1
|
Zhao W, Göthelid M, Hosseinpour S, Johansson MB, Li G, Leygraf C, Johnson CM. The nature of self-assembled octadecylphosphonic acid (ODPA) layers on copper substrates. J Colloid Interface Sci 2021; 581:816-825. [PMID: 32818682 DOI: 10.1016/j.jcis.2020.07.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 11/19/2022]
Abstract
HYPOTHESIS The self-assembly of amphiphilic molecules onto solid substrates can result both in the formation of monolayers and multilayers. However, on oxidized and non-oxidized copper (Cu), only monolayer formation was reported for phosphonic acids possessing one phosphate head group. Here, the adsorption of octadecylphosphonic acid (ODPA) on Cu substrates through a self-assembly process was investigated with the initial hypothesis of monolayer formation. EXPERIMENTS The relative amount of ODPA adsorbed on a Cu substrate was determined by infrared reflection/absorption spectroscopy (IRRAS) and by atomic force microscopy (AFM) investigations before and after ODPA deposition. X-ray photoelectron spectroscopy (XPS) with sputtering was used to characterize the nature of the layers. FINDINGS The results show that the thickness of the ODPA layer increased with deposition time, and after 1 h a multilayer film with a thickness of some tens of nm was formed. The film was robust and required long-time sonication for removal. The origin of the film robustness was attributed to the release of Cu ions, resulting in the formation of Cu-ODPA complexes with Cu ions in the form of Cu(I). Preadsorbing a monolayer of octadecylthiol (ODT) onto the Cu resulted in no ODPA adsorption, since the release of Cu(I) ions was abolished.
Collapse
Affiliation(s)
- Weijie Zhao
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - Mats Göthelid
- KTH Royal Institute of Technology, Department of Applied Physics, Material and Nano Physics, SE-164 40 Stockholm, Sweden.
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany.
| | - Malin B Johansson
- Department of Chemistry Ångström Laboratory, Division of Physical Chemistry, Uppsala University, SE-751 20 Uppsala, Sweden.
| | - Gen Li
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - Christofer Leygraf
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| | - C Magnus Johnson
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
| |
Collapse
|
2
|
Schulze-Zachau F, Braunschweig B. C nTAB/polystyrene sulfonate mixtures at air-water interfaces: effects of alkyl chain length on surface activity and charging state. Phys Chem Chem Phys 2019; 21:7847-7856. [PMID: 30916092 DOI: 10.1039/c9cp01107b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Binding and phase behavior of oppositely charged polyelectrolytes and surfactants with different chain lengths were studied in aqueous bulk solutions and at air-water interfaces. In particular, we have investigated the polyanion poly(sodium 4-styrenesulfonate) (NaPSS) and the cationic surfactants dodecyltrimethylammonium bromide (C12TAB), tetradecyltrimethylammonium bromide (C14TAB) and cetyltrimethylammonium bromide (C16TAB). In order to reveal the surfactant/polyelectrolyte binding, aggregation and phase separation of the mixtures, we have varied the NaPSS concentration systematically and have kept the surfactant concentration fixed at 1/6 of the respective critical micelle concentration. Information on the behavior in the bulk solution was gained by electrophoretic mobility and turbidity measurements, while the surface properties were studied using surface tension measurements and vibrational sum-frequency generation (SFG). This has enabled us to relate bulk to interfacial properties with respect to the charging state and the surfactants' binding efficiency. We found that the latter two are strongly dependent on the alkyl chain length of the surfactant and that binding is much more efficient as the alkyl chain length of the surfactant increases. This also results in a different phase behavior as shown by turbidity measurements of the bulk solutions. Charge neutral aggregates that are forming in the bulk adsorb onto the air-water interface - an effect that is likely caused by the increased hydrophobicity of CnTAB/PSS complexes. This conclusion is corroborated by SFG spectroscopy, where we observe a decrease in the intensity of O-H stretching bands, which is indicative of a decrease in surface charging and the formation of interfaces with negligible net charge. Particularly at mixing ratios that are in the equilibrium two-phase region, we observe weak O-H intensities and thus surface charging.
Collapse
Affiliation(s)
- Felix Schulze-Zachau
- Institute of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany.
| | | |
Collapse
|
3
|
Wang G, Huang K, Liu Z, Du Y, Wang X, Lu H, Zhang G, Qiu L. Flexible, Low-Voltage, and n-Type Infrared Organic Phototransistors with Enhanced Photosensitivity via Interface Trapping Effect. ACS APPLIED MATERIALS & INTERFACES 2018; 10:36177-36186. [PMID: 30264563 DOI: 10.1021/acsami.8b12009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Flexible and low-voltage near-infrared organic phototransistors (NIR OPTs) were prepared with a low-band gap donor-acceptor conjugated polymer as the semiconductor layer and n-octadecyl phosphonic acid modified anodic alumina (AlO x/ODPA) as the insulating layer. The phototransistors exhibit the typical n-type transistor characteristics at a voltage below 5 V. The photosensitivity of phototransistors can be enhanced by regulating the packing densities of the ODPA self-assembled monolayers and forming different trap states. The enhanced OPTs exhibit good photosensitivity to 808-980 nm NIR with the photocurrent/dark current ratio and photoresponsivity as high as 5 × 103 and 20 mA W-1, respectively, benefiting from the charge-trapping effect at the AlO x/ODPA interface. The OPTs also present a fast optical switching speed of 20/30 ms and an excellent mechanical flexibility. The outstanding performance of the NIR OPTs indicates that the development of wearable electronics is, indeed, possible.
Collapse
|
4
|
Meltzer C, Yu H, Peukert W, Braunschweig B. Molecular structure of octadecylphosphonic acids during their self-assembly on α-Al2O3(0001). Phys Chem Chem Phys 2018; 20:19382-19389. [DOI: 10.1039/c8cp02391c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation of octadecylphosphonic acid (ODPA) self-assembled monolayers (SAMs) from 2-propanol solutions on hydroxylated α-Al2O3(0001) surfaces was studied in situ and in real time at the solid/liquid interface.
Collapse
Affiliation(s)
- Christian Meltzer
- Institute of Particle Technology (LFG) and Cluster of Excellence – Engineering of Advanced Materials (EAM)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- Erlangen 91058
- Germany
| | - Hui Yu
- Institute of Particle Technology (LFG) and Cluster of Excellence – Engineering of Advanced Materials (EAM)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- Erlangen 91058
- Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG) and Cluster of Excellence – Engineering of Advanced Materials (EAM)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- Erlangen 91058
- Germany
| | - Björn Braunschweig
- Institute of Physical Chemistry and Center for Soft Nanoscience (SoN)
- Westfälische Wilhelms University Münster
- Münster 48149
- Germany
| |
Collapse
|
5
|
Pathak A, Bora A, Braunschweig B, Meltzer C, Yan H, Lemmens P, Daum W, Schwartz J, Tornow M. Nanocylindrical confinement imparts highest structural order in molecular self-assembly of organophosphonates on aluminum oxide. NANOSCALE 2017; 9:6291-6295. [PMID: 28485443 DOI: 10.1039/c7nr02420g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the impact of geometrical constraint on intramolecular interactions in self-assembled monolayers (SAMs) of alkylphosphonates grown on anodically oxidized aluminum (AAO). Molecular order in these films was determined by sum frequency generation (SFG) spectroscopy, a more sensitive measure of order than infrared absorption spectroscopy. Using SFG we show that films grown on AAO are, within detection limits, nearly perfectly ordered in an all-trans alkyl chain configuration. In marked contrast, films formed on planar, plasma-oxidized aluminum oxide or α-Al2O3 (0001) are replete with gauche defects. We attribute these differences to the nanocylindrical structure of AAO, which enforces molecular confinement.
Collapse
Affiliation(s)
- Anshuma Pathak
- Institut für Halbleitertechnik, TU Braunschweig, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Dietrich H, Schmaltz T, Halik M, Zahn D. Molecular dynamics simulations of phosphonic acid–aluminum oxide self-organization and their evolution into ordered monolayers. Phys Chem Chem Phys 2017; 19:5137-5144. [DOI: 10.1039/c6cp08681k] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We outline an unprejudiced molecular dynamics simulation approach to study the mechanisms of self-organization encompassing the evolution of surfactant–surface interactions to the growth of self-assembled monolayers (SAMs).
Collapse
Affiliation(s)
- H. Dietrich
- Computer Chemie Centrum & Chair of Theoretical Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91052 Erlangen
- Germany
| | - T. Schmaltz
- Organic Materials & Devices (OMD)
- Institute of Polymer Materials
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - M. Halik
- Organic Materials & Devices (OMD)
- Institute of Polymer Materials
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91058 Erlangen
- Germany
| | - D. Zahn
- Computer Chemie Centrum & Chair of Theoretical Chemistry
- Friedrich-Alexander-Universität Erlangen-Nürnberg
- 91052 Erlangen
- Germany
| |
Collapse
|
7
|
Paul J, Meltzer C, Braunschweig B, Peukert W. Lubrication of Individual Microcontacts by a Self-Assembled Alkyl Phosphonic Acid Monolayer on α-Al2O3(0001). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8298-8306. [PMID: 27478898 DOI: 10.1021/acs.langmuir.6b01933] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on the tribological behavior of a self-assembled alkyl phosphonic acid monolayer on the microscale using the colloidal probe technique. Friction-load data and adhesion forces were measured with borosilicate glass particles on uncoated and octadecylphosphonic acid (ODPA) coated α-Al2O3(0001) surfaces. A significant decrease in friction force was observed after surface coating, while the adhesion force was only moderately reduced. We assume the lubrication effect of the ODPA self-assembled monolayer (SAM) to be close to the maximum obtainable of alkyl phosphonic acids in the studied system due to the high molecular order which was confirmed by vibrational sum-frequency generation. At small loads, a nonlinear dependence of friction force to load was maintained after surface coating. However, a shift from a contact behavior well described by the DMT model toward the JKR model occurred that is possibly related to the altered elastic properties of the coated surface. With increasing load, a linear friction-load behavior was observed on the coated samples. Molecular plowing and adhesive interactions were identified as responsible mechanisms. In all friction experiments, we could not detect any wear neither of the colloidal probes nor at the surfaces of uncoated and coated samples. This proves the high wear resistivity of the studied ODPA SAM.
Collapse
Affiliation(s)
- Jonas Paul
- Institute of Particle Technology (LFG), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Cauerstraße 4, 91058 Erlangen, Germany
| | - Christian Meltzer
- Institute of Particle Technology (LFG), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Cauerstraße 4, 91058 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
| | - Björn Braunschweig
- Institute of Particle Technology (LFG), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Cauerstraße 4, 91058 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
- Cluster of Excellence - Engineering of Advanced Materials (EAM), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Nägelsbachstrasse 49b, 91052 Erlangen, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Cauerstraße 4, 91058 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
- Cluster of Excellence - Engineering of Advanced Materials (EAM), Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Nägelsbachstrasse 49b, 91052 Erlangen, Germany
| |
Collapse
|
8
|
Paniagua SA, Giordano AJ, Smith OL, Barlow S, Li H, Armstrong NR, Pemberton JE, Brédas JL, Ginger D, Marder SR. Phosphonic Acids for Interfacial Engineering of Transparent Conductive Oxides. Chem Rev 2016; 116:7117-58. [DOI: 10.1021/acs.chemrev.6b00061] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergio A. Paniagua
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Anthony J. Giordano
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - O’Neil L. Smith
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Stephen Barlow
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Hong Li
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Division
of Physical Sciences and Engineering, King Abdullah University of Science and Technology, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Neal R. Armstrong
- Department
of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jeanne E. Pemberton
- Department
of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jean-Luc Brédas
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Division
of Physical Sciences and Engineering, King Abdullah University of Science and Technology, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - David Ginger
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Seth R. Marder
- School
of Chemistry and Biochemistry and Center for Organic Photonics and
Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| |
Collapse
|
9
|
Bitsch B, Braunschweig B, Willenbacher N. Interaction between Polymeric Additives and Secondary Fluids in Capillary Suspensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1440-1449. [PMID: 26807658 DOI: 10.1021/acs.langmuir.5b03861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Capillary suspensions are ternary systems including a solid and two liquid phases representing a novel formulation platform for pastes with unique processing and end-use properties. Here we have investigated aqueous suspensions of non-Brownian graphite particles including different polymers commonly used as thickening agents or binders in paste formulations. We have studied the interaction between these additives and organic solvents in order to elucidate its effect on the characteristic formation of a particle network structure in corresponding ternary capillary suspension systems. Organic solvents with different polarity have been employed, and in the presence of nonadsorbing poly(ethylene oxide), all of them, whether they preferentially wet the graphite surface or not, induce the formation of a network structure within the suspension as indicated by a strong change in rheological properties. However, when the adsorbing polymers carboxymethylcellulose and poly(vinylpyrrolidone) are included, the drastic change in rheological behavior occurs only when polar organic solvents are used as secondary liquids. Obviously, these solvents can form pendular bridges, finally resulting in a sample-spanning particle network. Vibrational sum frequency spectroscopy provides evidence that these polar liquids remove the adsorbed polymer from the graphite particles. In contrast, nonpolar and nonwetting solvents do not force polymer desorption. In these cases, the formation of a percolating network structure within the suspensions is presumably prevented by the strong steric repulsion among graphite particles, not allowing for the formation of particle clusters encapsulating the secondary liquid. Accordingly, polymeric additives and secondary fluids have to be carefully selected in capillary suspension formulations, then offering a new pathway to customize paste formulations. The polymer may serve to adjust an appropriate viscosity level, and the capillary bridging induces the desired degree of shear thinning. Alternatively, the polymer may be selected with respect to its binding properties in the final dry product, and capillary bridging may be used to control the flow and processing behavior of the wet paste.
Collapse
Affiliation(s)
- Boris Bitsch
- Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology (KIT) , Gotthard-Franz-Strasse 3, 76131 Karlsruhe, Germany
| | - Björn Braunschweig
- Institute of Particle Technology (LFG), Friedrich-Alexander University Erlangen-Nürnberg (FAU) , Cauerstrasse 4, 91058 Erlangen, Germany
| | - Norbert Willenbacher
- Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology (KIT) , Gotthard-Franz-Strasse 3, 76131 Karlsruhe, Germany
| |
Collapse
|
10
|
Dietrich H, Scheiner S, Portilla L, Zahn D, Halik M. Improving the Performance of Organic Thin-Film Transistors by Ion Doping of Ethylene-Glycol-Based Self-Assembled Monolayer Hybrid Dielectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:8023-8027. [PMID: 26524344 DOI: 10.1002/adma.201503911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/29/2015] [Indexed: 06/05/2023]
Abstract
Tuning the electrostatics of ethylene-glycol-based self-assembled monolayers (SAMs) by doping with ions is shown. Molecular dynamics simulations unravel binding mechanisms and predict dipole strengths of the doped layers. Additionally, by applying such layers as dielectrics in organic thin-film transistors, the incorporated ions are proven to enhance device performance by lowering the threshold voltage and increasing conductivity.
Collapse
Affiliation(s)
- Hanno Dietrich
- Theoretical Chemistry and Computer-Chemistry-Center (CCC), FAU Erlangen-Nürnberg, Nägelsbachstraße, 25, 91052, Erlangen, Germany
| | - Simon Scheiner
- Organic Materials & Devices (OMD), Institute of Polymer Materials, FAU Erlangen-Nürnberg, Martensstraße, 7, 91058, Erlangen, Germany
| | - Luis Portilla
- Organic Materials & Devices (OMD), Institute of Polymer Materials, FAU Erlangen-Nürnberg, Martensstraße, 7, 91058, Erlangen, Germany
| | - Dirk Zahn
- Theoretical Chemistry and Computer-Chemistry-Center (CCC), FAU Erlangen-Nürnberg, Nägelsbachstraße, 25, 91052, Erlangen, Germany
| | - Marcus Halik
- Organic Materials & Devices (OMD), Institute of Polymer Materials, FAU Erlangen-Nürnberg, Martensstraße, 7, 91058, Erlangen, Germany
| |
Collapse
|