SIMS2015 Session SI1-TuM: Surface & Interface Analysis

Tuesday, September 15, 2015 10:00 AM in Room Grand Crescent
Tuesday Morning

Time Period TuM Sessions | Abstract Timeline | Topic SI Sessions | Time Periods | Topics | SIMS2015 Schedule

Start Invited? Item
10:00 AM SI1-TuM-1 SIMS as a Method for Probing Stability of Chemical Bonds at the Molecule-Metal Interface
Jakub Ossowski, Jakub Rysz (Jagiellonian University, Poland); Mariusz Krawiec (Maria Curie Sklodowska University, Poland); Zbigniew Postawa (Jagiellonian University, Poland); Andreas Terfort (Goethe University, Germany); Piotr Cyganik (Jagiellonian University, Poland)

Self-Assembled Monolayers (SAMs) comprise a broadly applied nanotechnological system, in which molecules are chemically bonded to a substrate in an ordered and oriented fashion. The influence of the strength of the molecule-substrate bond on the structure and stability of SAMs are still poorly understood even for the most simple system of methanethiol on Au(111). While it is a common concept in chemistry that strengthening of one bond results in weakening of the adjacent ones, no results have been published if and how this effect protrudes further into the molecular backbone. By binding molecules to a surface in a form of SAMs, the strength of a primary bond can be selectively altered. Here, we report that by using static SIMS, we are able to observe for the first time positional oscillations in stability of consecutive bonds along the adsorbed molecule, with the amplitudes diminishing with increasing distance from the molecule-metal interface. To explain these observations, we have performed molecular dynamics simulations and density functional theory calculations. Our calculations show that the observed oscillation effects in chemical bond stability have a very general nature in chemistry related to breaking the translational symmetry in molecules. In the talk we will discuss two experiments. In the first experiment [1] as a model SAMs for SIMS analysis we have selected two homologous series of biphenyl substituted alkanethiols, for which either sulphur atoms (BPnS) or selenium atoms (BPnSe) act as a binding groups to the Au(111) substrate. In the second experiment [2] we use this SIMS approach for the analysis of purely aromatic SAMs/Au(111) based on naphthalene.

[1] Ossowski et al. „Oscillations in Stability of Consecutive Chemical Bonds Revealed by Ion-Induced Desorption” Angew. Chem. Int. Ed.2015, 54, 1336-1340.

[2] Ossowski et al. „Thiolate versus Selenolate: Structure, Stability and Charge Transfer Properties” ACS Nano, 2015, 9, 4508-4526.

10:20 AM SI1-TuM-2 The Planar Chemistry and Atomic Interdiffusion at Atomically Thin Interfaces
Andrei Dolocan (University of Texas at Austin)

Vertical heterostructures composed of ultra-thin films are an intense area of research due to their unique properties that result from structural planar confinement. Interfaces play a fundamental role in device performance, therefore requiring characterization tools that are both in-depth chemically selective and surface-morphology sensitive. Here, we propose a characterization methodology combining (micro-)Raman spectroscopy, atomic force microscopy (AFM) and time of flight secondary ion mass spectrometry (TOF-SIMS) to provide structural information, morphology, and planar chemical composition at virtually the atomic level, aimed specifically at studying ultra-thin vertical heterostructures. We give a general overview of the strength of this technique when applied to various devices that are linked to solar cells1, hydrogen catalysis2, copper interconnects3 and two dimensional vertical heterostructures4.

References

1. Jeramy D. Zimmerman, Brian E. Lassiter, Xin Xiao, Kai Sun, Andrei Dolocan, Raluca Gearba, David A. Vanden Bout, Keith J. Stevenson, Piyumie Wickramasinghe, Mark E. Thompson, and Stephen R. Forrest, “Control of Interface Order by Inverse Quasi-Epitaxial Growth of Squaraine/Fullerene Thin Film Photovoltaics”, ACS Nano 7, 9268 (2013).

2. Sean P. Berglund, Huichao He, William D. Chemelewski, Hugo Celio, Andrei Dolocan, and C. Buddie Mullins, “p‑Si/W2C and p‑Si/W2C/Pt Photocathodes for the Hydrogen Evolution Reaction”, Journal of the American Chemical Society 136, 1535 (2014).

3. Tyler D.-M. Elko-Hansen, Andrei Dolocan, and John G. Ekerdt, “Atomic Interdiffusion and Diffusive Stabilization of Cobalt by Copper During Atomic Layer Deposition from Bis(N-tert-butyl-N′-ethylpropionamidinato) Cobalt(II)”, The Journal of Physical Chemistry Letters 5 (7), 1091 (2014).

4. Harry Chou, Ariel Ismach, Rudresh Ghosh, Rodney S. Ruoff, and Andrei Dolocan, “Revealing the Planar Chemistry of Two-Dimensional Heterostructures at the Atomic Level”Nature Communications 6, 7482 (2015).
10:40 AM SI1-TuM-3 High-throughput Production of Transition Metal Complexes for Antibody Immobilization
Nicholas Welch (La Trobe University, Australia); Judy Scoble, Chris Easton (CSIRO, Manufacturing Flagship); Robert Madiona, Robert Jones (La Trobe University); Paul Pigram (La Trobe University, Australia); Benjamin Muir (CSIRO, Manufacturing Flagship)
High-throughput methodology was employed to produce chromium (III) complexes suitable for surface modification of a commercially available 96 well plate. The complexes were immobilized to the native functionality of the well plate and first screened using a horse radish peroxidase-tagged (HRP) antibody to quantify binding. The top “hits” were further assessed for their ability to present the antibody in a functional state using an enzyme-linked immunosorbent assay (ELISA). “Hits” from the second screen yielded four complexes capable of improving the signal intensity of the ELISA by greater than 500%. The metal:ligand ratio of these complexes was also investigated isolating the most reproducible candidate; chromium (III) perchlorate hexahydrate ethylene diamine. Surface modification protocols and bound species were investigated using ToF-SIMS and XPS to confirm the factors underlying improved ELISA performance.
11:00 AM SI1-TuM-4 Correlation of Pressure Sensitive Adhesive Performance with Surface Chemistry
Michaeleen Pacholski, Laura Donkus (The Dow Chemical Company)
Pressure sensitive adhesive (PSA) performance is influenced by surface and bulk properties. Adhesive properties of peel and tack are most strongly influenced by surface chemistry. The intimate contact of the top layer of the adhesive with the substrate can dominate the adhesive performance to a strong degree making it challenging to use conventional techniques like IR to characterize the chemistry driving performance. Here, we present an investigation of good and poor performing adhesives using SIMS. The surface sensitive nature of the technique was well suited for studying subtle surface variations between the samples and linked surface oxidation with poor adhesive performance.
11:20 AM SI1-TuM-5 Selective SAM Formation on Similar Metal Oxide Surfaces – ZrO2 and TiO2
Manuela Killian, Andreas Finger, Robert Hahn, Ole Pfoch, Patrik Schmuki (Friedrich-Alexander-University Erlangen-Nuernberg, Germany)

Biomedical devices and sensors often predominantly consist of a pure metal component or an alloyed metal. The surfaces of many biomedically relevant metals and alloys (e.g., Ti based) are covered with oxide layers. The latter are terminated with hydroxyl groups and consequently exhibit similar affinities to similar functional groups. Selective modification of different oxide substrates consequently is a challenging task, in contrast to noble metal – metal oxide composites where the difference in affinity to certain functional groups (e.g. thiols and silanes) can be exploited. The successful, selective self-assembled monolayer (SAM) formation on different metal oxides, however, could allow for an easy, substrate induced lateral structuring of the chemistry of designated positions in a device consisting of non-noble metals.

We designed a strategy to produce selectively modified mixed metal oxide surfaces and evaluated each step with XPS and ToF-SIMS. ZrO2 and TiO2 were chosen as a model system for the development of a general route to selectively assemble monolayers of functional molecules on metal oxide surfaces. Checkerboard patterns of the two oxides could be successfully modified with two different molecules in a four step procedure, in which initially both metal oxides are coated with a SAM of the first molecule, which is then selectively decomposed on the TiO2-areas and replaced with a second SAM after reactivation. Micro- to nanoscale structures were investigated.

11:40 AM Invited SI1-TuM-6 Surface Characterization of Oxide Passive Layers: From Chemistry to Applications in Corrosion and Biointerfaces
Anouk Galtayries (Institut de Recherche de Chimie Paris, CNRS-Chimie ParisTech, France)
Surface chemical analysis performed by techniques such as X-ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), which are Ultra-High Vacuum (UHV) techniques, is a powerful approach to characterize surface modifications of passive metals and/or oxidized surfaces in interaction with reactive aqueous liquids: it is applied in fields such as corrosion in liquid phase or biomaterials in biological solutions. In order to complete the investigation, one can combine UHV approach with real time in situ measurements: Quartz Crystal Microbalance (QCM) can allow useful complementary quantitative information and other aspects as regards kinetics of reactions. A selection of cases will be presented, emphasizing the multi-technique approach of identifying surface reactions occurring on well-characterized passive layers formed on alloys and metals: nickel-base alloys (containing Cr) exposed to high temperature, high pressure water, stainless steels exposed to naphtenic acids at high temperature, as well as metallic biomaterial exposed to solutions of biomolecules. Oxidation and/or adsorption mode, other surface mechanisms in the early stages of reactions on such metallic model systems can be determined from the combination of spectroscopic and gravimetric data and will be discussed in the context of more applied studies.
Time Period TuM Sessions | Abstract Timeline | Topic SI Sessions | Time Periods | Topics | SIMS2015 Schedule