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Sauter E, Nascimbeni G, Trefz D, Ludwigs S, Zojer E, von Wrochem F, Zharnikov M. A dithiocarbamate anchoring group as a flexible platform for interface engineering. Phys Chem Chem Phys 2019; 21:22511-22525. [PMID: 31588446 DOI: 10.1039/c9cp03306h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular organization and electronic properties of dithiocarbamate (DTC) anchored self-assembled monolayers (SAMs) linked to Au(111) substrates are studied by a combination of X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and state-of-the-art density functional theory calculations. For that, several piperidine/piperazine precursors with different architecture and substitution patterns are selected. The presented data show that the DTC anchor provides a useful building block for monomolecular self-assembly on coinage metals with both sulfur atoms bonded to the substrate in a way similar to what is usually observed for the more commonly applied thiolate docking group. The combination of the DTC group with the quite flexible piperidine/piperazine cyclic linkers results in a dense molecular packing with an upright orientation of the terminal moieties. The latter comprise phenyl rings bearing various substituents, which enables tuning the interfacial dipole over a wide range. Simulations on two prototypical DTC-docked SAMs help to better understand the experimental observations and provide insight into the local origin of the SAM-induced shifts in the electrostatic energy. In particular, a comparison of measured and simulated XP spectra reveals the significant contribution of the DTC group to the interfacial dipole.
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Affiliation(s)
- Eric Sauter
- Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
| | - Giulia Nascimbeni
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Daniel Trefz
- Chair for Structure and Properties of Polymeric Materials, Institute of Polymer Chemistry (IPOC), University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Sabine Ludwigs
- Chair for Structure and Properties of Polymeric Materials, Institute of Polymer Chemistry (IPOC), University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Egbert Zojer
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Florian von Wrochem
- Institute of Materials Science, University of Stuttgart, Heisenbergstr. 3, 70569 Stuttgart, Germany.
| | - Michael Zharnikov
- Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
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Yang SC, Chen CY, Wan HY, Huang SY, Yang TI. Electroactive Composites with Block Copolymer-Templated Iron Oxide Nanoparticles for Magnetic Hyperthermia Application. Polymers (Basel) 2019; 11:E1430. [PMID: 31480428 PMCID: PMC6780777 DOI: 10.3390/polym11091430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 08/29/2019] [Accepted: 08/29/2019] [Indexed: 02/01/2023] Open
Abstract
Cancer has been one of the leading causes of human death for centuries. Magnetic hyperthermia is a promising technique to confine and control cancers. However, particles used in magnetic hyperthermia leaking from where the cancers are located could compromise human health. Therefore, we developed electroactive iron oxide/block copolymer composites to tackle the leakage problem. Experimental results show that oleylamine-modified magnetic iron oxide (Fe3O4) particles and electroactive tetraaniline (TA) could be templated in the self-assembled microstructures of sulfonated [styrene-b-(ethylene-ran-butylene)-b-styrene] (S-SEBS) block copolymers. Various amounts of Fe3O4 particles and TA oligomer were incorporated in S-SEBS block copolymer and their electroactive behavior was confirmed by exhibiting two pairs of well-defined anodic and cathodic current peaks in cyclic voltammetry tests. The heating performance of the resultant TA/Fe3O4/polymer composites improved on increasing the added amount of Fe3O4 particles and TA oligomers. Both Fe3O4 and TA can contribute to improved heating performance, but Fe3O4 possesses a greater contribution than TA does. Hence, the main source for increasing the composites' temperature is Neel relaxation loss from Fe3O4 magnetic particles.
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Affiliation(s)
- Shu-Chian Yang
- Department of Chemical Engineering, Chung-Yuan Christian University, Taoyuan 330, Taiwan
| | - Chun-Yu Chen
- Department of Chemical Engineering, Chung-Yuan Christian University, Taoyuan 330, Taiwan
| | - Hung-Yu Wan
- Department of Chemical Engineering, Chung-Yuan Christian University, Taoyuan 330, Taiwan
| | - Szu-Ying Huang
- Department of Chemical Engineering, Chung-Yuan Christian University, Taoyuan 330, Taiwan
| | - Ta-I Yang
- Department of Chemical Engineering, Chung-Yuan Christian University, Taoyuan 330, Taiwan.
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Lin CW, Li RL, Robbennolt S, Yeung MT, Akopov G, Kaner RB. Furthering Our Understanding of the Doping Mechanism in Conjugated Polymers Using Tetraaniline. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00633] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Cheng-Wei Lin
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Rebecca L. Li
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Shauna Robbennolt
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Michael T. Yeung
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Georgiy Akopov
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Richard B. Kaner
- Department
of Chemistry and Biochemistry and California NanoSystems
Institute and ‡Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
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Meyer D, Schäfer T, Schulz P, Jung S, Rittich J, Mokros D, Segger I, Maercks F, Effertz C, Mazzarello R, Wuttig M. Dithiocarbamate Self-Assembled Monolayers as Efficient Surface Modifiers for Low Work Function Noble Metals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8812-8817. [PMID: 27504721 DOI: 10.1021/acs.langmuir.6b01578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Tuning the work function of the electrode is one of the crucial steps to improve charge extraction in organic electronic devices. Here, we show that N,N-dialkyl dithiocarbamates (DTC) can be effectively employed to produce low work function noble metal electrodes. Work functions between 3.1 and 3.5 eV are observed for all metals investigated (Cu, Ag, and Au). Ultraviolet photoemission spectroscopy (UPS) reveals a maximum decrease in work function by 2.1 eV as compared to the bare metal surface. Electronic structure calculations elucidate how the complex interplay between intrinsic dipoles and dipoles induced by bond formation generates such large work function shifts. Subsequently, we quantify the improvement in contact resistance of organic thin film transistor devices with DTC coated source and drain electrodes. These findings demonstrate that DTC molecules can be employed as universal surface modifiers to produce stable electrodes for electron injection in high performance hybrid organic optoelectronics.
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Affiliation(s)
- Dominik Meyer
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Tobias Schäfer
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Philip Schulz
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States
- National Center for Photovoltaics, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Sebastian Jung
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Julia Rittich
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Daniel Mokros
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Ingolf Segger
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Franziska Maercks
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | - Christian Effertz
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
| | | | - Matthias Wuttig
- I. Institute of Physics (IA), ‡Institute for Theoretical Solid State Physics, and §JARA-Fundamentals of Future Information Technology, RWTH Aachen University , 52056 Aachen, Germany
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Kretz B, Egger DA, Zojer E. A Toolbox for Controlling the Energetics and Localization of Electronic States in Self-Assembled Organic Monolayers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2015; 2:1400016. [PMID: 27547707 PMCID: PMC4973851 DOI: 10.1002/advs.201400016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/27/2015] [Indexed: 05/28/2023]
Abstract
Controlling the nature of the electronic states within organic layers holds the promise of truly molecular electronics. To achieve that we, here, develop a modular concept for a versatile tuning of electronic properties in organic monolayers and their interfaces. The suggested strategy relies on directly exploiting collective electrostatic effects, which emerge naturally in an ensemble of polar molecules. By means of quantum-mechanical modeling we show that in this way monolayer-based quantum-cascades and quantum-well structures can be realized, which allow a precise control of the local electronic structure and the localization of electronic states. Extending that concept, we furthermore discuss strategies for activating spin sensitivity in specific regions of an organic monolayer.
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Affiliation(s)
- Bernhard Kretz
- Institute of Solid State Physics, NAWI Graz Graz University of Technology Petersgasse 16 A-8010 Graz Austria
| | - David A Egger
- Institute of Solid State Physics, NAWI Graz Graz University of Technology Petersgasse 16A-8010 Graz Austria; Department of Materials and Interfaces Weizmann Institute of Science Rehovoth 76100 Israel
| | - Egbert Zojer
- Institute of Solid State Physics, NAWI Graz Graz University of Technology Petersgasse 16 A-8010 Graz Austria
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Schlicke H, Herrmann C. Controlling Molecular Conductance: Switching Off π Sites through Protonation. Chemphyschem 2014; 15:4011-8. [DOI: 10.1002/cphc.201402561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Indexed: 11/06/2022]
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Weber I, Mallick B, Schild M, Kareth S, Puchta R, van Eldik R. Behavior of highly diluted electrolytes in strong electric fields-prevention of alumina deposition on grading electrodes in HVDC transmission modules by CO2-induced pH-control. Chemistry 2014; 20:12091-103. [PMID: 25110988 DOI: 10.1002/chem.201400165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Indexed: 11/06/2022]
Abstract
Alumina deposition on platinum grading electrodes in high voltage direct current (HVDC) transmission modules is an unsolved problem that has been around for more than three decades. This is due to the unavoidable corrosion of aluminum heat sinks that causes severe damage to electrical power plants and losses in the range of a million Euro range per day in power outage. Simple experiments in a representative HV test setup showed that aluminates at concentrations even below 10(-8) mol L(-1) can deposit on anodes through neutralization by protons produced in de-ionized water (κ≤0.15 μS cm(-1)) at 20-35 kV (8 mA) per electrode. In this otherwise electrolyte-poor aqueous environment, the depositions are formed three orders of magnitude below the critical precipitation concentration at pH 7! In the presence of an inert electrolyte such as TMAT (tetramethylammonium-p-toluenesulfonate), at a concentration level just above that of the total dissolved aluminum, no deposition was observed. Deposition can be also prevented by doping with CO2 gas at a concentration level that is magnitudes lower than that of the dissolved aluminum. From an overview of aqueous aluminum chemistry, the mystery of the alumina deposition process and its inhibition by CO2 is experimentally resolved and fully explained by field accumulation and repulsion models in synergism with acid-base equilibria. The extraordinary size of the alumina depositions is accounted for in terms of proton tunneling through "hydrated" alumina, which is supported by quantum chemical calculations. As a consequence, pulse-purging with pure CO2 gas is presented as a technical solution to prevent the deposition of alumina.
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Affiliation(s)
- Immo Weber
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstrasse 1, 91058 Erlangen (Germany), Fax: (+49) 9131-8527387.
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Wu Y, Liu S, Tao Y, Ma C, Zhang Y, Xu J, Wei Y. New strategy for controlled release of drugs. Potential pinpoint targeting with multiresponsive tetraaniline diblock polymer vesicles: site-directed burst release with voltage. ACS APPLIED MATERIALS & INTERFACES 2014; 6:1470-1480. [PMID: 24450985 DOI: 10.1021/am404696u] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A series of amphiphlic diblock polymers, tetraaniline block with different length of poly(N-isopropylacrylamide) (TA-b-PNIPAM), have been successfully synthesized. In a suitable solution, the as-synthesized diblock polymers can form stable large compound vesicles (LCVs) with multiple bimolecular-layer structure through self-assembly. These factors, such as the block length, different organic solvent, solvent ratio, pH value, temperature, and voltage, which affect the morphology and properties of the assembled aggregates, are systematically investigated. When the degree of polymerization of PNIPAM block is close to 10, the as-synthesized diblock polymer may form stable LCVs with the uniform size as well as few defects in the mixed solvent of dimethylformamide/water (v/v = 3:7). The assembled LCVs possess the properties of triple-responsive capacity on temperature, pH, and voltage. Variation in any of these factors can cause some changes in the morphology of LCVs. The drug release properties for doxorubicin (DOX) loaded by LCVs affected by temperature, voltage, and different pH values have been investigated. It is interesting that the structure of LCVs can be destructed completely by applying a voltage at 0.6 V. With such an advantage, the drugs loaded by the LCVs could burst release into designated place by using appropriate circuit design or instrument, thus achieving maximum efficacy of the loaded drugs or other bioactive molecules without any unnecessary chemical substances added. This approach allows us to concentrate more on material design aspects only, without regard to the complex targeting issue which is the biggest obstacle of such materials in practical applications.
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Affiliation(s)
- Yupeng Wu
- PCFM Lab, School of Chemistry and Chemical Engineering, Sun Yat-sen University , Guangzhou 51025, China
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Huang H, Li W, Wang H, Zeng X, Wang Q, Yang Y. Conducting hydrogels of tetraaniline-g-poly(vinyl alcohol) in situ reinforced by supramolecular nanofibers. ACS APPLIED MATERIALS & INTERFACES 2014; 6:1595-1600. [PMID: 24443880 DOI: 10.1021/am4043799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Novel conducting hydrogels (PVA-TA) with dual network structures were synthesized by the grafting reaction of tetraaniline (TA) into the main chains of poly(vinyl alcohol) and in situ reinforced by self-assembly of a sorbitol derivative as the gelator. The chemical structure of the PVA-TA hydrogels was characterized by using FT-IR and NMR. The mechanical strength of the PVA-TA hydrogels was strongly improved due to the presence of supramolecular nanofibers. For instance, the compressive and tensile strengths of supramolecular nanofiber-reinforced hydrogels were, respectively, 10 times and 5 times higher than those of PVA-TA hydrogels. Their storage modulus (G') and loss modulus (G″) were 5 times and 21 times higher than those of PVA-TA hydrogels, respectively. Cyclic voltammetry and conductivity measurements indicated that the electroactivity of reinforced hydrogels is not influenced by the presence of supramolecular nanofibers.
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Affiliation(s)
- Huabo Huang
- Key Laboratory for Large-Format Battery Materials and Systems, Ministry of Education, and ‡School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
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Djukic B, Lough AJ, Seferos DS. A Highly Electron-Deficient Analogue of Aniline, Soluble Oligomers, and Their Redox Properties. J Org Chem 2013; 78:9340-4. [DOI: 10.1021/jo401565f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Brandon Djukic
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto,
Ontario, M5S 3H6, Canada
| | - Alan J. Lough
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto,
Ontario, M5S 3H6, Canada
| | - Dwight S. Seferos
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto,
Ontario, M5S 3H6, Canada
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