Orientation and Electronic Structure of Ion-Exchanged Pyridinium Compounds on Mica

Zwahlen, Mathias; Brovelli, Dorothee; Caseri, Walter; Hähner, Georg

doi:10.1006/jcis.2002.8663

Cited by 10 publications

(16 citation statements)

References 24 publications

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“…These interactions may lead to an ion exchange between potassium atoms and cations of the IL, which in turn may lead to the mentioned island formation. 35 It is of great interest to compare our results with the studies of interfacial behavior of ILs by other research groups. Perkin et al studied the interfacial behavior of ILs confined between two mica surfaces using surface force apparatus.…”

Section: Resultsmentioning

confidence: 86%

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Interfacial Behavior of Thin Ionic Liquid Films on Mica

et al. 2013

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Ultrathin films of two imidazolium-based ionic liquids (ILs), [C1C1Im][Tf2N] (=1-methyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and [C4C1Im][Tf2N] (=1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) were deposited on mica surfaces by physical vapor deposition in ultrahigh vacuum. Using angle-resolved X-ray photoelectron spectroscopy (ARXPS), the initial wetting behavior, the growth characteristics, and the molecular arrangement of the ions at the interface were investigated. The measurements were performed on freshly air-cleaved mica surfaces with different carbon precoverages. ARXPS clearly reveals that the initial IL adsorption behavior strongly depends on the amount of preadsorbed carbon: On clean mica, 3D growth (complete dewetting) occurs, whereas on a fully carbon covered surface, initially a complete 2D wetting layer forms, followed by 3D growth.

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Section: Resultsmentioning

confidence: 86%

“…One other possibility could be that the IL species initially interact with potassium ions, which are located on top of the cleaved mica. These interactions may lead to an ion exchange between potassium atoms and cations of the IL, which in turn may lead to the mentioned island formation …”

Section: Resultsmentioning

confidence: 99%

Interfacial Behavior of Thin Ionic Liquid Films on Mica

et al. 2013

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“…33−35 This is attributed to the location of nitrogen atoms in an aromatic ring structure in DNA bases. 36,37 Similar to the nitrogen atom, the binding energy of P 2p for the cantilever modified by Apt1 and Apt2 in Figure 1D was about 133.4 eV, which is the characteristic peak of phosphate in the DNA backbone. 35 However, for the bare cantilever, no characteristic peak of nitrogen or phosphorus was observed.…”

Section: ■ Results and Discussionmentioning

confidence: 91%

“…Figure C shows the high-resolution XPS spectra of N 1s. On cantilevers modified by Apt1 and Apt2, there exhibited two characteristic peaks at about 399.0 and 400.5 eV, which are assigned to conjugated N (sp 2 ) and the mixture of amine group −NH 2 , nonconjugated N (sp 3 ), and N–(C)–N, respectively. − This is attributed to the location of nitrogen atoms in an aromatic ring structure in DNA bases. , Similar to the nitrogen atom, the binding energy of P 2p for the cantilever modified by Apt1 and Apt2 in Figure D was about 133.4 eV, which is the characteristic peak of phosphate in the DNA backbone . However, for the bare cantilever, no characteristic peak of nitrogen or phosphorus was observed.…”

Section: Results and Discussionmentioning

confidence: 97%

Microcantilever Array Biosensor for Simultaneous Detection of Carcinoembryonic Antigens and α-Fetoprotein Based on Real-Time Monitoring of the Profile of Cantilever

Guan

et al. 2019

ACS Sens.

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A microcantilever array biosensor based on a sandwich structure has been developed for simultaneously measuring two biomarkers carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) via an optical readout techniquereal-time monitoring of the profile of cantilever. First, the aptamers of CEA and AFP were self-assembled on their respective cantilevers. After the adsorption of the mixture of CEA and AFP, further specific interaction was performed via the addition of the antibodies specific to each target. The compressive stress on the cantilever was generated by the aptamer–antigen–antibody sandwich structure formed on the gold surface, resulting in cantilever bending. The profile of cantilever could be monitored in real time. The relationship between the deflection value at the 90% position of the cantilever and the target concentration served as a calibration curve, and the detection sensitivity was 1.3 ng/mL for CEA and 0.6 ng/mL for AFP, respectively. This work demonstrated the ability of simultaneously measuring two biomarkers via a microcantilever array biosensor, giving great potential for further application in detecting several targets simultaneously for early clinical diagnosis.

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“…The rather broad signal labeled 1 is due to second-order intensity from oxygen of the mica [20]. The small peak labeled 2 at 285 eV is due to carbon inclusions in the mica substrate [30]. The signal labeled 3 is related to transitions into C-H orbitals of the alkyl chains, feature 4 is indicative of the C-C bond, and 5 is the signal from the potassium 2p [20].…”

Section: Solvent Dependencementioning

confidence: 96%