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We present an ARXPS study on the surface composition and interfacial behavior of commercial [Rh(COD)2][TfO] in [C2C1Im][TfO], [C4C1Im][TfO], [C8C1Im][TfO], and [C2C1Im][EtOSO3]. The complex was found to be non-intact in a solution of these ILs through the loss of COD ligands, accompanied by the depletion of the metal center from the IL/vacuum interface. Increasing the chain length of the aliphatic substituent on the imidazolium cation of the [TfO]−-based ILs led to a more pronounced depletion from the interface, due to the higher surface affinity of the solvent cations with the longer alkyl chains. The loss of COD ligands offered facile in situ ligand substitution with surface-active TPPTS to afford a moderate increase in the surface concentration of Rh. We propose the formation of a Schrock−Osborn-type catalyst [Rh(COD)(TPPTS)2][TfO]. Information on the surface composition and targeted design of the gas/IL interface is highly relevant for applications in IL-based catalytic systems, such as in supported ionic liquid phase (SILP) catalysis.

We studied the adsorption and reaction behavior of the ionic liquid (IL) 1,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C1C1Im][Tf2N]) on Cu(111) using non-contact atomic force microscopy (nc-AFM), scanning tunneling microscopy (STM), and angle-resolved X-ray photoelectron spectroscopy (ARXPS) in ultrahigh vacuum as a function of temperature, supported by density-functional theory (DFT) calculations. Our nc-AFM results for sub-monolayer IL films show that at 200 K, the IL self-assembles into highly ordered islands, with cations and anions arranged next to each other in a checkerboard–type phase. After extended annealing at 300 K, the structure transforms first to a hexagonal phase and then to a porous honeycomb phase. Simultaneously, many small, disordered islands are formed. Complementary ARXPS reveals no IL desorption until 300 K. However, a significant fraction of the IL is converted to a new species as deduced from new, strongly shifted peaks that develop in the XP spectra at around 275 K and grow with annealing time at 300 K. We correlate the remaining unshifted peaks to the ordered phases observed in nc-AFM and the shifted peaks to decomposition products, which appear as disordered islands in nc-AFM and STM. Upon further heating to 360 K, about 50% of the anions or their decomposition products desorb from the surface, while cation-related fragments mostly remain on the surface. From DFT, we obtain additional information on the structure of the ordered phases and the interaction of the IL with the substrate.

Background: Although many countries have introduced strict guidelines regarding mouth and nose coverage in public to contain infection rates during the SARS-CoV-2 pandemic, more information is needed regarding the impact of wearing face masks on lactate thresholds (LT) and performance parameters during exercise. Methods: Ten healthy male and 10 healthy female subjects (age = 33.4 [10.26] y, body mass index = 23.52 [2.36] kg/m2) performed 3 incremental performance tests, wearing no mask (NM), surgical mask (SM), and filtering face piece mask class 2 (FFP2), with a cycle ergometer. The authors analyzed changes in the LT, in blood gas parameters, and in the rating of perceived exertion (RPE). Results: Performance at LT remained unchanged in subjects wearing SM or FFP2 in comparison with NM (162.5 [50.6] vs 167.2 [58.9] vs 162.2 [58.4] W with NM, SM, and FFP2, respectively, P = .24). However, the peak performance was significantly reduced wearing FFP2 compared with NM (213.8 [71.3] vs 230.5 [77.27] W, FFP2 vs NM, respectively, P P P P Conclusion: Wearing face masks during exercise showed no effect on LT, limited maximum performance, and induced discrete changes in capillary pCO2 and pO2 within the physiologic range while increasing RPE at LT.

The targeted enrichment of a Pt complex with an ionic liquid (IL)‐derived ligand system in IL solution is demonstrated by using angle‐resolved X‐ray photoelectron spectroscopy. When the ligand system is complemented with fluorinated side chains, the complex accumulates strongly at the IL/gas interface, while in an equivalent solution of a complex without these substituents no such effect could be observed. This buoy‐like behavior induces strong population of the complex at the outermost molecular layer close to surface saturation, which was studied over a range from 5 to 30 %mol. The surface enrichment was found to be most efficient at the lowest concentration, which is particularly favorable for catalytic applications such as supported ionic‐liquid‐phase (SILP) catalysis.

We report on the surface and interface tension measurements of the two ionic liquids (ILs) [C8C1Im][PF6] and [m(PEGn)2Im]I (n = 2, 4, 6) in a surface science approach. The measurements were performed in a newly developed and unique experimental setup, which allows for surface tension (ST) measurements using the pendant drop method and for contact angle measurements using the sessile drop method under the well-defined conditions of a high vacuum (from 10−7 mbar). The setup also allows for in vacuum transfer to an ultrahigh vacuum system for surface preparation and analysis, such as in angle-resolved X-ray photoelectron spectroscopy. For [C8C1Im][PF6], we observe a linear decrease in the surface tension with increasing temperature. The ST measured under high vacuum is consistently found to be larger than under ambient conditions, which is attributed to the influence of water uptake in air by the IL. For [m(PEGn)2Im]I (n = 2, 4, 6), we observe a decrease in the ST with increasing polyethylene glycol chain length in a vacuum, similar to very recent observations under 1 bar Argon. This decrease is attributed to an increasing enrichment of the PEG chains at the surface. The ST data obtained under these ultraclean conditions are essential for a fundamental understanding of the relevant parameters determining ST on the microscopic level and can serve as a benchmark for theoretical calculations, such as molecular dynamic simulations. In addition to the ST measurements, proof-of-principle data are presented for sessile drop measurements in HV, and a detailed description and characterization of the new setup is provided.

We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile‐functionalized ionic liquids (ILs) in solution using angle‐resolved X‐ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by simple ligand substitution under vacuum conditions in defined excess of the coordinating ILs, [C3CNC1Im][Tf2N] and [C1CNC1Pip][Tf2N], to immediately yield solutions of the final products. The ILs differ in the cationic head group and the chain length of the functionalized substituent. Our XPS measurements on the neat ILs gave insights in the electronic properties of the coordinating substituents revealing differences in donation capability and stability of the complexes. Investigations on the composition of the outermost surface layers using ARXPS revealed no surface affinity of the nitrile‐functionalized chains in the neat ILs. Solutions of the formed complexes in the nitrile ILs showed homogeneous distribution of the solute at the surface with the heterocyclic moieties preferentially orientated towards the vacuum, while the metal centers are rather located further away from the IL/vacuum interface.

We have studied the adsorption, wetting, growth, and thermal evolution of the protic IL diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) on Au(111) and Ag(111). Ultrathin films were deposited at room temperature (RT) and at 90 K, and were characterized in situ by angle-resolved X-ray photoelectron spectroscopy. For both surfaces, we observe that independent of temperature, initially, a closed 2D wetting layer forms. While the film thickness does not increase past this wetting layer at RT, at 200 K and below, "moderate" 3D island growth occurs on top of the wetting layer. Upon heating, on Au(111), the [dema][TfO] multilayers desorb at 292 K, leaving an intact [dema][TfO] wetting layer, which desorbs intact at 348 K. The behavior on Ag(111) is much more complex. Upon heating [dema][TfO] deposited at 90 K, the [dema]+ cations deprotonate in two steps at 185 and 305 K, yielding H[TfO] and volatile [dema]0. At 355 K, the formed H[TfO] wetting layer partly desorbs (∼50%) and partly decomposes to form an F-containing surface species, which is stable up to 570 K.

How do board characteristics influence the risk of bankruptcy? We study this question by estimating classic Z-Score models using panel data comprising 2519 listed non-financial firms from 29 European countries over the 2012–2020 period. We found that board independence is associated with lower risk of bankruptcy. In contrast, employee representatives have an adverse effect on board monitoring capacity and are predicted to increase bankruptcy risk. The presence of female directors and foreign directors on board—two indicators of board diversity—reduce bankruptcy risk. While board independence and diversity decrease bankruptcy risk in financially non-distressed firms, they have the opposite effect in financially distressed firms. These findings are statistically and economically significant and hold, at least in part, under alternative specifications. Our findings demonstrate the need for governance regulators, credit rating agencies, financial institutions, firms and investors to lend more weight to board composition, especially under the conditions of impending financial distress.

We investigated the adsorption, surface enrichment, ion exchange, and on‐surface metathesis of ultrathin mixed IL films on Ag(111). We stepwise deposited 0.5 ML of the protic IL diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) and 1.0 ML of the aprotic IL 1‐methyl‐3‐octylimidazolium hexafluorophosphate ([C8C1Im][PF6]) at around 90 K. Thereafter, the resulting layered frozen film was heated to 550 K, and the thermally induced phenomena were monitored in situ by angle‐resolved X‐ray photoelectron spectroscopy. Between 135 and 200 K, [TfO]− anions at the Ag(111) surface are exchanged by [PF6]− anions and enriched together with [C8C1Im]+ cations at the IL/vacuum interface. Upon further heating, [dema][PF6] and [OMIm][PF6] desorb selectively at ∼235 and ∼380 K, respectively. Hereby, a wetting layer of pure [C8C1Im][TfO] is formed by on‐surface metathesis at the IL/metal interface, which completely desorbs at ∼480 K. For comparison, ion enrichment at the vacuum/IL interface was also studied in macroscopic IL mixtures, where no influence of the solid support is expected.

Hamm, Wolfgang, Sari Kassem, Lukas von Stülpnagel, Florian Maier, Mathias Klemm, Dominik Schüttler, Felix Grabher, Ludwig T. Weckbach, Bruno C. Huber, Axel Bauer, Konstantinos D. Rizas, and Stefan Brunner. Deceleration capacity and periodic repolarization dynamics as predictors of acute mountain sickness.

Das Auftreffen eines Reaktanten aus der Gasphase auf die Oberfläche einer Flüssigkeit und dessen Transfer durch die Gas/Flüssig‐Grenzfläche sind äußerst wichtig für verschiedene Konzepte in der Katalyse, bei denen ionische Flüssigkeiten (engl. ionic liquids, ILs) verwendet werden. Wir haben daher die Adsorptionsdynamik von n‐Butan auf einer Reihe von 1‐Alkyl‐3‐methyl‐imidazolium‐bis(trifluoromethansulfonyl)imid‐ILs ([CnC1Im][Tf2N]; n=1, 2, 3, 8) mithilfe eines Überschallmolekularstrahls im Ultrahochvakuum auf gefrorenen IL‐Oberflächen in Abhängigkeit der Oberflächentemperatur zwischen 90 und 125 K bestimmt. Auf den C8‐ und C3‐ILs adsorbiert n‐Butan bei 90 K mit einem Anfangshaftfaktor von ≈0.89. Die Adsorptionsenergie steigt mit zunehmender Länge der Alkylseitenkette im Kation, während die ionischen Kopfgruppen anscheinend nur schwach mit n‐Butan wechselwirken. Im Gegensatz dazu findet auf den C1‐ und C2‐ILs keine Adsorption statt. Dies führen wir auf eine zu kurze Verweilzeit auf der IL‐Oberfläche zurück, weshalb selbst bei 90 K keine Kondensationskeime gebildet werden können.

Mixtures of fluorinated and non-fluorinated ionic liquids (ILs) show a distinct structural organization in the bulk and at the surface. To understand how such microscopic effects influence the macroscopic bulk and surface properties of IL mixtures, knowledge of corresponding thermophysical properties including viscosity and surface tension is required yet lacking. With the intention of investigating surface enrichment effects of the fluorinated IL [PFBMIm][PF6] (3-methyl-1-(3,3,4,4,4-pentafluorobutyl)imidazolium hexafluorophosphate) in mixtures with the structurally similar, non-fluorinated IL [C4C1Im][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) observed with angle-resolved X-ray photoelectron spectroscopy (ARXPS), the pendant drop method and surface light scattering (SLS) were applied in the present study to determine surface tension and dynamic viscosity between (293 and 368) K. By adding small amounts of [PFBMIm][PF6] up to 9 mol %, a distinct increase in the viscosity and decrease in the surface tension of the mixtures relative to the properties of pure [C4C1Im][PF6] was found. This behavior reflects the nanosegregated structure in the bulk and at the surface of the binary IL mixtures. Using the results about the pronounced surface enrichment of the fluorinated chain of [PFBMIm][PF6] quantified by ARXPS, a linear mixing rule for the surface tension of the IL mixtures based on the surface tensions of the pure ILs and the surface concentration of their most surface-active groups is suggested.

The migration of Manufacturing Execution Systems could eliminate existing paper-based communication media for engineers and operators. This paper presents an approach to solve the resulting information deficit for the R&D process by the integration of a digital operator support system in a human-centered production environment. The design of the solution is based on analyzing the problem statement from two perspectives: (1) Logistics and material flow, (2) applied computer science. For (1) the machine setup is analyzed leveraging the Single Minute Exchange of Dies method. For (2) the design of the user interface for the digital operator support system the standards DIN EN ISO 9241-110 and DIN EN ISO 9241-12 are applied. The solution has been applied and evaluated through a user survey and measuring production performance indicators. Analysis of collected data shows increased user satisfaction and increased worker confidence of over 90% and a reduction of re-work up to 80%.

Ionic liquids (ILs) are used as ultrathin films in many applications. We studied the nanoscale arrangement within the first layer of 1,3-dimethylimidazo­lium bis[(trifluoro­methyl)­sulfonyl]imide ([C1C1Im][Tf2N]) on Au(111) between 400 and 110K in ultra-high vacuum by scanning tunneling and non-contact atomic force microscopy with molecular resolution. Compared to earlier studies on similar ILs, a different behavior is observed, which we attribute to the small size and symmetrical shape of the cation: (a) In both AFM and STM only the anions are imaged; (b) only long-range-ordered but no amorphous phases are observed; (c) the hexagonal room-temperature phase melts 30-50 K above the IL’s bulk melting point; (d) at 110 K, striped and hexagonal superstructures with two and three ion pairs per unit cell, respectively, are found. AFM turned out to be more stable at higher temperature, while STM revealed more details at low temperature.

Reactions of copper, silver, and gold with the imidazolium-based polyhalide ionic liquid (IL) [C6C1Im][Br2I] are investigated by X-ray photoelectron spectroscopy (XPS), weight loss measurements and gas phase mass spectrometry. All three group 11 metals are strongly corroded by the IL at moderate temperatures, yielding a very high content of dissolved Cu(I), Ag(I), and Au(I) species. The IL-metal solutions are stable against contact with water and air. Replacing imidazolium by inorganic sodium cations decreases metal corrosion rates by orders of magnitude. Our results clearly indicate metal oxidation by iodide from dibromo­iodide anions forming molecular iodine and anionic [Br-M(I)-Br]- (M = Cu, Ag, Au) complexes stabilised by imidazolium counter-cations. From experiments with a trihalide IL with imidazolium methylated in 2-position we rule out imidazole-carbene formation being responsible for the observed corrosion. In contrast to the group 11 metals, molybdenum is inert against the trihalide IL, which is attributed to surface passivation.

The capability for contact formation on indium tin oxide layers of different low-temperature screen printing silver pastes after thermal curing and photonic sintering is evaluated in detail. The 80-nm-thick indium tin oxide layers used in this study are sputtered at three different oxygen gas flows and, consequently, differ by their electrical and optical properties. All pastes are analyzed by means of simultaneous thermogravimetry-differential scanning calorimetry. After printing and contact formation processing, the lateral resistivity of the metal contacts and their contact resistivity to the indium tin oxide layers are determined. Furthermore, the microstructure of the metal electrodes is investigated to gain a deeper understanding of the underlying contact formation mechanisms. Besides low-temperature curing at T curing, low = 180–220 °C, as conventionally applied to silicon heterojunction solar cells, photonic sintering and thermal curing at medium temperatures T curing, mid = 250–350 °C are utilized. The higher curing temperatures in the range of T curing, mid enhance the sintering and densification processes of the different pastes, and thereby, lateral resistivities of 2.4–3.5 μΩ⋅cm and contact resistivities of 1.0–2.5 mΩ⋅cm2 are achieved. The results indicate a promising industry-relevant non-firing-through metallization approach for, e.g., poly-silicon-based structures like tunnel oxide passivating contacts, which allow comparatively high temperatures for contact formation processing. With thermal curing at T curing, low and photonic sintering, both compatible with temperature-sensitive silicon heterojunction solar cells, lateral finger resistivities of 6.5–9.4 μΩ⋅cm and contact resistivities of 1.2–2.5 mΩ⋅cm2 are achieved. Thereby, photonic sintering has the potential of a significantly reduced process time from several minutes down to 1–4 ms.

At 298 K, the surface tension of ionic liquids ( ILs ) of the 1-alkyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide series, [CnC1Im][NTf2], ranges from around 35 mN·m−1 for [C2C1Im][NTf2] to just below 30 mN·m−1 for [C12C1Im][NTf2]. However, the decrease rate along the series is not constant: a large decrease from [C2C1Im][NTf2] to [C8C1Im][NTf2] is followed by almost constant values from [C8C1Im][NTf2] to [C12C1Im][NTf2]. Such behavior is hard to interpret from a molecular point of view without suitable information about the free-surface structure of the different ILs. In this work, we have successfully used the Langmuir principle in combination with structural data obtained from angle-resolved X-ray photoelectron spectroscopy experiments and molecular dynamics simulations, to predict the correct surface tension trend along the IL series. The concepts unveiled for this particular homologous IL family can be easily extended to other systems.