551
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Bonacchi S, El Garah M, Ciesielski A, Herder M, Conti S, Cecchini M, Hecht S, Samorì P. Surface-induced selection during in situ photoswitching at the solid/liquid interface. Angew Chem Int Ed Engl 2015; 54:4865-9. [PMID: 25728405 DOI: 10.1002/anie.201412215] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Indexed: 01/24/2023]
Abstract
Here we report for the first time a submolecularly resolved scanning tunneling microscopy (STM) study at the solid/liquid interface of the in situ reversible interconversion between two isomers of a diarylethene photoswitch, that is, open and closed form, self-assembled on a graphite surface. Prolonged irradiation with UV light led to the in situ irreversible formation of another isomer as by-product of the reaction, which due to its preferential physisorption accumulates at the surface. By making use of a simple yet powerful thermodynamic model we provide a quantitative description for the observed surface-induced selection of one isomeric form.
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Affiliation(s)
- Sara Bonacchi
- Nanochemistry Laboratory, ISIS & icFRC, Université de Strasbourg & CNRS, 8 allée Gaspard Monge, 67000 Strasbourg (France)
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552
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Wang X, Xiong Z, Liu Z, Zhang T. Exfoliation at the liquid/air interface to assemble reduced graphene oxide ultrathin films for a flexible noncontact sensing device. Adv Mater 2015; 27:1370-5. [PMID: 25522328 DOI: 10.1002/adma.201404069] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/15/2014] [Indexed: 05/27/2023]
Abstract
Reduced graphene oxide ultrathin films are fabricated by a reproducible exfoliation method at the liquid/air interface, and they show high transparency, tunable sheet resistance, uniform electric conductivity, and structural homogeneity over a large area. A flexible relative humidity sensing matrix is demonstrated and it is shown to be excellent for close proximity sensing without touching it. This method opens up a novel avenue for future human-machine interaction applications.
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Affiliation(s)
- Xuewen Wang
- i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, PR China; School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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553
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Zhang X, Shen Y, Zhang Q, Gu L, Hu Y, Du J, Lin Y, Nan CW. Ultrahigh energy density of polymer nanocomposites containing BaTiO3@TiO2 nanofibers by atomic-scale interface engineering. Adv Mater 2015; 27:819-824. [PMID: 25492492 DOI: 10.1002/adma.201404101] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/05/2014] [Indexed: 06/04/2023]
Abstract
Atomic-scale interface engineering in BaTiO3@TO2 nanofibers (TiO2 nano-fibers embedded with BaTiO3 nano-particles) leads to concurrent enhancement of electric displacement and breakdown strength in poly(vinylidene fluoride) (PVDF)-based nanocomposites. An ultrahigh energy density of ≈20 J cm(-3) is achieved with only 3 vol% nanofibers, which is by far the highest discharged energy density of PVDF-based nanocomposites.
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Affiliation(s)
- Xin Zhang
- School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
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554
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Parafita Couto MC, Mueller Gathercole VC, Stadthagen-González H. Interface strategies in monolingual and end-state L2 Spanish grammars are not that different. Front Psychol 2015; 5:1525. [PMID: 25628580 PMCID: PMC4292789 DOI: 10.3389/fpsyg.2014.01525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/10/2014] [Indexed: 11/28/2022] Open
Abstract
This study explores syntactic, pragmatic, and lexical influences on adherence to SV and VS orders in native and fluent L2 speakers of Spanish. A judgment task examined 20 native monolingual and 20 longstanding L2 bilingual Spanish speakers' acceptance of SV and VS structures. Seventy-six distinct verbs were tested under a combination of syntactic and pragmatic constraints. Our findings challenge the hypothesis that internal interfaces are acquired more easily than external interfaces (Sorace, 2005, 2011; Sorace and Filiaci, 2006; White, 2006). Additional findings are that (a) bilinguals' judgments are less firm overall than monolinguals' (i.e., monolinguals are more likely to give extreme “yes” or “no” judgments) and (b) individual verbs do not necessarily behave as predicted under standard definitions of unaccusatives and unergatives. Correlations of the patterns found in the data with verb frequencies suggest that usage-based accounts of grammatical knowledge could help provide insight into speakers' knowledge of these constructs.
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Affiliation(s)
- María C Parafita Couto
- Leiden University Center for Linguistics and Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands
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555
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Suhina T, Weber B, Carpentier CE, Lorincz K, Schall P, Bonn D, Brouwer AM. Fluorescence microscopy visualization of contacts between objects. Angew Chem Int Ed Engl 2015; 54:3688-91. [PMID: 25631338 PMCID: PMC4471612 DOI: 10.1002/anie.201410240] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 11/26/2014] [Indexed: 11/20/2022]
Abstract
The area of contact between two objects was detected by using the strong enhancement of the fluorescence of rigidochromic probe molecules attached to one of the surfaces. Confinement of the molecules suppresses nonradiative decay and turns on the fluorescence. The approach is demonstrated by imaging of the contact area of a plastic sphere in contact with a flat glass surface. Our results agree excellently with the prediction of Hertz’s classical theory based on elastic deformation.
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Affiliation(s)
- Tomislav Suhina
- van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam (The Netherlands); Institute of Physics, University of Amsterdam, P.O. Box 94485, 1090 GL Amsterdam (The Netherlands)
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556
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Abstract
Engineered wettability is a traditional, yet key issue in surface science and attracts tremendous interest in solving large-scale practical problems. Recently, different super-wettability systems have been discovered in both nature and experiments. In this Review we present three types of super-wettability, including the three-dimensional, two-dimensional, and one-dimensional material surfaces. By combining different super-wettabilities, novel interfacial functional systems could be generated and integrated into devices for use in tackling current and the future problems including resources, energy, environment, and health.
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Affiliation(s)
- Liping Wen
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (P.R. China)
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557
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Butler BM, Gerek ZN, Kumar S, Ozkan SB. Conformational dynamics of nonsynonymous variants at protein interfaces reveals disease association. Proteins 2015; 83:428-35. [PMID: 25546381 DOI: 10.1002/prot.24748] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/20/2014] [Accepted: 12/10/2014] [Indexed: 12/12/2022]
Abstract
Recent studies have shown that the protein interface sites between individual monomeric units in biological assemblies are enriched in disease-associated non-synonymous single nucleotide variants (nsSNVs). To elucidate the mechanistic underpinning of this observation, we investigated the conformational dynamic properties of protein interface sites through a site-specific structural dynamic flexibility metric (dfi) for 333 multimeric protein assemblies. dfi measures the dynamic resilience of a single residue to perturbations that occurred in the rest of the protein structure and identifies sites contributing the most to functionally critical dynamics. Analysis of dfi profiles of over a thousand positions harboring variation revealed that amino acid residues at interfaces have lower average dfi (31%) than those present at non-interfaces (50%), which means that protein interfaces have less dynamic flexibility. Interestingly, interface sites with disease-associated nsSNVs have significantly lower average dfi (23%) as compared to those of neutral nsSNVs (42%), which directly relates structural dynamics to functional importance. We found that less conserved interface positions show much lower dfi for disease nsSNVs as compared to neutral nsSNVs. In this case, dfi is better as compared to the accessible surface area metric, which is based on the static protein structure. Overall, our proteome-wide conformational dynamic analysis indicates that certain interface sites play a critical role in functionally related dynamics (i.e., those with low dfi values), therefore mutations at those sites are more likely to be associated with disease.
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558
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Graužinytė M, Forth J, Rumble KA, Clegg PS. Particle-stabilized water droplets that sprout millimeter-scale tubes. Angew Chem Int Ed Engl 2014; 54:1456-60. [PMID: 25488306 DOI: 10.1002/anie.201408365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/10/2014] [Indexed: 11/12/2022]
Abstract
Millimeter-scale tubes are observed to sprout from water droplets injected into a bath of toluene containing ethanol and silica colloids. This phenomenon requires that first a membrane is formed by the colloids which self-assemble at the droplet interface, and second, that the ethanol preferentially partitions into the aqueous phase leading to an internal over-pressure. Tube growth, eruption, and shuffling droplets are subsequently observed, depending on the concentration of ethanol and colloids selected. This work opens many possibilities in the field of biomimetic droplets for fundamental studies of artificial growth at the microscale and for emulsion-related applications.
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Affiliation(s)
- Miglė Graužinytė
- School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3 JZ (UK)
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559
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Li J, Li Y, Chan CY, Kwok RT, Li H, Zrazhevskiy P, Gao X, Sun JZ, Qin A, Tang BZ. An aggregation-induced-emission platform for direct visualization of interfacial dynamic self-assembly. Angew Chem Int Ed Engl 2014; 53:13518-13522. [PMID: 25363745 PMCID: PMC4370284 DOI: 10.1002/anie.201408757] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/15/2014] [Indexed: 11/08/2022]
Abstract
An in-depth understanding of dynamic interfacial self-assembly processes is essential for a wide range of topics in theoretical physics, materials design, and biomedical research. However, direct monitoring of such processes is hampered by the poor imaging contrast of a thin interfacial layer. We report in situ imaging technology capable of selectively highlighting self-assembly at the phase boundary in real time by employing the unique photophysical properties of aggregation-induced emission. Its application to the study of breath-figure formation, an immensely useful yet poorly understood phenomenon, provided a mechanistic model supported by direct visualization of all main steps and fully corroborated by simulation and theoretical analysis. This platform is expected to advance the understanding of the dynamic phase-transition phenomena, offer insights into interfacial biological processes, and guide development of novel self-assembly technologies.
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Affiliation(s)
- Junwei Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 (China)
- Department of Bioengineering, University of Washington Seattle, WA (USA)
| | - Yuan Li
- Physics Department, Wake Forest University Winston-Salem, NC 27106 (USA)
| | - Carrie Y.K. Chan
- Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials, and State Key Laboratory of Molecular Neuroscience The Hong Kong University of Science & Technology Clear Water Bay, Kowloon, Hong Kong (China)
| | - Ryan T.K. Kwok
- Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials, and State Key Laboratory of Molecular Neuroscience The Hong Kong University of Science & Technology Clear Water Bay, Kowloon, Hong Kong (China)
| | - Hongkun Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 (China)
| | - Pavel Zrazhevskiy
- Department of Bioengineering, University of Washington Seattle, WA (USA)
| | - Xiaohu Gao
- Department of Bioengineering, University of Washington Seattle, WA (USA)
| | - Jing Zhi Sun
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 (China)
| | - Anjun Qin
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 (China)
- State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 (China)
| | - Ben Zhong Tang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering Zhejiang University, Hangzhou 310027 (China)
- Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials, and State Key Laboratory of Molecular Neuroscience The Hong Kong University of Science & Technology Clear Water Bay, Kowloon, Hong Kong (China)
- State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 (China)
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560
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Jordens S, Riley EE, Usov I, Isa L, Olmsted PD, Mezzenga R. Adsorption at liquid interfaces induces amyloid fibril bending and ring formation. ACS Nano 2014; 8:11071-9. [PMID: 25338060 DOI: 10.1021/nn504249x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Protein fibril accumulation at interfaces is an important step in many physiological processes and neurodegenerative diseases as well as in designing materials. Here we show, using β-lactoglobulin fibrils as a model, that semiflexible fibrils exposed to a surface do not possess the Gaussian distribution of curvatures characteristic for wormlike chains, but instead exhibit a spontaneous curvature, which can even lead to ring-like conformations. The long-lived presence of such rings is confirmed by atomic force microscopy, cryogenic scanning electron microscopy, and passive probe particle tracking at air- and oil-water interfaces. We reason that this spontaneous curvature is governed by structural characteristics on the molecular level and is to be expected when a chiral and polar fibril is placed in an inhomogeneous environment such as an interface. By testing β-lactoglobulin fibrils with varying average thicknesses, we conclude that fibril thickness plays a determining role in the propensity to form rings.
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Affiliation(s)
- Sophia Jordens
- Department of Health Sciences & Technology, Laboratory of Food & Soft Materials, ETH Zurich , 8092 Zurich, Switzerland
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561
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Bhatt R, Bhattacharya S, Basu R, Ahmad S, Chauhan AK, Okram GS, Bhatt P, Roy M, Navaneethan M, Hayakawa Y, Debnath AK, Singh A, Aswal DK, Gupta SK. Enhanced thermoelectric properties of selenium-deficient layered TiSe(2-x): a charge-density-wave material. ACS Appl Mater Interfaces 2014; 6:18619-18625. [PMID: 25318103 DOI: 10.1021/am503477z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the present work, we report on the investigation of low-temperature (300-5 K) thermoelectric properties of hot-pressed TiSe2, a charge-density-wave (CDW) material. We demonstrate that, with increasing hot-pressing temperature, the density of TiSe2 increases and becomes nonstoichiometric owing to the loss of selenium. X-ray diffraction, scanning electron microscopy, and transimission electron microscopy results show that the material consists of a layered microstructure with several defects. Increasing the hot-press temperature in nonstoichiometric TiSe2 leads to a reduction of the resistivity and enhancement of the Seebeck coefficient in concomitent with suppression of CDW. Samples hot-pressed at 850 °C exhibited a minimum thermal conductivity (κ) of 1.5 W/m·K at 300 K that, in turn, resulted in a figure-of-merit (ZT) value of 0.14. This value is higher by 6 orders of magnitude compared to 1.49 × 10(-7) obtained for cold-pressed samples annealed at 850 °C. The enhancement of ZT in hot-pressed samples is attributed to (i) a reduced thermal conductivity owing to enhanced phonon scattering and (ii) improved power factor (α(2)σ).
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Affiliation(s)
- Ranu Bhatt
- Technical Physics Division, ‡Astrophysical Sciences Division, ∥Solid State Physics Division, and ⊥Chemistry Division, Bhabha Atomic Research Centre , Mumbai 400 085, India
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562
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Abstract
We present a facile approach for producing large and monodisperse core-shell drops with ultrathin shells using a single-step process. A biphasic compound jet is introduced into a quiescent third (outer) phase that ruptures to form core-shell drops. Ultrathin shelled drops could only be produced within a certain range of surfactant concentrations and flow rates, highlighting the effect of interfacial tension in engulfing the core in a thin shell. An increase in surfactant concentrations initially resulted in drops with thinner shells. However, the drops with thinnest shells were obtained at an optimum surfactant concentration, and a further increase in the surfactant concentrations increased the shell thickness. Highly monodisperse (coefficient of variation smaller than 3 %) core-shell drops with diameter of ∼200 μm-2 mm with shell thickness as small as ∼2 μm were produced. The resulting drops were stable enough to undergo polymerisation and produce ultrathin shelled capsules.
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Affiliation(s)
- Ankur S Chaurasia
- Department of Physics, King's College London, Strand, London, WC2R 2 LS (UK)
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563
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Ding Y, Sun X, Zhang L, Mao S, Xie Z, Liu ZW, Su DS. Entrapping an ionic liquid with nanocarbon: the formation of a tailorable and functional surface. Angew Chem Int Ed Engl 2014; 54:231-5. [PMID: 25370337 DOI: 10.1002/anie.201408201] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/08/2014] [Indexed: 11/10/2022]
Abstract
An interface microenvironment between nanocarbon and ionic liquids (ILs) is presented. By an entrapping effect, a few layers of ILs can be finely deposited on the surface of nanocarbon, endowing amazingly tailorable surface properties. The entrapped IL layer, which was believed to be unable to be charred under pyrolysis conditions alone, can be further carbonized to a functional carbon layer. C, B, and N were confirmed to share the same hexagonal ring in the resultant layer, which provides more designable electronic properties.
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Affiliation(s)
- Yuxiao Ding
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)
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564
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Abstract
Engineering the wettability of solid materials is a traditional, yet key issue in surface science and attracts tremendous interest by researchers in diverse fields. Recently, different superwetting phenomena have been discovered in both nature and experimental results. Therefore, in this review, various superwetting states, leading to a "superwettability" system, are summarized and predicted. Fundamental rules for understanding superwettability are discussed, mainly taking superhydrophobicity in air as an example. Then, some recent application progress of individual members of this "superwettability" system are introduced. Notably, several novel application fields, mainly gas, water, oil and/or other liquid environments, are presented in the following section. By combining different members of this "superwettability" system, new interfacial functions can be generated, allowing unexpected applications, such as in environmental protection, energy, green industry, and many other important domains. Finally, the future development of this interesting "superwettability" system is discussed.
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Affiliation(s)
- Ye Tian
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing, 100190, P. R. China
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565
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Wang F, Liu J. Liposome supported metal oxide nanoparticles: interaction mechanism, light controlled content release, and intracellular delivery. Small 2014; 10:3927-31. [PMID: 24861966 DOI: 10.1002/smll.201400850] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/04/2014] [Indexed: 05/21/2023]
Abstract
Zwitterionic phosphotydylcholine lipo-somes stably adsorb a number of metal oxide nanoparticles via its phosphate group. This is different from physisorption and fusion with SiO2. The hybrid materials can be internalized by cancer cells and TiO2 allows light controlled liposome content release.
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Affiliation(s)
- Feng Wang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
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566
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Padmanabhan KA, Gleiter H. On the structure of grain/interphase boundaries and interfaces. Beilstein J Nanotechnol 2014; 5:1603-1615. [PMID: 25383273 PMCID: PMC4222453 DOI: 10.3762/bjnano.5.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 08/27/2014] [Indexed: 06/04/2023]
Abstract
Grain/interphase boundaries/interfaces of varying misorientations, free volume fractions, curvatures and irregularities are present in materials, both 3D and 2D, regardless of whether these materials are crystalline or amorphous/glassy. Therefore, a question arises about the central idea on which a general description of grain/interphase boundaries/interfaces can and should be based. It is suggested that a generalized model of a structural/basic unit (crystalline, non-crystalline or of any scale), which depends on the interatomic (including electronic) interactions, the spatial distribution of the atoms and electrons, the number of atoms and free volume fraction present in the structural/basic unit and the experimental conditions should serve the purpose. As the development of a quantitative model, which reflects the effects of all these variables is difficult, slightly defective material boundaries are often modeled by treating the entire boundary as planar and by using the concepts of crystallography. For highly disordered boundaries, a description in terms of a representative volume, made up of a non-crystalline basic unit or a combination of such units, which depend on interatomic (including electronic) interactions and forces, is advocated. The size, shape, free volume fraction and number of atoms in the representative volume could differ with material composition and experimental conditions. In the latter approach, it is assumed that all processes connected to a problem on hand is contained within this representative volume. The unresolved issues are identified.
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Affiliation(s)
- K Anantha Padmanabhan
- School of Engineering Sciences & Technology and Centre for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500 046, India
| | - Herbert Gleiter
- Karlsruhe Institute of Technology (North Campus), Institute of Nanotechnology, Helmholtz Platz, 76344 Eggenstein, Germany
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567
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Cedeno D, Krawicz A, Doak P, Yu M, Neaton JB, Moore GF. Using Molecular Design to Control the Performance of Hydrogen-Producing Polymer-Brush-Modified Photocathodes. J Phys Chem Lett 2014; 5:3222-3226. [PMID: 26276336 DOI: 10.1021/jz5016394] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Attachment of difluoroborylcobaloxime catalysts to a polymer-brush-modified GaP semiconductor allows improved hydrogen production levels and photoelectrochemical performance under aqueous acidic conditions (pH = 4.5) as compared to the performance of electrodes without catalyst treatment. The catalytic assembly used in this work incorporates a boron difluoride (BF2) capping group on the glyoximate ligand of the catalyst, a synthetic modification previously used to enhance the stability of nonsurface-attached complexes toward acid hydrolysis and to shift the cobalt reduction potentials of the complex to less negative, and thus technologically more relevant, values. The pH-dependent photoresponses of the cobaloxime- and difluoroborylcobaloxime- modified semiconductors are shown to be consistent with those from analogous studies using non-surface-attached cobaloxime catalysts as well as catalysts supported on conductive electrodes. Thus, this work illustrates the potential to control and optimize the properties of visible-light-absorbing semiconductors using polymeric overcoating techniques coupled with the principles of synthetic molecular design.
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Affiliation(s)
| | | | | | | | - Jeffrey B Neaton
- □Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
| | - Gary F Moore
- ∇Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
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568
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Wang Z, Liu Y, Tao P, Shen Q, Yi N, Zhang F, Liu Q, Song C, Zhang D, Shang W, Deng T. Bio-inspired evaporation through plasmonic film of nanoparticles at the air-water interface. Small 2014; 10:3234-9. [PMID: 24821378 DOI: 10.1002/smll.201401071] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Indexed: 05/03/2023]
Abstract
Plasmonic gold nanoparticles self-assembled at the air-water interface to produce an evaporative surface with local control inspired by skins and plant leaves. Fast and efficient evaporation is realized due to the instant and localized plasmonic heating at the evaporative surface. The bio-inspired evaporation process provides an alternative promising approach for evaporation, and has potential applications in sterilization, distillation, and heat transfer.
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Affiliation(s)
- Zhenhui Wang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
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569
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Yu Y, Yan C, Zheng Z. Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors. Adv Mater 2014; 26:5508-16. [PMID: 24458846 DOI: 10.1002/adma.201305558] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 12/03/2013] [Indexed: 05/24/2023]
Abstract
Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided.
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Affiliation(s)
- You Yu
- Nanotechnology Center, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, China; The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, 518000, China
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570
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Li Z, Weeraman CN, Gibbs-Davis JM. Following the azide-alkyne cycloaddition at the silica/solvent interface with sum frequency generation. Chemphyschem 2014; 15:2247-51. [PMID: 24800780 DOI: 10.1002/cphc.201402161] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Indexed: 11/10/2022]
Abstract
The Cu(I) -catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) has arisen as one of the most useful chemical transformations for introducing complexity onto surfaces and materials owing to its functional-group tolerance and high yield. However, methods for monitoring such reactions in situ at the widely used silica/solvent interface are hampered by challenges associated with probing such buried interfaces. Using the surface-specific technique broadband sum frequency generation (SFG), we monitored the reaction of a benzyl azide monolayer in real time at the silica/methanol interface. A strong peak at 2096 cm(-1) assigned to the azides was observed for the first time by SFG. Using a cyano-substituted alkyne, the decrease of the azide peak and the increase of the cyano peak (2234 cm(-1) ) were probed simultaneously. From the kinetic analysis, the reaction order with respect to copper was determined to be 2.1, suggesting that CuAAC on the surface follows a similar mechanism as in solution.
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Affiliation(s)
- Zhiguo Li
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2 (Canada)
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571
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Bai Y, Abbasi R, Wang C, Abbott NL. Liquid crystals anchored on mixed monolayers of chiral versus achiral molecules: continuous change in orientation as a function of enantiomeric excess. Angew Chem Int Ed Engl 2014; 53:8079-83. [PMID: 24841757 PMCID: PMC4241358 DOI: 10.1002/anie.201402770] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Indexed: 11/10/2022]
Abstract
The orientations of liquid crystals (LCs) anchored on monolayers formed from mixtures of chiral versus achiral molecules were compared. Changes in the enantiomeric excess of mixed monolayers of chiral dipeptides gave rise to continuous changes in the orientations of nematic LCs, allowing arbitrary tuning of the azimuthal orientations of LCs over a range of ≈100°. In contrast, the same LCs exhibited discontinuous changes in orientation on surfaces presenting mixtures of achiral molecules. These striking differences in the anchoring of LCs on surfaces presenting chiral versus achiral molecules provide insights into the molecular origins of ordering transitions of LCs, and provide new principles based on chiral monolayers for the rational design of surfaces that permit continuous tuning of the orientations of LCs.
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Affiliation(s)
- Yiqun Bai
- Department of Chemical and Biological Engineering University of Wisconsin-Madison 1415 Engineering Drive, Madison WI 53705, USA
| | - Reza Abbasi
- Department of Chemical and Biological Engineering University of Wisconsin-Madison 1415 Engineering Drive, Madison WI 53705, USA
| | - Chenxuan Wang
- Department of Chemical and Biological Engineering University of Wisconsin-Madison 1415 Engineering Drive, Madison WI 53705, USA
| | - Nicholas L. Abbott
- Department of Chemical and Biological Engineering University of Wisconsin-Madison 1415 Engineering Drive, Madison WI 53705, USA
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572
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Abstract
Guilty as charged: Water is often modeled as a dielectric continuum, but the molecular structure of water is asymmetric. Two ions that have a virtually identical size, shape, and structure, but an opposite charge sign have been investigated to see whether charge makes a fundamental difference to water structuring. The spectroscopic data for the hydration and interface structures are found to be remarkably different for opposite charges.
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Affiliation(s)
- Rüdiger Scheu
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Féderale de Lausanne (EPFL), 1015 Lausanne (Switzerland)
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573
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Abstract
Ultrafast dynamics of molecules at solid-liquid interfaces are of outstanding importance in chemistry and physics due to their involvement in processes of heterogeneous catalysis. We present a new spectroscopic approach to resolve coherent, time-resolved, 2D vibrational spectra as well as ultrafast vibrational relaxation dynamics of molecules adsorbed on metallic thin films in contact with liquids. The setup is based on the technique of attenuated total reflectance (ATR) spectroscopy, which is used at interfaces between materials that exhibit different refractive indices. As a sample molecule, we consider carbon monoxide adsorbed in different binding configurations on different metals and resolve its femtosecond vibrational dynamics. It is presented that mid-infrared, multidimensional ATR spectroscopy allows for obtaining a surface-sensitive characterization of adsorbates' vibrational relaxation, spectral diffusion dynamics, and sample inhomogeneity on the femtosecond time scale.
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Affiliation(s)
- Jan Philip Kraack
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Davide Lotti
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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574
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Seidel J, Trassin M, Zhang Y, Maksymovych P, Uhlig T, Milde P, Köhler D, Baddorf AP, Kalinin SV, Eng LM, Pan X, Ramesh R. Electronic properties of isosymmetric phase boundaries in highly strained Ca-Doped BiFeO₃. Adv Mater 2014; 26:4376-4380. [PMID: 24729350 DOI: 10.1002/adma.201400557] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/19/2014] [Indexed: 06/03/2023]
Affiliation(s)
- Jan Seidel
- School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA; Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
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575
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Qian Z, Peng T, Wang J, Qu L. Construction of Hybrid Supercapacitor-Batteries with dual-scale shelled architecture. ChemSusChem 2014; 7:1881-1887. [PMID: 24782290 DOI: 10.1002/cssc.201400148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/04/2014] [Indexed: 06/03/2023]
Abstract
Pseudocapacitors bridge the gap between supercapacitors and batteries. Controllable microstructures grown on substrates have achieved success with regard to energy storage. However, traditional designs have only focused on the surface of scaffolds, which results in high specific capacitance values for the electroactive material rather than the electrodes. Inspired by slurry-casting, a dual-scale shell-structured NiCo2 O4 on nickel foam was assembled by using a simple and flexible solution-based strategy. First, NiCo2 O4 nanosheets covering the Ni foam skeleton surface loosely (the sample is denoted as 'pasted') is obtained by a solution-grown and 'dip-and-dry' process (in a cobalt-nickel hydroxide solution) followed by annealing. Secondly, the NiCo2 O4 nanosheets are filled in the pores of the Ni scaffold (the obtained material is denoted as 'tailored') through chemical bath deposition process followed by annealing. The capacitance per weight of electroactive materials is not outstanding (1029 F g(-1) at 10 mA cm(-2) ), but is competitive with regard to area (3.23 F cm(-2) at 10 mA cm(-2) ). However, features in the cycling performance imply that the electrode exhibits a hybrid supercapacitor-battery behavior and that thermodynamic hysteresis promotes the 'breaking' and 'fusing' behavior of the material. The overall design highlights a new pathway to step out from surface to space.
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Affiliation(s)
- Zhongyu Qian
- Key Laboratory of Superlight Material and Surface Technology, Harbin Engineering University, Harbin, 150001 (PR China)
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576
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Park JT, Ahn SH, Roh DK, Lee CS, Kim JH. Multifunctional organized mesoporous tin oxide films templated by graft copolymers for dye-sensitized solar cells. ChemSusChem 2014; 7:2037-2047. [PMID: 24678065 DOI: 10.1002/cssc.201301215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/25/2014] [Indexed: 06/03/2023]
Abstract
The synthesis of organized mesoporous SnO2 films with high porosity, larger pores, and good interconnectivity, obtained by sol-gel templating with an amphiphilic graft copolymer, poly(vinyl chloride)-graft-poly(oxyethylene methacrylate), is reported. An improved performance of dye-sensitized solar cells (DSSCs) is demonstrated by the introduction of a 400 nm thick organized mesoporous SnO2 interfacial (om-SnO2 IF) layer between nanocrystalline TiO2 (nc-TiO2 ) and a fluorine-doped tin oxide substrate. To elucidate the improved efficiency, the structural, optical, and electrochemical properties of the devices were characterized by SEM, UV/Vis spectroscopy, noncontact 3D surface profilometry, intensity-modulated photocurrent/voltage spectroscopy, incident photon-to-electron conversion efficiency, and electrochemical impedance spectroscopy measurements. The energy-conversion efficiency of the solid polymerized ionic liquid based DSSC fabricated with the om-SnO2 IF/nc-TiO2 photoanode reached 5.9% at 100 mW cm(-2) ; this is higher than those of neat nc-TiO2 (3.5%) and organized mesoporous TiO2 interfacial/nc-TiO2 layer (5.4%) photoanodes. The improved efficiency is attributed to the antireflective property, cascadal energy band gap, good interconnectivity, and high electrical conductivity of the om-SnO2 IF layer, which results in enhanced light harvesting, increased electron transport, reduced charge recombination, and decreased interfacial/internal resistance.
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Affiliation(s)
- Jung Tae Park
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (South Korea), Fax: (+82) 2-312-6401
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577
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Kovalenko A, Polavarapu P, Gallani JL, Pourroy G, Waton G, Krafft MP. Super-elastic air/water interfacial films self-assembled from soluble surfactants. Chemphyschem 2014; 15:2440-4. [PMID: 24953549 DOI: 10.1002/cphc.201402248] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Indexed: 11/11/2022]
Abstract
We show that water-soluble monosodic salts of F-alkyl phosphates C(n)F(2n+1) (CH2)2OP(O)(OH)2, with n=8 and 10 (F8H2Phos and F10H2Phos) form Gibbs films with exceptionally high dilational viscoelastic modules E that reach ~900 mN m(-1) in the condensed phases. These E values are up to one order of magnitude larger than those recorded for phospholipid, protein and polymer films commonly considered as highly viscoelastic. F8H2Phos.1Na undergoes a transition between a liquid-expanded and a liquid-condensed phase. In the case of F10H2Phos.1Na, a transition occurs between a gas phase of surface domains, in which the molecules are densely packed, and a liquid-condensed phase.
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Affiliation(s)
- Artem Kovalenko
- Institut Charles Sadron (UPR CNRS 22), University of Strasbourg, 23 rue du Loess, 67034 Strasbourg Cedex (France)
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578
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Qu W, Dorjpalam E, Rajagopalan R, Randall CA. Role of additives in formation of solid-electrolyte interfaces on carbon electrodes and their effect on high-voltage stability. ChemSusChem 2014; 7:1162-1169. [PMID: 24677808 DOI: 10.1002/cssc.201300858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/11/2013] [Indexed: 06/03/2023]
Abstract
The in situ modification of a lithium hexafluorophosphate-based electrolyte using a molybdenum oxide catalyst and small amount of water (1 vol %) yields hydrolysis products such as mono-, di-, and alkylfluorophosphates. The electrochemical stability of ultrahigh-purity, high-surface-area carbon electrodes derived from polyfurfuryl alcohol was tested using the modified electrolyte. Favorable modification of the solid electrolyte interface (SEI) layer on the activated carbon electrode increased the cyclable electrochemical voltage window (4.8-1.2 V vs. Li/Li(+)). The chemical modification of the SEI layer induced by electrolyte additives was characterized by using X-ray photoelectron spectroscopy.
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Affiliation(s)
- Weiguo Qu
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (USA), Fax: (+1) 814-863-8561 www.personal.psu.edu/faculty/r/u/rur12
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579
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Lim KG, Choi MR, Kim JH, Kim DH, Jung GH, Park Y, Lee JL, Lee TW. Role of ultrathin metal fluoride layer in organic photovoltaic cells: mechanism of efficiency and lifetime enhancement. ChemSusChem 2014; 7:1125-1132. [PMID: 24616332 DOI: 10.1002/cssc.201301152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Indexed: 06/03/2023]
Abstract
Although rapid progress has been made recently in bulk heterojunction organic solar cells, systematic studies on an ultrathin interfacial layer at the electron extraction contact have not been conducted in detail, which is important to improve both the device efficiency and the lifetime. We find that an ultrathin BaF2 layer at the electron extraction contact strongly influences the open-circuit voltage (Voc ) as the nanomorphology evolves with increasing BaF2 thickness. A vacuum-deposited ultrathin BaF2 layer grows by island growth, so BaF2 layers with a nominal thickness less than that of single-coverage layer (≈3 nm) partially cover the polymeric photoactive layer. As the nominal thickness of the BaF2 layer increased to that of a single-coverage layer, the Voc and power conversion efficiency (PCE) of the organic photovoltaic cells (OPVs) increased but the short-circuit current remained almost constant. The fill factor and the PCE decreased abruptly as the thickness of the BaF2 layer exceeded that of a single-coverage layer, which was ascribed to the insulating nature of BaF2 . We find the major cause of the increased Voc observed in these devices is the lowered work function of the cathode caused by the reaction and release of Ba from thin BaF2 films upon deposition of Al. The OPV device with the BaF2 layer showed a slightly improved maximum PCE (4.0 %) and a greatly (approximately nine times) increased device half-life under continuous simulated solar irradiation at 100 mW cm(-2) as compared with the OPV without an interfacial layer (PCE=2.1 %). We found that the photodegradation of the photoactive layer was not a major cause of the OPV degradation. The hugely improved lifetime with cathode interface modification suggests a significant role of the cathode interfacial layer that can help to prolong device lifetimes.
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Affiliation(s)
- Kyung-Geun Lim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Nam-gu, Pohang, Gyungbuk 790-784 (Korea)
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580
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Wang L, Wang D, Dong Z, Zhang F, Jin J. Interface chemistry engineering of protein-directed SnO₂ nanocrystal-based anode for lithium-ion batteries with improved performance. Small 2014; 10:998-1007. [PMID: 24170365 DOI: 10.1002/smll.201300843] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 06/21/2013] [Indexed: 06/02/2023]
Abstract
A novel uniform amorphous carbon-coated SnO2 nanocrystal (NCs) for use in lithium-ion batteries is formed by utilizing bovine serum albumin (BSA) as both the ligand and carbon source. The SnO2 -carbon composite is then coated by a controlled thickness of polydopamine (PD) layer through in situ polymerization of dopamine. The PD-coated SnO2 -carbon composite is finally mixed with polyacrylic acid (PAA) which is used as binder to accomplish a whole anode system. A crosslink reaction is built between PAA and PD through formation of amide bonds to produce a robust network in the anode system. As a result, the designed electrode exhibits improved reversible capacity of 648 mAh/g at a current density of 100 mA/g after 100 cycles, and an enhanced rate performance of 875, 745, 639, and 523 mAh/g at current densities of 50, 100, 250, and 500 mA/g, respectively. FTIR spectra confirm the formation of crosslink reaction and the stability of the robust network during long-term cycling. The great improvement of capacity and rate performance achieved in this anode system is attributed to two stable interfaces built between the active material (SnO2 -carbon composite) and the buffer layer (PD) and between the buffer layer and the binder (PAA), which effectively diminish the volume change of SnO2 during charge/discharge process and provide a stable matrix for active materials.
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Affiliation(s)
- Lei Wang
- Key Laboratory of Synthesis and Natural Functional Molecular Chemistry (Ministry of Education), College of Chemistry & Materials Science Northwest University, Xi'an, Shaanxi, 710069, China; i-LAB and Nano-bionics Division Suzhou Institute of Nano-Tech & Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China
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581
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Wang L, Wu B, Chen J, Liu H, Hu P, Liu Y. Monolayer hexagonal boron nitride films with large domain size and clean interface for enhancing the mobility of graphene-based field-effect transistors. Adv Mater 2014; 26:1559-64. [PMID: 24343959 DOI: 10.1002/adma.201304937] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 10/28/2013] [Indexed: 05/06/2023]
Abstract
Viable and general techniques that allow effective size control of triangular-shaped, single-crystal, monolayer h-BN domains grown by the CVD method, direct optical visualization of h-BN domains, and the cleaning of the h-BN surface to achieve reliable graphene device quality are reported for the first time. This study points to a critical role of the interfacial properties between the graphene and the monolayer h-BN in determining reliable, enhanced graphene-device performance.
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Affiliation(s)
- Lifeng Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing, 100190, P. R. China; Key Lab of Microsystem and Microstructure, Harbin Institute of Technology, Harbin, 150080, P. R. China
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582
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Olive AGL, Abdullah NH, Ziemecka I, Mendes E, Eelkema R, van Esch JH. Spatial and directional control over self-assembly using catalytic micropatterned surfaces. Angew Chem Int Ed Engl 2014; 53:4132-6. [PMID: 24615796 DOI: 10.1002/anie.201310776] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Indexed: 01/03/2023]
Abstract
Catalyst-assisted self-assembly is widespread in nature to achieve spatial control over structure formation. Reported herein is the formation of hydrogel micropatterns on catalytic surfaces. Gelator precursors react on catalytic sites to form building blocks which can self-assemble into nanofibers. The resulting structures preferentially grow where the catalyst is present. Not only is a first level of organization, allowing the construction of hydrogel micropatterns, achieved but a second level of organization is observed among fibers. Indeed, fibers grow with their main axis perpendicular to the substrate. This feature is directly linked to a unique mechanism of fiber formation for a synthetic system. Building blocks are added to fibers in a confined space at the solid-liquid interface.
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Affiliation(s)
- Alexandre G L Olive
- Advanced Soft Matter Group, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft (The Netherlands)
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583
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Shiba K, Tagaya M, Samitsu S, Motozuka S. Frontispiece: Effective Surface Functionalization of Carbon Fibers for Fiber/Polymer Composites with Tailor-Made Interfaces. Chempluschem 2014; 79. [PMID: 31986593 DOI: 10.1002/cplu.201480271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Composites between carbon fibers (CFs) and heterogeneous materials have been widely studied and their fabrication techniques have been developed. However, their hydrophobic surfaces make it difficult to disperse CFs into hydrophilic resins, which results in weak junctions with ceramics. To develop high-strength composite fibers, it is important to design interfacial chemical bonds. Thus, surface-modification techniques of CFs have recently become the main focus and their interfaces have been characterized by various analytical methods. In this Minireview, various techniques that modify the CF surface by coating with inorganic polymers (metal oxide compounds) are highlighted, and the applications of novel nanocomposite fibers are also described. Furthermore, interfacial bonds between CFs and polymer resins are reviewed and discussed in terms of CF-reinforced plastics and their future prospects.
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Affiliation(s)
- Kota Shiba
- World Premier International Research Center, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
| | - Motohiro Tagaya
- Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)
| | - Sadaki Samitsu
- Polymer Materials Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
| | - Satoshi Motozuka
- Department of Mechanical Engineering, Gifu National College of Technology, 2236-2 Kamimakuwa, Motosu, Gifu 501-0495 (Japan)
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584
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Shiba K, Tagaya M, Samitsu S, Motozuka S. Effective Surface Functionalization of Carbon Fibers for Fiber/Polymer Composites with Tailor-Made Interfaces. Chempluschem 2014; 79:197-210. [PMID: 31986581 DOI: 10.1002/cplu.201300356] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Indexed: 11/08/2022]
Abstract
Composites between carbon fibers (CFs) and heterogeneous materials have been widely studied and their fabrication techniques have been developed. However, their hydrophobic surfaces make it difficult to disperse CFs into hydrophilic resins, which results in weak junctions with ceramics. To develop high-strength composite fibers, it is important to design interfacial chemical bonds. Thus, surface-modification techniques of CFs have recently become the main focus and their interfaces have been characterized by various analytical methods. In this Minireview, various techniques that modify the CF surface by coating with inorganic polymers (metal oxide compounds) are highlighted, and the applications of novel nanocomposite fibers are also described. Furthermore, interfacial bonds between CFs and polymer resins are reviewed and discussed in terms of CF-reinforced plastics and their future prospects.
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Affiliation(s)
- Kota Shiba
- World Premier International Research Center, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
| | - Motohiro Tagaya
- Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)
| | - Sadaki Samitsu
- Polymer Materials Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
| | - Satoshi Motozuka
- Department of Mechanical Engineering, Gifu National College of Technology, 2236-2 Kamimakuwa, Motosu, Gifu 501-0495 (Japan)
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585
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Yadian B, Liu H, Wei Y, Wu J, Zhang S, Sun L, Zhao C, Liu Q, Ramanujan RV, Zhou K, Gan CL, Huang Y. Towards perfectly ordered novel ZnO/Si nano-heterojunction arrays. Small 2014; 10:344-348. [PMID: 23881853 DOI: 10.1002/smll.201301674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 06/18/2013] [Indexed: 06/02/2023]
Abstract
The fabrication of a highly ordered novel ZnO/Si nano-heterojuntion array is introduced. ZnO seed layer is first deposited on the Si (P<111>) surface. The nucleation sites are then defined by patterning the surface through focused ion beam (FIB) system. The ZnO nanorods are grown on the nucleation sites through hydrothermal process. The whole fabrication process is simple, facile and offers direct control of the space, length and aspect ratio of the array. It is found that ZnO/Si nanojunctions show an improved interface when subjected to heat treatment. The recrystallization of ZnO and the tensile lattice strain of Si developed during the heating process contribute the enhancement of their photoresponses to white light. The photoluminescence (PL) measurement result of nano-heterojunction arrays with different parameters is discussed.
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Affiliation(s)
- Boluo Yadian
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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586
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Petraki F, Peisert H, Uihlein J, Aygül U, Chassé T. CoPc and CoPcF16 on gold: Site-specific charge-transfer processes. Beilstein J Nanotechnol 2014; 5:524-31. [PMID: 24991487 PMCID: PMC4077293 DOI: 10.3762/bjnano.5.61] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/10/2014] [Indexed: 05/09/2023]
Abstract
Interface properties of cobalt(II) phthalocyanine (CoPc) and cobalt(II) hexadecafluoro-phthalocyanine (CoPcF16) to gold are investigated by photo-excited electron spectroscopies (X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and X-ray excited Auger electron spectroscopy (XAES)). It is shown that a bidirectional charge transfer determines the interface energetics for CoPc and CoPcF16 on Au. Combined XPS and XAES measurements allow for the separation of chemical shifts based on different local charges at the considered atom caused by polarization effects. This facilitates a detailed discussion of energetic shifts of core level spectra. The data allow the discussion of site-specific charge-transfer processes.
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Affiliation(s)
- Fotini Petraki
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Johannes Uihlein
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Umut Aygül
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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587
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Mogal V, Papper V, Chaurasia A, Feng G, Marks R, Steele T. Novel on-demand bioadhesion to soft tissue in wet environments. Macromol Biosci 2013; 14:478-84. [PMID: 24293270 DOI: 10.1002/mabi.201300380] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 10/21/2013] [Indexed: 02/06/2023]
Abstract
Current methods of tissue fixation rely on mechanical-related technologies developed from the clothing and carpentry industries. Herein, a novel bioadhesive method that allows tuneable adhesion and is also applicable to biodegradable polyester substrates is described. Diazirine is the key functional group that allows strong soft tissue crosslinking and on-demand adhesion based on a free radical mechanism. Plasma post-irradiation grafting makes it possible to graft diazirine onto PLGA substrates. When the diazirine-PLGA films, placed on wetted ex vivo swine aortas, are activated with low intensity UV light, lap shear strength of up to 450 ± 50 mN cm(-2) is observed, which is one order of magnitude higher than hydrogel bioadhesives placed on similar soft tissues. The diazirine-modified PLGA thin films could be added on top of previously developed technologies for minimally invasive surgeries. The present work is focused on the chemistry, grafting, and lap shear strength of the alkyl diazirine-modified PLGA bioadhesive films.
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Affiliation(s)
- Vishal Mogal
- Materials and Science Engineering, Division of Materials Technology, Nanyang Technological University, Singapore, 639798
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588
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Vileno B, Turek P, Weiss J, Martel D. Windowsill Hydrogen Production under Daylight Irradiation. Chempluschem 2013; 78:1330-1333. [PMID: 31986639 DOI: 10.1002/cplu.201300201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/05/2013] [Indexed: 11/05/2022]
Abstract
Here comes the sun! Hydrogen can be produced on a windowsill under daylight irradiation of TiO2 -supported platinum by using a self-buffered electron-donor solution that optimizes the interfacial processes.
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Affiliation(s)
- Bertrand Vileno
- Propriétés Optiques et Magnétiques des Architectures, Moléculaires (POMAM), Institut de Chimie, UMR 7177 CNRS/Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg (France)
| | - Philippe Turek
- Propriétés Optiques et Magnétiques des Architectures, Moléculaires (POMAM), Institut de Chimie, UMR 7177 CNRS/Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg (France)
| | - Jean Weiss
- Chimie des Ligands à Architecture Contrôlée (CLAC), Institut de Chimie, UMR 7177 CNRS/Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg (France)
| | - David Martel
- Institut de Chimie, UMR 7177 CNRS/Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg (France).,Centre National de la Recherche Scientifique, UPR22, Institut Charles Sadron, 23 rue du lœss, BP 84047, 67034 Strasbourg cedex 2 (France)
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589
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Zhang YX, Hao XD, Kuang M, De Chen R. Interfacial polygonal patterning via surfactant-mediated self-assembly of gold nanoparticles. Nanoscale Res Lett 2013; 8:436. [PMID: 24144325 PMCID: PMC4015365 DOI: 10.1186/1556-276x-8-436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/09/2013] [Indexed: 06/02/2023]
Abstract
In this work, we explored the formation processes of interfacial polygonal patterning via surfactant-mediated self-assembly of gold nanoparticles (AuNPs). We found that a balance between DDT-capped AuNPs and PVP-passivated AuNPs is a key to making these inorganic-organic thin films. The interfacial polygonal patterning possesses many processing advantages and flexibilities, such as controllable interfacial shape and inter-AuNP distance, tuning of particle sizes, thiol population, chain lengths, and other new properties by introducing functional groups to thiol chains. In principle, self-assembly of AuNPs via well-designed interfaces may be useful for fabrications of other complex architectures.
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Affiliation(s)
- Yu Xin Zhang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, People’s Republic of China
- National Key Laboratory of Fundamental Science of Micro/Nano-Devices and System Technology, Chongqing University, Chongqing 400044, People’s Republic of China
| | - Xiao Dong Hao
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, People’s Republic of China
| | - Min Kuang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, People’s Republic of China
| | - Ru De Chen
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
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590
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Chen X, Zheng M, Park C, Ke C. Direct measurements of the mechanical strength of carbon nanotube-poly(methyl methacrylate) interfaces. Small 2013; 9:3345-3351. [PMID: 23606544 DOI: 10.1002/smll.201202771] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Indexed: 06/02/2023]
Abstract
Understanding the interfacial stress transfer between carbon nanotubes (CNTs) and polymer matrices is of great importance to the development of CNT-reinforced polymer nanocomposites. In this paper, an experimental study is presented of the interfacial strength between individual double-walled CNTs and poly(methyl methacrylate) (PMMA) using an in situ nanomechanical single-tube pull-out testing scheme inside a high-resolution electron microscope. By pulling out individual tubes with different embedded lengths, this work reveals the shear lag effect on the nanotube-polymer interface and demonstrates that the effective interfacial load transfer occurs only within a certain embedded length. These results show that the CNT-PMMA interface possesses an interfacial fracture energy within 0.054-0.80 J/m(2) and a maximum interfacial strength within 85-372 MPa. This work is useful to better understand the local stress transfer on nanotube-polymer interfaces.
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Affiliation(s)
- Xiaoming Chen
- Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, NY, 13902, USA
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591
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Wu Z, Dong C, Li Y, Hao H, Zhang H, Lu Z, Yang B. Self-assembly of Au15 into single-cluster-thick sheets at the interface of two miscible high-boiling solvents. Angew Chem Int Ed Engl 2013; 52:9952-5. [PMID: 24030896 DOI: 10.1002/anie.201304122] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 11/12/2022]
Abstract
Wet (nano)blanket: The self-assembly of Au nanoclusters into single-cluster-thick nanosheets is performed in two miscible high-boiling solvents with a slight polarity difference, which generates microphase separation and acts as a soft template to direct the self-assembly in a two-dimensional orientation.
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Affiliation(s)
- Zhennan Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 (P. R. China)
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592
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Liu XH, Wang D, Wan LJ. Surface tectonics of nanoporous networks of melamine-capped molecular building blocks formed through interface Schiff-base reactions. Chem Asian J 2013; 8:2466-70. [PMID: 23868669 DOI: 10.1002/asia.201300546] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/01/2013] [Indexed: 11/08/2022]
Abstract
Control over the assembly of molecules on a surface is of great importance for the fabrication of molecule-based miniature devices. Melamine (MA) and molecules with terminal MA units are promising candidates for supramolecular interfacial packing patterning, owing to their multiple hydrogen-bonding sites. Herein, we report the formation of self-assembled structures of MA-capped molecules through a simple on-surface synthetic route. MA terminal groups were successfully fabricated onto rigid molecular cores with 2-fold and 3-fold symmetry through interfacial Schiff-base reactions between MA and aldehyde groups. Sub-molecular scanning tunneling microscopy (STM) imaging of the resultant adlayer revealed the formation of nanoporous networks. Detailed structural analysis indicated that strong hydrogen-bonding interactions between the MA groups persistently drove the formation of nanoporous networks. Herein, we demonstrate that functional groups with strong hydrogen-bond-formation ability are promising building blocks for the guided assembly of nanoporous networks and other hierarchical 2D assemblies.
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Affiliation(s)
- Xuan-He Liu
- CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190 (P. R. China); Beijing National Laboratory for Molecular Sciences, Beijing 100190 (P. R. China), Fax: (+86) 10-62558934; Graduate University of CAS, Beijing 100490 (P. R. China)
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593
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Ohba T, Taira SI, Hata K, Kanoh H. Mechanism of Sequential Water Transportation by Water Loading and Release in Single-Walled Carbon Nanotubes. J Phys Chem Lett 2013; 4:1211-1215. [PMID: 26282044 DOI: 10.1021/jz400218s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Water in carbon nanotubes (CNTs) displays unique behaviors such as ring-like structure formation, anomalous hydrogen bonds, and fast transportation. We demonstrated the structures and stability of water in loading and release processes using a combination of X-ray diffraction analysis and hybrid reverse Monte Carlo simulations. Water formed nanoclusters in water loading, whereas layered structures were formed in water release. The water nanoclusters formed in water loading were well stabilized in CNTs. In contrast, in water release, the water layers were less stable than the water nanoclusters. The significant stabilization of nanoclusters in water loading and the relatively low stability of water layers in water release suggest easy water loading and release through CNTs, providing sequential water transportation through CNTs.
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Affiliation(s)
- Tomonori Ohba
- †Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
| | - Sei-Ichi Taira
- †Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
| | - Kenji Hata
- ‡Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi Tsukuba, Ibaraki 305-8565, Japan
| | - Hirofumi Kanoh
- †Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan
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594
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Sen A, Kupcho KA, Grinwald BA, VanTreeck HJ, Acharya BR. Liquid crystal-based sensors for selective and quantitative detection of nitrogen dioxide. Sens Actuators B Chem 2013; 178:222-227. [PMID: 23526230 PMCID: PMC3601936 DOI: 10.1016/j.snb.2012.12.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A highly sensitive nitrogen dioxide (NO2) sensor based on orientational transition of a thin film of liquid crystal (LC) supported on a gold surface is reported. Transport of NO2 molecules through the LC film to the LC-gold interface induces an orientation transition in the LC film. The dynamic behavior of the sensor response exhibits a concentration-dependent response rate that is employed to generate an algorithm for quantitative determination of unknown concentrations. Sensitive, selective and reversible detection with minimal effects of environmental fluctuations suggest that these sensors can be used for quantitative NO2 detection for a number of applications.
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595
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Abstract
We report a method for facile connection of a nickel bisdiphosphine-based functional mimic of the active site of hydrogenase to photocathodes that are relevant to artificial photosynthesis. This procedure exploits the UV-induced immobilization chemistry of alkenes to gallium phosphide and silicon surfaces. The photochemical grafting provides a means for patterning molecular linkers with attachment points to catalysts. Successful grafting is characterized by grazing angle attenuated total reflection Fourier transform infrared spectroscopy (GATR-FTIR), which shows catalyst vibrational modes, as well as X-ray photoelectron spectroscopy (XPS), which confirms the presence of intact Ni complex on the surface. The modular nature of this approach allows independent modification of the light absorber, bridging material, anchoring functionality, or catalyst as new materials and discoveries emerge.
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Affiliation(s)
- Gary F Moore
- Joint Center for Artificial Photosynthesis (JCAP), Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ian D Sharp
- Joint Center for Artificial Photosynthesis (JCAP), Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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596
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Kimmel AV, Íñiguez J, Cain MG, Sushko PV. Neutral and Charged Oxygen Vacancies Induce Two-Dimensional Electron Gas Near SiO2/BaTiO3 Interfaces. J Phys Chem Lett 2013; 4:333-337. [PMID: 26283444 DOI: 10.1021/jz301948k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An atomistic model of the SiO2/BaTiO3 interface was constructed using ab initio molecular dynamics. Analysis of its structure and electronic properties reveals that (i) the band gap at the stoichiometric SiO2/BaTiO3 interface is significantly smaller than those of the bulk BaTiO3 and SiO2, and (ii) the interface contains ∼5.5 nm(-2) oxygen vacancies (V(2+)) in the outermost TiO2 plane of the BaTiO3 and ∼11 nm(-2) Si-O-Ti bonds resulting from breaking Si-O-Si and Ti-O-Ti bonds and subsequent rearrangement of the atoms. This structure gives rise to the interface polar region with positive and negative charges localized in the BaTiO3 and SiO2 parts of the interface, respectively. We propose that high dielectric response, observed experimentally in the SiO2-coated nanoparticles of BaTiO3, is due to the electron gas formed in oxygen-deficient BaTiO3 and localized in the vicinity of the polar interface.
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Affiliation(s)
- Anna V Kimmel
- †Department of Physics and Astronomy and the London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, U.K
- ‡National Physical Laboratory, Teddington, TW11 0LW, U.K
| | - Jorge Íñiguez
- §Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), 08193 Bellaterra, Spain
| | - Markys G Cain
- ‡National Physical Laboratory, Teddington, TW11 0LW, U.K
| | - Peter V Sushko
- †Department of Physics and Astronomy and the London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, U.K
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597
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Wang J, Yu J, Zhu X, Kong XZ. Preparation of hollow TiO2 nanoparticles through TiO2 deposition on polystyrene latex particles and characterizations of their structure and photocatalytic activity. Nanoscale Res Lett 2012; 7:646. [PMID: 23176612 PMCID: PMC3533932 DOI: 10.1186/1556-276x-7-646] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 11/15/2012] [Indexed: 05/07/2023]
Abstract
In a mixed solvent of water and ethanol, polystyrene/titanium dioxide (PSt/TiO2) composite particles of core-shell structure were prepared by hydrolysis of tetrabutyl titanate in the presence of cationic PSt particles or anionic PSt particles surface-treated using γ-aminopropyl triethoxysilane. Hollow TiO2 particles were obtained through calcination of the PSt/TiO2 core-shell particles to burn off the PSt core or through dissolution of the core by tetrahydrofuran (THF). An alternative process constituted of preheating the PSt/TiO2 particles at 200°C to allow partial crystallization followed by calcination or PSt dissolution by THF. The outcome TiO2 particles thus prepared were examined by TEM, and hollow TiO2 particles were observed. The crystalline phase structure and phase transformation were characterized, which revealed that preheating before the removal of the PSt core was useful to achieve the desired hollow TiO2 particles, and the calcination process was beneficial to the formation of anatase and rutile structures. The tests of TiO2 particles as catalyst in the photodegradation of Rhodamine B demonstrated that a much higher catalytic activity was observed with the TiO2 hollow particles prepared through calcination combined with preheating.
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Affiliation(s)
- Jingang Wang
- College of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Jiemei Yu
- College of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Xiaoli Zhu
- College of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Xiang Zheng Kong
- College of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
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598
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Kaul I, Joshi N, Ballav N, Ghosh P. Hydrogenation of Ferrimagnetic Graphene on a Co Surface: Significant Enhancement of Spin Moments by C-H Functionality. J Phys Chem Lett 2012; 3:2582-2587. [PMID: 26295878 DOI: 10.1021/jz3010283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using ab initio density functional theory, we present a novel way of simultaneously enhancing the induced magnetic moment and opening up the band gap of a graphene sheet supported on ferromagnetic transition metal surface. Specifically, we have demonstrated that by simply hydrogenating graphene supported on ferromagnetic Co surface at saturation coverage, (i) there is a six-fold increase in the magnitude of the induced magnetic moment compared with the pristine graphene on the Co surface and (ii) for both the spin-up and the spin-down channels there is a band gap opening at the K-point of the Brillouin zone.
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Affiliation(s)
- Indu Kaul
- †Department of Chemistry and ‡Department of Physics, Indian Institute of Science Education and Research, Pune-411021, India
| | - Niharika Joshi
- †Department of Chemistry and ‡Department of Physics, Indian Institute of Science Education and Research, Pune-411021, India
| | - Nirmalya Ballav
- †Department of Chemistry and ‡Department of Physics, Indian Institute of Science Education and Research, Pune-411021, India
| | - Prasenjit Ghosh
- †Department of Chemistry and ‡Department of Physics, Indian Institute of Science Education and Research, Pune-411021, India
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599
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Kulik HJ, Schwegler E, Galli G. Probing the Structure of Salt Water under Confinement with First-Principles Molecular Dynamics and Theoretical X-ray Absorption Spectroscopy. J Phys Chem Lett 2012; 3:2653-2658. [PMID: 26295887 DOI: 10.1021/jz300932p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigated the structure of liquid water around cations (Na(+)) and anions (Cl(-)) confined inside of a (19,0) carbon nanotube with first-principles molecular dynamics and theoretical X-ray absorption spectroscopy (XAS). We found that the ions preferentially reside near the interface between the nanotube and the liquid. Upon confinement, the XAS signal of water molecules surrounding Na(+) exhibits enhanced pre-edge and reduced post-edge features with respect to that of pure water, at variance with the solvation shell of Na(+) in bulk water. Conversely, the first solvation shell of confined Cl(-) has a main-edge intensity comparable to that of bulk solvated Cl(-), likely as a result of a high number of acceptor hydrogen bonds in the first solvation shell. Confined nonsolvating water molecules exhibit bulk-like or water-monomer-like properties, depending on whether they belong to core or interfacial layers, respectively.
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Affiliation(s)
- Heather J Kulik
- †Department of Chemistry, Stanford University, 333 Campus Drive, Mudd Building Room 121, Stanford, California 94305, United States
| | - Eric Schwegler
- ‡Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, PO Box 808, L-415, Livermore, California 94550, United States
| | - Giulia Galli
- ¶Departments of Chemistry and Physics, University of California-Davis, One Shields Avenue, Davis, California 95618, United States
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600
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Liang YT, Vijayan BK, Lyandres O, Gray KA, Hersam MC. Effect of Dimensionality on the Photocatalytic Behavior of Carbon-Titania Nanosheet Composites: Charge Transfer at Nanomaterial Interfaces. J Phys Chem Lett 2012; 3:1760-5. [PMID: 26291856 DOI: 10.1021/jz300491s] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Due to their unique optoelectronic structure and large specific surface area, carbon nanomaterials have been integrated with titania to enhance photocatalysis. In particular, recent work has shown that nanocomposite photocatalytic performance can be improved by minimizing the covalent defect density of the carbon component. Herein, carbon nanotube-titania nanosheet and graphene-titania nanosheet composites with low carbon defect densities are compared to investigate the role of carbon nanomaterial dimensionality on photocatalytic response. The resulting 2D-2D graphene-titania nanosheet composites yield superior electronic coupling compared to 1D-2D carbon nanotube-titania nanosheet composites, leading to greater enhancement factors for CO2 photoreduction under ultraviolet irradiation. On the other hand, 1D carbon nanotubes are shown to be more effective titania photosensitizers, leading to greater photoactivity enhancement factors under visible illumination. Overall, this work suggests that carbon nanomaterial dimensionality is a key factor in determining the spectral response and reaction specificity of carbon-titania nanosheet composite photocatalysts.
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Affiliation(s)
- Yu Teng Liang
- †Department of Materials Science and Engineering, ‡Department of Civil and Environmental Engineering, §Department of Chemistry, and ⊥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Baiju K Vijayan
- †Department of Materials Science and Engineering, ‡Department of Civil and Environmental Engineering, §Department of Chemistry, and ⊥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Olga Lyandres
- †Department of Materials Science and Engineering, ‡Department of Civil and Environmental Engineering, §Department of Chemistry, and ⊥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Kimberly A Gray
- †Department of Materials Science and Engineering, ‡Department of Civil and Environmental Engineering, §Department of Chemistry, and ⊥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Materials Science and Engineering, ‡Department of Civil and Environmental Engineering, §Department of Chemistry, and ⊥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
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