicting specific ion effects in contexts ranging from viral activity through to electrolyte viscosity cannot be underestimated. Moreover, investigations of specific ion effects in nonaqueous systems, highly relevant to battery technologies, biochemical systems and colloid science, are severely limited by data deficiency. Here, we report IonSolvR – a collection of more than 3,000 distinct nanosecond-scale ab initio molecular dynamics simulations of ions in aqueous and non-aqueous solvent environments at varying effective concentrations. Density functional tight binding (DFTB) is used to detail the solvation structure of up to 55 solutes in 28 different protic and aprotic solvents. DFTB is a fast quantum chemical method, and as such enables us to bridge the gap between efficient computational scaling and maintaining accuracy, while using an internally-consistent simulation technique. We validate the database against experimental data and provide guidance for accessing individual IonSolvR records. Measurement(s) | solvation structure | Technology Type(s) | quantum chemistry computational method • Molecular Dynamics |
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Affiliation(s)
- Kasimir P Gregory
- Discipline of Chemistry, School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia.,Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT, 0200, Australia
| | - Gareth R Elliott
- Discipline of Chemistry, School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Erica J Wanless
- Discipline of Chemistry, School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Grant B Webber
- Discipline of Chemical Engineering, School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Alister J Page
- Discipline of Chemistry, School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia.
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10
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Chandrashekar A, Belardinelli P, Bessa MA, Staufer U, Alijani F. Quantifying nanoscale forces using machine learning in dynamic atomic force microscopy. NANOSCALE ADVANCES 2022; 4:2134-2143. [PMID: 35601812 PMCID: PMC9063738 DOI: 10.1039/d2na00011c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/01/2022] [Indexed: 05/14/2023]
Abstract
Dynamic atomic force microscopy (AFM) is a key platform that enables topological and nanomechanical characterization of novel materials. This is achieved by linking the nanoscale forces that exist between the AFM tip and the sample to specific mathematical functions through modeling. However, the main challenge in dynamic AFM is to quantify these nanoscale forces without the use of complex models that are routinely used to explain the physics of tip-sample interaction. Here, we make use of machine learning and data science to characterize tip-sample forces purely from experimental data with sub-microsecond resolution. Our machine learning approach is first trained on standard AFM models and then showcased experimentally on a polymer blend of polystyrene (PS) and low density polyethylene (LDPE) sample. Using this algorithm we probe the complex physics of tip-sample contact in polymers, estimate elasticity, and provide insight into energy dissipation during contact. Our study opens a new route in dynamic AFM characterization where machine learning can be combined with experimental methodologies to probe transient processes involved in phase transformation as well as complex chemical and biological phenomena in real-time.
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Affiliation(s)
| | | | - Miguel A Bessa
- Materials Science and Engineering, TU Delft Delft The Netherlands
| | - Urs Staufer
- Precision and Microsystems Engineering, TU Delft Delft The Netherlands
| | - Farbod Alijani
- Precision and Microsystems Engineering, TU Delft Delft The Netherlands
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11
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Bulk and interfacial nanostructure and properties in deep eutectic solvents: Current perspectives and future directions. J Colloid Interface Sci 2021; 608:2430-2454. [PMID: 34785053 DOI: 10.1016/j.jcis.2021.10.163] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/25/2022]
Abstract
Deep eutectic solvents (DESs) are a tailorable class of solvents that are rapidly gaining scientific and industrial interest. This is because they are distinct from conventional molecular solvents, inherently tuneable via careful selection of constituents, and possess many attractive properties for applications, including catalysis, chemical extraction, reaction media, novel lubricants, materials chemistry, and electrochemistry. DESs are a class of solvents composed solely of hydrogen bond donors and acceptors with a melting point lower than the individual components and are often fluidic at room temperature. A unique feature of DESs is that they possess distinct bulk liquid and interfacial nanostructure, which results from intra- and inter-molecular interactions, including coulomb forces, hydrogen bonding, van der Waals interactions, electrostatics, dispersion forces, and apolar-polar segregation. This nanostructure manifests as preferential spatial arrangements of the different species, and exists over several length scales, from molecular- to nano- and meso-scales. The physicochemical properties of DESs are dictated by structure-property relationships; however, there is a significant gap in our understanding of the underlying factors which govern their solvent properties. This is a major limitation of DES-based technologies, as nanostructure can significantly influence physical properties and thus potential applications. This perspective provides an overview of the current state of knowledge of DES nanostructure, both in the bulk liquid and at solid interfaces. We provide definitions which clearly distinguish DESs as a unique solvent class, rather than a subset of ILs. An appraisal of recent work provides hints towards trends in structure-property relationships, while also highlighting inconsistencies within the literature suggesting new research directions for the field. It is hoped that this review will provide insight into DES nanostructure, their potential applications, and development of a robust framework for systematic investigation moving forward.
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12
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Lu Y, Xu Y, Lu L, Xu Z, Liu H. Interfacial interactions and structures of protic ionic liquids on a graphite surface: A first-principles study and comparison with aprotic ionic liquids. Phys Chem Chem Phys 2021; 23:18338-18348. [PMID: 34612375 DOI: 10.1039/d1cp02100a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protic ionic liquids (PILs) have currently been indicated as promising alternative electrolytes in electrical storage devices, such as lithium-ion batteries and supercapacitors. However, compared with the well-studied aprotic ionic liquids (AILs), the knowledge of the interface between PILs and electrode material surfaces is very rare to date. In this work, the adsorption behaviors of three groups of PILs, i.e. pyrrolidinium-based, imidazolium-based, and ammonium-based, on graphite was systematically investigated using first-principles calculations. The corresponding AILs were also taken into account for comparison. The adsorption mechanism of these ILs on the surface is controlled by the interplay of strong electrostatic interactions between adsorbed ions, weak vdW forces between ILs and substrate, and many aromatic interactions including π-π stacking and C-H/N-Hπ contacts. PILs do show quite different preferential interfacial interactions and structures on the graphite surface with respect to AILs, arising mainly from the anion-substrate interactions. Particularly, proton transfer takes place in the PILs consisting of the imidazolium/ammonium cation and the nitrate anion in the gas phase, but it tends to be attenuated or even disappears on graphite caused by interfacial interactions.
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Affiliation(s)
- Yunxiang Lu
- Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China.
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13
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Elbourne A, Meftahi N, Greaves TL, McConville CF, Bryant G, Bryant SJ, Christofferson AJ. Nanostructure of a deep eutectic solvent at solid interfaces. J Colloid Interface Sci 2021; 591:38-51. [PMID: 33592524 DOI: 10.1016/j.jcis.2021.01.089] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
HYPOTHESIS Deep eutectic solvents (DESs) are an attractive class of tunable solvents. However, their uptake for relevant applications has been limited due to a lack of detailed information on their structure-property relationships, both in the bulk and at interfaces. The lateral nanostructure of the DES-solid interfaces is likely to be more complex than previously reported and requires detailed, high-resolution investigation. EXPERIMENTS We employ a combination of high-resolution amplitude-modulated atomic force microscopy and molecular dynamics simulations to elucidate the lateral nanostructure of a DES at the solid-liquid interface. Specifically, the lateral and near-surface nanostructure of the DES choline chloride:glycerol is probed at the mica and highly-ordered pyrolytic graphite interfaces. FINDINGS The lateral nanostructure of the DES-solid interface is heterogeneous and well-ordered in both systems. At the mica interface, the DES is strongly ordered via polar interactions. The adsorbed layer has a distinct rhomboidal symmetry with a repeat spacing of ~0.9 nm comprising all DES species. At the highly ordered pyrolytic graphite interface, the adsorbed layer appears distinctly different, forming an apolor-driven row-like structure with a repeat spacing of ~0.6 nm, which largely excludes the chloride ion. The interfacial nanostructure results from a delicate balance of substrate templating, liquid-liquid interactions, species surface affinity, and packing constraints of cations, anions, and molecular components within the DES. For both systems, distinct near-surface nanostructural layering is observed, which becomes more pronounced close to the substrate. The surface nanostructures elucidated here significantly expand our understanding of DES interfacial behavior and will enhance the optimization of DES systems for surface-based applications.
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Affiliation(s)
- Aaron Elbourne
- School of Science, RMIT University, Melbourne, VIC 3000, Australia.
| | - Nastaran Meftahi
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Tamar L Greaves
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Christopher F McConville
- School of Science, RMIT University, Melbourne, VIC 3000, Australia; Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia
| | - Gary Bryant
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Saffron J Bryant
- School of Science, RMIT University, Melbourne, VIC 3000, Australia.
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14
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Meusel M, Lexow M, Gezmis A, Bayer A, Maier F, Steinrück HP. Growth of Multilayers of Ionic Liquids on Au(111) Investigated by Atomic Force Microscopy in Ultrahigh Vacuum. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13670-13681. [PMID: 33156635 PMCID: PMC7676296 DOI: 10.1021/acs.langmuir.0c02596] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Understanding the growth of ultrathin films of ionic liquids (ILs) on metal surfaces is of highest relevance for a variety of applications. We present a detailed study of the growth of the wetting layer and successive multilayers of 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im][Tf2N]) on Au(111). By atomic force microscopy (AFM) in ultrahigh vacuum, we follow the temperature-dependent behavior between 110 and 300 K at defined coverages. We initially observe the formation of a wetting layer with a thickness of ∼0.37 nm with anions and cations arranged in a checkerboard structure. Stable AFM imaging up to 280 K allows us to follow the IL growing on top of the wetting layer in bilayers with an average thickness of ∼0.71 nm, that is, double the height of the wetting layer, in a bilayer-by-bilayer fashion. This growth behavior is independently confirmed from the surface morphology, as deduced from AFM and angle-resolved X-ray photoelectron spectroscopy. High-resolution AFM images at 110 K allow for identifying the molecular surface structure of the bilayers as a striped phase, which is one of the phases also seen for the wetting layer (Meusel, M.; Lexow, M.; Gezmis, A.; Schotz, S.; Wagner, M.; Bayer, A.; Maier, F.; Steinrück, H. P. Atomic Force and Scanning Tunneling Microscopy of Ordered Ionic Liquid Wetting Layers from 110 K up to Room Temperature. ACS Nano 2020, 14, 9000-9010).
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Affiliation(s)
- Manuel Meusel
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Matthias Lexow
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Afra Gezmis
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Andreas Bayer
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Florian Maier
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische
Chemie II, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
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15
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Bakulina OD, Ivanov MY, Prikhod'ko SA, Pylaeva S, Zaytseva IV, Surovtsev NV, Adonin NY, Fedin MV. Nanocage formation and structural anomalies in imidazolium ionic liquid glasses governed by alkyl chains of cations. NANOSCALE 2020; 12:19982-19991. [PMID: 32996529 DOI: 10.1039/d0nr06065h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intriguing nanostructuring anomalies have been recently observed in imidazolium ionic liquids (ILs) near their glass transition points, where local density around a nanocaged solute progressively grows up with temperature. Herewith, we for the first time demonstrate experimentally and theoretically, that these anomalies are governed by alkyl chains of cations and crucially depend on their length. Electron Paramagnetic Resonance (EPR) spectroscopy on a series of ILs [Cnmim]BF4 (n = 0-12) shows that only the chains with n = 3-10 favor anomaly. Moreover, remarkable even vs. odd n peculiarities were systematically observed. Finally, similar anomaly was for the first time observed for a non-IL glass of dibutyl phthalate, which structurally mimics cations of imidazolium ILs. Therefore, such anomalous density behavior in a glassy state nanocage goes far beyond ILs and proves to be a more general phenomenon, which can be structurally tuned and rationally adjusted for various potential applications in nanoscale materials.
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Affiliation(s)
- Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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16
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Meusel M, Lexow M, Gezmis A, Schötz S, Wagner M, Bayer A, Maier F, Steinrück HP. Atomic Force and Scanning Tunneling Microscopy of Ordered Ionic Liquid Wetting Layers from 110 K up to Room Temperature. ACS NANO 2020; 14:9000-9010. [PMID: 32609482 PMCID: PMC7391993 DOI: 10.1021/acsnano.0c03841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/01/2020] [Indexed: 05/31/2023]
Abstract
Ionic liquids (ILs) are used as ultrathin films in many applications. We studied the nanoscale arrangement within the first layer of 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im] [Tf2N]) on Au(111) between 400 and 110 K in ultrahigh vacuum by scanning tunneling and noncontact atomic force microscopy with molecular resolution. Compared to earlier studies on similar ILs, a different behavior is observed, which we attribute to the small size and symmetrical shape of the cation: (a) In both AFM and STM only the anions are imaged; (b) only long-range-ordered but no amorphous phases are observed; (c) the hexagonal room-temperature phase melts 30-50 K above the IL's bulk melting point; (d) at 110 K, striped and hexagonal superstructures with two and three ion pairs per unit cell, respectively, are found. AFM turned out to be more stable at higher temperature, while STM revealed more details at low temperature.
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Affiliation(s)
- Manuel Meusel
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Matthias Lexow
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Afra Gezmis
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Simon Schötz
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Margareta Wagner
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
- Institute
of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria
| | - Andreas Bayer
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Florian Maier
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl
für Physikalische Chemie II, Universität
Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
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17
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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18
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An R, Qiu X, Shah FU, Riehemann K, Fuchs H. Controlling the nanoscale friction by layered ionic liquid films. Phys Chem Chem Phys 2020; 22:14941-14952. [PMID: 32588010 DOI: 10.1039/d0cp02146f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nanofriction coefficient of ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), on the surfaces of mica and graphite was investigated using atomic force microscopy (AFM). A pronounced layered spatial distribution was found in the IL film formed on the solid substrates and can be divided into 3 well distinguishable regions exhibiting different physical properties with increasing distance from the substrate. We found that the friction coefficient (μ) increases monotonically as the layering thickness decreases, no matter what the thickness of the bulk IL is. This suggests that the layering assembled IL at solid surfaces is more important than the bulk phase in determining the magnitude of the nanoscale friction. The increase in the friction coefficient as the layering thickness decreases is most likely attributed to the assembled ordered IL layers closer to the substrate surfaces having a greater activation barrier for unlocking the surfaces to allow shear.
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Affiliation(s)
- Rong An
- Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China. and Center for Nanotechnology (CeNTech), Institute of Physics, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Xiuhua Qiu
- Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, SE 971 87 Luleå, Sweden
| | - Kristina Riehemann
- Center for Nanotechnology (CeNTech), Institute of Physics, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Harald Fuchs
- Herbert Gleiter Institute of Nanoscience, Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China. and Center for Nanotechnology (CeNTech), Institute of Physics, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
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19
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Li H, Niemann T, Ludwig R, Atkin R. Effect of Hydrogen Bonding between Ions of Like Charge on the Boundary Layer Friction of Hydroxy-Functionalized Ionic Liquids. J Phys Chem Lett 2020; 11:3905-3910. [PMID: 32338913 DOI: 10.1021/acs.jpclett.0c00689] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atomic force microscopy has been used to measure the lubricity of a series of ionic liquids (ILs) at mica surfaces in the boundary friction regime. A previously unreported cation bilayer structure is detected at the IL-mica interface due to the formation of H-bonds between the hydroxy-functionalized cations [(c-c) H-bonds], which enhances the ordering of the ions in the boundary layer and improves the lubrication. The strength of the cation bilayer structure is controlled by altering the strength of (c-c) H-bonding via changes in the hydroxyalkyl chain length, the cation charge polarizability, and the coordination strength of the anions. This reveals a new means of controlling IL boundary nanostructure via H-bonding between ions of the same charge, which can impact diverse applications, including surface catalysis, particle stability, electrochemistry, etc.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Strasse 29a, 18059 Rostock, Germany
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
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20
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Bhattacharjee S, Khan S. The wetting behavior of aqueous imidazolium based ionic liquids: a molecular dynamics study. Phys Chem Chem Phys 2020; 22:8595-8605. [PMID: 32255456 DOI: 10.1039/d0cp00143k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aqueous ionic liquids are of particular interest due to their tunability of physical and chemical properties and a deeper understanding of their structure-property relationship is desired. Molecular dynamics (MD) simulations were conducted to study the wetting behavior of aqueous imidazolium-based ionic liquids (ILs), consisting of a 1-ethyl-3-methylimidazolium [EMIM]+ cation and either a hydrophilic boron tetrafluoride [BF4]- or a hydrophobic bis(trifluoromethylsulfonyl)imide [NTF2]- anion mixed in water. To understand the effect of anion and concentration of ILs at the graphite solid-liquid interface, wettability studies were performed with IL concentrations from 0-50 wt%. The contact angle of aqueous IL droplets decreases with increasing IL concentration. Droplet characteristics near the surface were investigated by profiling the density perpendicular (z-direction) and horizontal (r-direction) to the graphite sheet; this was further quantified by an orientation order parameter. Due to the preferred adsorption of ILs, water depletes near the surface as IL concentration increases. The hydrophobic [NTF2]- anion forces the IL toward the interface from the bulk, whereas the hydrophilic [BF4]- anion causes the IL to remain in the bulk of the droplet. Differences in water-anion hydrogen bonding, the nature of the anions, and their interfacial tensions are crucial factors in the wetting behavior of aqueous ionic liquids.
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Affiliation(s)
- Sanchari Bhattacharjee
- Department of Chemical and Biochemical Engineering, Indian Institute of Technology Patna, 801103, India.
| | - Sandip Khan
- Department of Chemical and Biochemical Engineering, Indian Institute of Technology Patna, 801103, India.
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21
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Niemann T, Li H, Warr GG, Ludwig R, Atkin R. Influence of Hydrogen Bonding between Ions of Like Charge on the Ionic Liquid Interfacial Structure at a Mica Surface. J Phys Chem Lett 2019; 10:7368-7373. [PMID: 31713427 DOI: 10.1021/acs.jpclett.9b03007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ionic liquids (ILs) have attracted increasing interest in science and technology because of their remarkable properties, which can be tuned via varying ion structures to control the relative strengths of Coulomb interactions, hydrogen bonding (H-bonding), and dispersion forces. Here we use atomic force microscopy to probe the interfacial nanostructures of hydroxy functionalized ILs at negatively charged mica surfaces. H-bonding between hydroxy functionalized cations (c-c) produces cation clusters and a stronger interfacial nanostructure. H-bond stabilized cation clusters form despite opposing electrostatic repulsions between charge groups, cation-anion (c-a) electrostatic attractions, and (c-a) H-bonds. Comparison of ILs with and without OH functionalized cations shows directional H-bonding enhances interfacial structure more strongly than the dispersion forces between alkyl groups. These findings reveal a new means of controlling IL interfacial nanostructure via H-bonding between like-charged ions, which impact diverse areas including electrochemical charge storage (batteries and catalysis), electrodeposition, lubrication, etc.
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Affiliation(s)
- Thomas Niemann
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 18059 Rostock , Germany
- Department LL&M , University of Rostock , Albert-Einstein-Str. 25 , 18059 Rostock , Germany
| | - Hua Li
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute , The University of Sydney , Camperdown , NSW 2006 , Australia
| | - Ralf Ludwig
- Institut für Chemie, Abteilung für Physikalische Chemie , Universität Rostock , Dr.-Lorenz-Weg 2 , 18059 Rostock , Germany
- Department LL&M , University of Rostock , Albert-Einstein-Str. 25 , 18059 Rostock , Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V. , Albert-Einstein-Str. 29a , 18059 Rostock , Germany
| | - Rob Atkin
- School of Molecular Sciences , The University of Western Australia , Perth , Western Australia 6009 , Australia
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22
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Vučemilović-Alagić N, Banhatti RD, Stepić R, Wick CR, Berger D, Gaimann MU, Baer A, Harting J, Smith DM, Smith AS. Insights from molecular dynamics simulations on structural organization and diffusive dynamics of an ionic liquid at solid and vacuum interfaces. J Colloid Interface Sci 2019; 553:350-363. [DOI: 10.1016/j.jcis.2019.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
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23
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Häckl K, Li H, Aldous IM, Tsui T, Kunz W, Abbott AP, Warr GG, Atkin R. Potential Dependence of Surfactant Adsorption at the Graphite Electrode/Deep Eutectic Solvent Interface. J Phys Chem Lett 2019; 10:5331-5337. [PMID: 31430167 DOI: 10.1021/acs.jpclett.9b01968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Atomic force microscopy and cyclic voltammetry are used to probe how ionic surfactant adsorbed layer structure affects redox processes at deep eutectic solvent (DES)/graphite interfaces. Unlike its behavior in water, sodium dodecyl sulfate (SDS) in DESs only adsorbs as a complete layer of hemicylindrical hemimicelles far above its critical micelle concentration (CMC). Near the CMC it forms a tail-to-tail monolayer at open-circuit potential (OCP) and positive potentials, and it desorbs at negative potentials. In contrast, cetyltrimethylammonium bromide (CTAB) adsorbs as hemimicelles at low concentrations and remains adsorbed at both positive and negative potentials. The SDS horizontal monolayer has little overall effect on redox processes at the graphite interface, but hemimicelles form an effective and stable barrier. The stronger solvophobic interactions between the C16 versus C12 alkyl chains in the DES allow CTAB to self-assemble into a robust coating at low concentrations and illustrate how the structure of the DES/electrode interface and electrochemical response can be engineered by controlling surfactant structure.
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Affiliation(s)
- Katharina Häckl
- Institute of Physical and Theoretical Chemistry , University of Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
- School of Molecular Sciences , The University of Western Australia , 35 Stirling Highway , Perth , WA 6009 , Australia
| | - Hua Li
- School of Molecular Sciences , The University of Western Australia , 35 Stirling Highway , Perth , WA 6009 , Australia
- Centre for Microscopy, Characterisation and Analysis , The University of Western Australia , 35 Stirling Highway , Perth , WA 6009 , Australia
| | - Iain M Aldous
- Materials Centre, Department of Chemistry , University of Leicester , Leicester LE1 7RH , U.K
| | - Terrence Tsui
- School of Molecular Sciences , The University of Western Australia , 35 Stirling Highway , Perth , WA 6009 , Australia
| | - Werner Kunz
- Institute of Physical and Theoretical Chemistry , University of Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | - Andrew P Abbott
- Materials Centre, Department of Chemistry , University of Leicester , Leicester LE1 7RH , U.K
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute , The University of Sydney , Camperdown , NSW 2006 , Australia
| | - Rob Atkin
- School of Molecular Sciences , The University of Western Australia , 35 Stirling Highway , Perth , WA 6009 , Australia
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24
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Abstract
Ionic liquids have become of significant relevance in chemistry, as they can serve as environmentally-friendly solvents, electrolytes, and lubricants with bespoke properties. In particular for electrochemical applications, an understanding of the interface structure between the ionic liquid and an electrified interface is needed to model and optimize the reactions taking place on the solid surface. As with ionic liquids, the interplay between electrostatic forces and steric effects leads to an intrinsic heterogeneity, as the structure of the ionic liquid above an electrified interface cannot be described by the classical electrical double layer model. Instead, a layered solvation layer is present with a structure that depends on the material combination of the ionic liquid and substrate. In order to experimentally monitor this structure, atomic force spectroscopy (AFS) has become the method of choice. By measuring the force acting on a sharp microfabricated tip while approaching the surface in an ionic liquid, it has become possible to map the solvation layers with sub-nanometer resolution. In this review, we provide an overview of the AFS studies on ionic liquids published in recent years that illustrate how the interface is formed and how it can be modified by applying electrical potential or by adding impurities and solvents.
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25
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Docampo-Álvarez B, Gómez-González V, Cabeza O, Ivaništšev VB, Gallego LJ, Varela LM. Molecular dynamics simulations of novel electrolytes based on mixtures of protic and aprotic ionic liquids at the electrochemical interface: Structure and capacitance of the electric double layer. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Stefanovic R, Webber GB, Page AJ. Polymer solvation in choline chloride deep eutectic solvents modulated by the hydrogen bond donor. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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27
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Velpula G, Phillipson R, Lian JX, Cornil D, Walke P, Verguts K, Brems S, Uji-I H, De Gendt S, Beljonne D, Lazzaroni R, Mali KS, De Feyter S. Graphene Meets Ionic Liquids: Fermi Level Engineering via Electrostatic Forces. ACS NANO 2019; 13:3512-3521. [PMID: 30860809 DOI: 10.1021/acsnano.8b09768] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Graphene-based two-dimensional (2D) materials are promising candidates for a number of different energy applications. A particularly interesting one is in next generation supercapacitors, where graphene is being explored as an electrode material in combination with room temperature ionic liquids (ILs) as electrolytes. Because the amount of energy that can be stored in such supercapacitors critically depends on the electrode-electrolyte interface, there is considerable interest in understanding the structure and properties of the graphene/IL interface. Here, we report the changes in the properties of graphene upon adsorption of a homologous series of alkyl imidazolium tetrafluoroborate ILs using a combination of experimental and theoretical tools. Raman spectroscopy reveals that these ILs cause n-type doping of graphene, and the magnitude of doping increases with increasing cation chain length despite the expected decrease in the density of surface-adsorbed ions. Molecular modeling simulations show that doping originates from the changes in the electrostatic potential at the graphene/IL interface. The findings described here represent an important step in developing a comprehensive understanding of the graphene/IL interface.
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Affiliation(s)
- Gangamallaiah Velpula
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
| | - Roald Phillipson
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
| | - Jian Xiang Lian
- Laboratory for Chemistry of Novel Materials , University of Mons , Place du Parc 20 , 7000 Mons , Belgium
| | - David Cornil
- Laboratory for Chemistry of Novel Materials , University of Mons , Place du Parc 20 , 7000 Mons , Belgium
| | - Peter Walke
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
| | - Ken Verguts
- Molecular Design and Synthesis, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
- imec vzw , Kapeldreef 75 , B-3001 Leuven , Belgium
| | - Steven Brems
- imec vzw , Kapeldreef 75 , B-3001 Leuven , Belgium
| | - Hiroshi Uji-I
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
- RIES , Hokkaido University , N20 W10 , Kita-Ward, Sapporo 001-0020 , Japan
| | - Stefan De Gendt
- Molecular Design and Synthesis, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
- imec vzw , Kapeldreef 75 , B-3001 Leuven , Belgium
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials , University of Mons , Place du Parc 20 , 7000 Mons , Belgium
| | - Roberto Lazzaroni
- Laboratory for Chemistry of Novel Materials , University of Mons , Place du Parc 20 , 7000 Mons , Belgium
| | - Kunal S Mali
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
| | - Steven De Feyter
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan, 200F , B-3001 Leuven , Belgium
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28
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Elbourne A, Chapman J, Gelmi A, Cozzolino D, Crawford RJ, Truong VK. Bacterial-nanostructure interactions: The role of cell elasticity and adhesion forces. J Colloid Interface Sci 2019; 546:192-210. [PMID: 30921674 DOI: 10.1016/j.jcis.2019.03.050] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 02/07/2023]
Abstract
The attachment of single-celled organisms, namely bacteria and fungi, to abiotic surfaces is of great interest to both the scientific and medical communities. This is because the interaction of such cells has important implications in a range of areas, including biofilm formation, biofouling, antimicrobial surface technologies, and bio-nanotechnologies, as well as infection development, control, and mitigation. While central to many biological phenomena, the factors which govern microbial surface attachment are still not fully understood. This lack of understanding is a direct consequence of the complex nature of cell-surface interactions, which can involve both specific and non-specific interactions. For applications involving micro- and nano-structured surfaces, developing an understanding of such phenomenon is further complicated by the diverse nature of surface architectures, surface chemistry, variation in cellular physiology, and the intended technological output. These factors are extremely important to understand in the emerging field of antibacterial nanostructured surfaces. The aim of this perspective is to re-frame the discussion surrounding the mechanism of nanostructured-microbial surface interactions. Broadly, the article reviews our current understanding of these phenomena, while highlighting the knowledge gaps surrounding the adhesive forces which govern bacterial-nanostructure interactions and the role of cell membrane rigidity in modulating surface activity. The roles of surface charge, cell rigidity, and cell-surface adhesion force in bacterial-surface adsorption are discussed in detail. Presently, most studies have overlooked these areas, which has left many questions unanswered. Further, this perspective article highlights the numerous experimental issues and misinterpretations which surround current studies of antibacterial nanostructured surfaces.
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Affiliation(s)
- Aaron Elbourne
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia.
| | - James Chapman
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - Amy Gelmi
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia
| | - Daniel Cozzolino
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia
| | - Russell J Crawford
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - Vi Khanh Truong
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
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29
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Elbourne A, Dupont MF, Collett S, Truong VK, Xu X, Vrancken N, Baulin V, Ivanova EP, Crawford RJ. Imaging the air-water interface: Characterising biomimetic and natural hydrophobic surfaces using in situ atomic force microscopy. J Colloid Interface Sci 2019; 536:363-371. [DOI: 10.1016/j.jcis.2018.10.059] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 12/30/2022]
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30
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Hammond OS, Li H, Westermann C, Al-Murshedi AYM, Endres F, Abbott AP, Warr GG, Edler KJ, Atkin R. Nanostructure of the deep eutectic solvent/platinum electrode interface as a function of potential and water content. NANOSCALE HORIZONS 2019; 4:158-168. [PMID: 32254151 DOI: 10.1039/c8nh00272j] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interfacial nanostructure of the three most widely-studied Deep Eutectic Solvents (DESs), choline chloride:urea (ChCl:Urea), choline chloride:ethylene glycol (ChCl:EG), and choline chloride:glycerol (ChCl:Gly) at a Pt(111) electrode has been studied as a function of applied potential and water content up to 50 wt%. Contact mode atomic force microscope (AFM) force-distance curves reveal that for all three DESs, addition of water increases the interfacial nanostructure up to ∼40 wt%, after which it decreases. This differs starkly from ionic liquids, where addition of small amounts of water rapidly decreases the interfacial nanostructure. For the pure DESs, only one interfacial layer is measured at OCP at 0.5 nm, which increases to 3 to 6 layers extending ∼5 nm from the surface at 40 or 50 wt% water. Application of a potential of ±0.25 V to the Pt electrode for the pure DESs increases the number of near surface layers to 3. However, when water is present the applied potential attenuates the steps in the force curve, which are replaced by a short-range exponential decay. This change was most pronounced for ChCl:EG with 30 wt% or 50 wt% water, so this system was probed using cyclic voltammetry, which confirms the interfacial nanostructure is akin to a salt solution.
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Affiliation(s)
- Oliver S Hammond
- Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath BA2 7AY, UK
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31
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Panhwar GM, Mysyk R, Rojo T, Shaikhutdinov S, Bondarchuk O. Electrowetting of Ionic Liquid on Graphite: Probing via in Situ Electrochemical X-ray Photoelectron Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14528-14536. [PMID: 30412414 DOI: 10.1021/acs.langmuir.8b02900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thin films of ionic liquid 1-ethyl-3-methylimidazolium bis(fluoromethylsulfonyl)imide ([EMIm][FSI]) vapor-deposited on highly oriented pyrographite (HOPG) were studied by X-ray photoelectron spectroscopy and atomic force microscopy. The results revealed a reversible morphological transition from a "drop-on-layer" structure to a "flat-layer" structure at positive, and not at negative, polarization. The effect is rationalized in terms of electric-field-induced reduction of the liquid-solid transition temperature in the ionic liquid film, when its thickness is comparable to the charge screening length. The observed bias asymmetry of [EMIm][FSI] electrowetting on HOPG is tentatively explained by the bilayer structure at the interface driven by the affinity of the imidazolium ring to the HOPG surface.
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Affiliation(s)
- Ghulam M Panhwar
- CIC Energigune , Parque Tecnológico de Alava , c/A. Einstein 48 , 01510 Miñano , Alava , Spain
| | - Roman Mysyk
- CIC Energigune , Parque Tecnológico de Alava , c/A. Einstein 48 , 01510 Miñano , Alava , Spain
| | - Teófilo Rojo
- CIC Energigune , Parque Tecnológico de Alava , c/A. Einstein 48 , 01510 Miñano , Alava , Spain
| | - Shamil Shaikhutdinov
- Abteilung Chemische Physik , Fritz-Haber-Institut der Max-Planck-Gesellschaft , Faradayweg 4-6 , 14195 Berlin , Germany
| | - Oleksandr Bondarchuk
- CIC Energigune , Parque Tecnológico de Alava , c/A. Einstein 48 , 01510 Miñano , Alava , Spain
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32
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Maruyama S, Prastiawan IBH, Toyabe K, Higuchi Y, Koganezawa T, Kubo M, Matsumoto Y. Ionic Conductivity in Ionic Liquid Nano Thin Films. ACS NANO 2018; 12:10509-10517. [PMID: 30199622 DOI: 10.1021/acsnano.8b06386] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thin film approaches are powerful methods for gaining a nanoscale understanding of interfacial ionic liquids (ILs) in the vicinity of solids. These approaches are used to directly elucidate the interfacial contributions to the physical properties of ILs as nanoscale thin films have significant proportions of the surface or interface region with respect to their total volume. Here, we report the growth of a uniform [emim][TFSA] thin film ionic liquid on a chemically modified, well-wettable sapphire, thereby allowing the in situ measurement of its ionic conductivity on the nanoscale. We observed the thickness-dependent behavior of the ionic conductivity, which gradually decreased especially when the thickness was less than 10 nm, and found it to be quantitatively analyzed well by using an empirical two-layer model. The molecular dynamics (MD) simulations show that the thickness-dependent ionic conductivity originates from the solid-like structuring of the IL near the substrate, reproducing a thickness-dependent ionic conductivity. The MD simulation results suggest that the thickness of the low conductivity region determined in the two-layer model should roughly correspond to the thickness of the solid-like structuring of the IL near the substrate.
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Affiliation(s)
- Shingo Maruyama
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | | | - Kaho Toyabe
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | - Yuji Higuchi
- Institute for Materials Research , Tohoku University , Sendai 980-8577 , Japan
| | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI) , SPring-8, 1-1-1 Kouto , Sayo , Hyogo 679-5198 , Japan
| | - Momoji Kubo
- Institute for Materials Research , Tohoku University , Sendai 980-8577 , Japan
| | - Yuji Matsumoto
- Department of Applied Chemistry, School of Engineering , Tohoku University , Sendai 980-8579 , Japan
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33
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Mitchell I, Aradi B, Page AJ. Density functional tight binding-based free energy simulations in the DFTB+ program. J Comput Chem 2018; 39:2452-2458. [DOI: 10.1002/jcc.25583] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/14/2018] [Accepted: 08/15/2018] [Indexed: 01/11/2023]
Affiliation(s)
- Izaac Mitchell
- School of Environmental and Life Sciences, University of Newcastle
| | - Bálint Aradi
- Bremen Center for Computational Materials Science, University of Bremen
| | - Alister J. Page
- School of Environmental and Life Sciences, University of Newcastle
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34
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Hartkamp R, Biance AL, Fu L, Dufrêche JF, Bonhomme O, Joly L. Measuring surface charge: Why experimental characterization and molecular modeling should be coupled. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.08.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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35
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Torkzadeh M, Moosavi M. A combined molecular dynamics simulation and quantum mechanics study on the physisorption of biodegradable CBNAILs on h-BN nanosheets. J Chem Phys 2018; 149:074704. [DOI: 10.1063/1.5039476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
| | - Majid Moosavi
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran
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36
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Stefanovic R, Webber GB, Page AJ. Nanostructure of propylammonium nitrate in the presence of poly(ethylene oxide) and halide salts. J Chem Phys 2018; 148:193826. [DOI: 10.1063/1.5012801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Ryan Stefanovic
- Priority Research Centre for Particle Processing and Transport, Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan, NSW 2308, Australia
- Priority Research Centre for Frontier Energy Technologies and Utilisation, Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Grant B. Webber
- Priority Research Centre for Particle Processing and Transport, Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Alister J. Page
- Priority Research Centre for Frontier Energy Technologies and Utilisation, Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan, NSW 2308, Australia
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37
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Waite SL, Li H, Page AJ. NO2 Solvation Structure in Choline Chloride Deep Eutectic Solvents—The Role of the Hydrogen Bond Donor. J Phys Chem B 2018; 122:4336-4344. [DOI: 10.1021/acs.jpcb.8b01508] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Simone L. Waite
- School of Environmental & Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Hua Li
- School of Environmental & Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Alister J. Page
- School of Environmental & Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia
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38
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Insight into the Electrical Double Layer of an Ionic Liquid on Graphene. Sci Rep 2017; 7:4225. [PMID: 28652593 PMCID: PMC5484676 DOI: 10.1038/s41598-017-04576-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/24/2017] [Indexed: 11/14/2022] Open
Abstract
Graphene is a promising next-generation conducting material with the potential to replace traditional electrode materials in supercapacitors. Since energy storage in supercapacitors relies on the electrolyte-electrode interface, here we elucidate the interfacial subnanometer structure of a single component liquid composed solely of cations and anions – an ionic liquid- on electrified graphene. We study the effect of applied potential on the interaction between graphene and a silicon tip in an ionic liquid and describe it within the framework of the Derjaguin-Landau-Verwey-Overbeck (DLVO) theory. The energy is stored in an electrical double layer composed of an extended Stern layer, which consists of multiple ion layers over ~2 nanometers, beyond which a diffuse layer forms to compensate the applied potential on graphene. The electrical double layer significantly responds to the applied potential, and it shows the transition from overscreening to crowding of counterions at the interface at the highest applied potentials. It is proposed that surface charging occurs through the adsorption of the imidazolium cation to unbiased graphene (likely due to π-π interactions) and that the surface potential is better compensated when counterion crowding happens. This study scrutinizes the electrified graphene-ionic liquid interface, with implications not only in the field of energy storage, but also in lubrication.
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39
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Affiliation(s)
- Kun Dong
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaomin Liu
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Haifeng Dong
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiangping Zhang
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Suojiang Zhang
- State Key Laboratory of Multiphase
Complex Systems, Beijing Key Laboratory of Ionic Liquids Clean Process,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
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40
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Stefanovic R, Ludwig M, Webber GB, Atkin R, Page AJ. Nanostructure, hydrogen bonding and rheology in choline chloride deep eutectic solvents as a function of the hydrogen bond donor. Phys Chem Chem Phys 2017; 19:3297-3306. [DOI: 10.1039/c6cp07932f] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ab initio MD and experiments are combined to reveal how the nanostructures in choline chloride deep eutectic solvents, and hence their properties, are modulated by the hydrogen bond donor structure.
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Affiliation(s)
- Ryan Stefanovic
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | - Michael Ludwig
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | - Grant B. Webber
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | - Alister J. Page
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
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41
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Black JM, Zhu M, Zhang P, Unocic RR, Guo D, Okatan MB, Dai S, Cummings PT, Kalinin SV, Feng G, Balke N. Fundamental aspects of electric double layer force-distance measurements at liquid-solid interfaces using atomic force microscopy. Sci Rep 2016; 6:32389. [PMID: 27587276 PMCID: PMC5009352 DOI: 10.1038/srep32389] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 08/03/2016] [Indexed: 11/09/2022] Open
Abstract
Atomic force microscopy (AFM) force-distance measurements are used to investigate the layered ion structure of Ionic Liquids (ILs) at the mica surface. The effects of various tip properties on the measured force profiles are examined and reveal that the measured ion position is independent of tip properties, while the tip radius affects the forces required to break through the ion layers as well as the adhesion force. Force data is collected for different ILs and directly compared with interfacial ion density profiles predicted by molecular dynamics. Through this comparison it is concluded that AFM force measurements are sensitive to the position of the ion with the larger volume and mass, suggesting that ion selectivity in force-distance measurements are related to excluded volume effects and not to electrostatic or chemical interactions between ions and AFM tip. The comparison also revealed that at distances greater than 1 nm the system maintains overall electroneutrality between the AFM tip and sample, while at smaller distances other forces (e.g., van der waals interactions) dominate and electroneutrality is no longer maintained.
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Affiliation(s)
- Jennifer M Black
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Mengyang Zhu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Pengfei Zhang
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Daqiang Guo
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - M Baris Okatan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Sheng Dai
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Peter T Cummings
- Department of Chemical &Biomolecular Engineering and Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Guang Feng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Nina Balke
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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42
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Elbourne A, McLean B, Voïtchovsky K, Warr GG, Atkin R. Molecular Resolution in situ Imaging of Spontaneous Graphene Exfoliation. J Phys Chem Lett 2016; 7:3118-3122. [PMID: 27463824 DOI: 10.1021/acs.jpclett.6b01323] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
All reported methods of graphene exfoliation require external energy input, most commonly from sonication,1 shaking,2 or stirring.3 The reverse process-aggregation of single or few layer graphene sheets-occurs spontaneously in most solvents. This makes producing, and especially storing, graphene in economic quantities challenging,4,5 which is a significant barrier to widespread commercialization. This study reveals ionic liquids (ILs) can spontaneously exfoliate graphene from graphite at room temperature. The process is thermally activated and follows an Arrhenius-type behavior, resulting in thermodynamically stable IL/graphene suspensions. Using atomic force microscopy, the kinetics of the exfoliation could be followed in situ and with subnanometer resolution, showing that both the size and the charge of the constituent IL ions play a key role. Our results provide a general molecular mechanism underpinning spontaneous graphene exfoliation at room temperature in electrically conducting ILs, paving the way for their adoption in graphene-based technology.
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Affiliation(s)
- Aaron Elbourne
- The University of Newcastle Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy & Resources (Building C), University of Newcastle , Callaghan, New South Wales 2308, Australia
| | - Ben McLean
- The University of Newcastle Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy & Resources (Building C), University of Newcastle , Callaghan, New South Wales 2308, Australia
| | - Kislon Voïtchovsky
- Department of Physics, Durham University , Durham DH1 3LE, United Kingdom
| | - Gregory G Warr
- School of Chemistry, The University of Sydney , Sydney, New South Wales 2006, Australia
| | - Rob Atkin
- The University of Newcastle Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy & Resources (Building C), University of Newcastle , Callaghan, New South Wales 2308, Australia
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43
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Sheehan A, Jurado LA, Ramakrishna SN, Arcifa A, Rossi A, Spencer ND, Espinosa-Marzal RM. Layering of ionic liquids on rough surfaces. NANOSCALE 2016; 8:4094-4106. [PMID: 26821595 DOI: 10.1039/c5nr07805a] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Understanding the behavior of ionic liquids (ILs) either confined between rough surfaces or in rough nanoscale pores is of great relevance to extend studies performed on ideally flat surfaces to real applications. In this work we have performed an extensive investigation of the structural forces between two surfaces with well-defined roughness (<9 nm RMS) in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide by atomic force microscopy. Statistical studies of the measured layer thicknesses, layering force, and layering frequency reveal the ordered structure of the rough IL-solid interface. Our work shows that the equilibrium structure of the interfacial IL strongly depends on the topography of the contact.
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Affiliation(s)
- Alexis Sheehan
- University of Illinois at Urbana-Champaign, Urbana 61801, Illinois, USA.
| | - L Andres Jurado
- University of Illinois at Urbana-Champaign, Urbana 61801, Illinois, USA.
| | | | | | - Antonella Rossi
- ETH Zurich, 8093 Zurich, Switzerland and Università degli Studi di Cagliari, 09042, Italy
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44
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McDonald S, Elbourne A, Warr GG, Atkin R. Metal ion adsorption at the ionic liquid-mica interface. NANOSCALE 2016; 8:906-914. [PMID: 26661934 DOI: 10.1039/c5nr05833c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mica has been employed in many studies of ionic liquid (IL) interfaces on account of its atomic smoothness and well defined surface properties. However, until now it has been unclear whether ions dissolved in ILs can compete with the IL cation and adsorb to mica charge sites. In this work amplitude modulated atomic force microscopy (AM-AFM) has been used to probe metal ion adsorption at the interface of mica with propylammonium nitrate (PAN), a room temperature IL. Lithium, sodium, potassium, magnesium and calcium nitrate salts were added to PAN at a concentration of ∼60 mM. Aluminum nitrate was also investigated, but only at 5 mM because its solubility in PAN is much lower. The AM-AFM images obtained when the metal ions were present are strikingly different to that of pure PAN, indicating that the ions compete effectively with the propylammonium cation and adsorb to negatively charged sites on the mica surface despite their much lower concentration. This is a consequence of electrostatic attractions between the mica charge sites and the metal ions being significantly stronger than for the propylammonium cation; compared to the metal ions the propylammonium charged group is relatively constrained sterically. A distinct honeycomb pattern is noted for the PAN + Al(3+) system, less obviously for the divalent ions and not at all for monovalent ions. This difference is attributed to the strength of electrostatic interactions between metal ions and mica charge sites increasing with the ion charge, which means that divalent and (particularly) trivalent ions are located more precisely above the charged sites of the mica lattice. The images obtained allow important distinctions between metal ion adsorption at mica-water and mica-PAN interfaces to be made.
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Affiliation(s)
- Samila McDonald
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
| | - Aaron Elbourne
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
| | - Gregory G Warr
- School of Chemistry, University of Sydney, Sydney, NSW, Australia
| | - Rob Atkin
- Discipline of Chemistry, The Newcastle Institute for Energy and Resources, The University of Newcastle, Newcastle, NSW, Australia.
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45
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Murphy T, Callear SK, Yepuri N, Shimizu K, Watanabe M, Canongia Lopes JN, Darwish T, Warr GG, Atkin R. Bulk nanostructure of the prototypical ‘good’ and ‘poor’ solvate ionic liquids [Li(G4)][TFSI] and [Li(G4)][NO3]. Phys Chem Chem Phys 2016; 18:17224-36. [DOI: 10.1039/c6cp00176a] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The bulk nanostructures of a prototypical ‘good’ solvate ionic liquid (SIL) and ‘poor’ SIL have been examined using neutron diffraction and empirical potential structure refinement (EPSR) simulated fits.
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Affiliation(s)
- Thomas Murphy
- Priority Research Centre for Advanced Fluids and Interfaces
- Newcastle Institute for Energy & Resources
- University of Newcastle
- Callaghan
- Australia
| | | | - Nageshwar Yepuri
- National Deuteration Facility
- Australian Nuclear Science and Technology Organisation
- Kirrawee DC
- Australia
| | - Karina Shimizu
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049 001 Lisboa
- Portugal
| | - Masayoshi Watanabe
- Department of Chemistry and Biotechnology
- Yokohama National University
- Yokohama 240-8501
- Japan
| | - José N. Canongia Lopes
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049 001 Lisboa
- Portugal
| | - Tamim Darwish
- National Deuteration Facility
- Australian Nuclear Science and Technology Organisation
- Kirrawee DC
- Australia
| | | | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces
- Newcastle Institute for Energy & Resources
- University of Newcastle
- Callaghan
- Australia
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46
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Ivaništšev V, Méndez-Morales T, Lynden-Bell RM, Cabeza O, Gallego LJ, Varela LM, Fedorov MV. Molecular origin of high free energy barriers for alkali metal ion transfer through ionic liquid–graphene electrode interfaces. Phys Chem Chem Phys 2016; 18:1302-10. [DOI: 10.1039/c5cp05973a] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We study mechanisms of solvent-mediated ion interactions with charged surfaces in ionic liquids by molecular dynamics simulations, in an attempt to reveal the main trends that determine ion–electrode interactions in ionic liquids.
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Affiliation(s)
| | - Trinidad Méndez-Morales
- Departamento de Física da Materia Condensada
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | | | - Oscar Cabeza
- Facultade de Ciencias
- Universidade da Coruña
- A Coruña
- Spain
| | - Luis J. Gallego
- Departamento de Física da Materia Condensada
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | - Luis M. Varela
- Departamento de Física da Materia Condensada
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | - Maxim V. Fedorov
- Department of Physics
- Scottish Universities Physics Alliance (SUPA)
- Strathclyde University
- John Anderson Building
- Glasgow
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47
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Murphy T, Callear SK, Warr GG, Atkin R. Dissolved chloride markedly changes the nanostructure of the protic ionic liquids propylammonium and ethanolammonium nitrate. Phys Chem Chem Phys 2016; 18:17169-82. [DOI: 10.1039/c5cp06947e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bulk nanostructure of 15 mol% propylammonium chloride (PACl) dissolved in propylammonium nitrate (PAN) and 15 mol% ethanolammonium chloride (EtACl) in ethanolammonium nitrate (EtAN) has been determined using neutron diffraction with empirical potential structure refinement fits.
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Affiliation(s)
- Thomas Murphy
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
| | | | | | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces
- The University of Newcastle
- Callaghan
- Australia
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48
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Abstract
Recent advances in experimental and computational techniques have allowed for an accurate description of the adsorption of ionic liquids on metallic electrodes. It is now well-established that they adopt a multilayered structure and that the composition of the layers changes with the potential of the electrode. In some cases, potential-driven ordering transitions in the first adsorbed layer have been observed in experiments probing the interface on the molecular scale or by molecular simulations. This perspective gives an overview of the current understanding of such transitions and of their potential impact on the physical and (electro)chemical processes at the interface. In particular, peaks in the differential capacitance, slow dynamics at the interface, and changes in the reactivity have been reported in electrochemical studies. Interfaces between ionic liquids and metallic electrodes are also highly relevant for their friction properties, the voltage-dependence of which opens the way to exciting applications.
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Affiliation(s)
- Benjamin Rotenberg
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005, Paris, France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 80039 Amiens Cedex, France
| | - Mathieu Salanne
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005, Paris, France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 80039 Amiens Cedex, France
- Maison de la Simulation, USR 3441, CEA - CNRS - INRIA - Université Paris-Sud -Université de Versailles, F-91191 Gif-sur-Yvette, France
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49
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Dolan A, Atkin R, Warr GG. The origin of surfactant amphiphilicity and self-assembly in protic ionic liquids. Chem Sci 2015; 6:6189-6198. [PMID: 30090234 PMCID: PMC6054141 DOI: 10.1039/c5sc01202c] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/04/2015] [Indexed: 11/21/2022] Open
Abstract
The nature of amphiphilic self-assembly in alkylammonium protic ionic liquids (PILs) is examined by systematically varying the ionic structure and composition, H-bonding capacity, and nanostructure of both the PIL and micelle-forming cationic surfactant, and contrasted with self-assembly in water. Using small-angle neutron scattering, micelle structure and concentrations are determined for primary - quaternary dodecylammonium salts in nitrate and thiocyanate PILs. While the solvophobic driving force depends only on the average polarity of the PIL, surprisingly strong, specific interactions of the head group and counterion with the PIL H-bond network are found. This suggests the importance of developing designer amphiphiles for assembling soft matter structures in PILs.
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Affiliation(s)
- Andrew Dolan
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia .
| | - Rob Atkin
- Centre for Advanced Particle Processing and Transport , Chemistry Building , The University of Newcastle , Callaghan , NSW 2308 , Australia
| | - Gregory G Warr
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia .
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50
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García G, Atilhan M, Aparicio S. Theoretical Study of Renewable Ionic Liquids in the Pure State and with Graphene and Carbon Nanotubes. J Phys Chem B 2015; 119:12224-37. [DOI: 10.1021/acs.jpcb.5b03809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gregorio García
- Department
of Chemistry, University of Burgos, 09001 Burgos, Spain
| | - Mert Atilhan
- Department
of Chemical Engineering, Qatar University, P.O. Box 2713, Doha, Qatar
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