Thermal melting of arachidic acid monolayers in ultrathin multilayers: A high-resolution x-ray diffraction study

Richardson, W.; Blasie, J. Kent

doi:10.1103/physrevb.39.12165

Cited by 18 publications

(8 citation statements)

References 20 publications

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“…There are only a few reports on the thermal stability of monolayers; here again data mostly pertain to alkanethiol systems. On the contrary, thermal behavior of Langmuir−Blodgett monolayers and multilayers have been investigated in detail . Infrared spectroscopy has been used to understand the phase stability of long-chain alkanethiol monolayers .…”

Section: Introductionmentioning

confidence: 99%

Self-assembled Monolayers of 1,4-Benzenedimethanethiol on Polycrystalline Silver and Gold Films: An Investigation of Structure, Stability, Dynamics, and Reactivity

1998

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1,4-Benzenedimethanethiol (HS−CH2−C6H4−CH2−SH, BDMT) adsorbs dissociatively on silver and gold surfaces yielding self-assembled monolayers with the thiolate structure. Whereas the molecule adsorbs flat on silver as a result of the loss of two thiol protons, it adsorbs with the molecular plane perpendicular to the gold surface with the loss of one thiol proton. This is manifested by the presence of the ring C−H and S−H stretches and the S−C−H bend for the Au monolayer and the absence of these for the Ag monolayer in the surface-enhanced Raman spectra. The difference in adsorbate geometry is presumably due to the changes in interaction and not to differences in the lattice constants of the two surfaces, which is rather small. In both cases, metal−adsorbate π bonding is weak, resulting in only small shifts in the ring modes. BDMT monolayers are more stable than alkanethiol monolayers and desorb only at a fairly high temperature of 423 K in air, whereas alkanethiols desorb below 373 K. An increase in temperature leads to structural changes in the Au monolayer and the molecules begin to lie flat on the surface, and desorption occurs from this state. The Ag monolayer is less stable thermally and desorption is eventless. Difference in the desorption temperatures point to the importance of energetics of self-assembly in determining the stability. The thiol proton on gold surfaces can be removed easily by exposing the monolayer to basic solutions. The gold monolayer upon exposure to thiols leads to the formation of disulfides, suggesting the formation of a prototypical bilayer. A completely new S−S stretching frequency is seen upon reaction with 4-methoxybenzenethiol (MOBT) with the complete absence of the S−H stretch. Other spectral features of the bilayer can be attributed to BDMT and MOBT subunits. The respective thiols in solution, however, do not react, leading to disulfide. Reaction with silver monolayer leads to the displacement of BDMT for MOBT and no reaction is observed. With n-alkanethiols, the reactivity decreases with the alkane chain length. The alkanethiol part of the spectrum resembles that of the corresponding self-assembled monolayer. Surface-enhanced reactivity of the type observed here has not been reported hitherto. The MOBT part of the bilayer desorbs first after cleaving the S−S bond and BDMT leaves the surface subsequently. X-ray exposure of the monolayers leads to beam-induced damage which is manifested in the Raman spectra. Whereas the damage is severe for Ag, part of the Au monolayer survives X-ray exposure.

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Section: Introductionmentioning

confidence: 99%

Self-assembled Monolayers of 1,4-Benzenedimethanethiol on Polycrystalline Silver and Gold Films: An Investigation of Structure, Stability, Dynamics, and Reactivity

1998

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“…The sum of energy-transfer rates from an arbitrary donor i to all acceptors is calculated by eq 12, where r¡;-is the distance *tí = (l/To)£(ro/ri;. )6 (12) ; between donor i and acceptor j. Figure 6 shows the schematic illustration of the numerical calculation.…”

Section: Resultsmentioning

confidence: 99%

Polymer Diffusion in a Layered Structure of Poly(vinyl pentanal acetal) Langmuir-Blodgett Films Studied by the Interlayer Energy-Transfer Method

Hayashi¹,

Okuyama²,

Ito³

et al. 1994

Macromolecules

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“…For samples containing BBC16, we used SAMs of a saturated C 18 hydrocarbon chain from the precursor octadecyltrichlorosilane (OTS). The procedure, based on that of Sagiv, has been used commonly in our group to prepare surfaces for LB deposition of fatty acid films. − Immediately following chemisorption of the SAMs, we characterized them by collecting about 12 h of X-ray interferometry data in a dry environment at room temperature.…”

Section: Methodsmentioning

confidence: 99%

“…The procedure, based on that of Sagiv, 14 has been used commonly in our group to prepare surfaces for LB deposition of fatty acid films. [15][16][17] Immediately following chemisorption of the SAMs, we characterized them by collecting about 12 h of X-ray interferometry data in a dry environment at room temperature.…”

Section: Introductionmentioning

confidence: 99%

X-ray Scattering Studies of Maquette Peptide Monolayers. 2. Interferometry at the Vapor/Solid Interface

et al. 2001

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We apply X-ray interferometry to study the profile structure of Langmuir-Blodgett (LB) monolayers containing maquette peptides, de novo di-R-helical synthetic peptides designed as model systems for studying biological electron transfer. The results demonstrate that it is possible to create monolayers with the peptide vectorially oriented with its helical axis (the direction of electron transfer within the holopeptide) approximately normal to the surface of the solid support. This orientation can even be achieved when the orientation of the peptide in the precursor Langmuir film at the air/water interface is parallel to the surface, indicating that reorganization of the monolayer can occur during or after LB deposition. Though issues regarding the low density of the film and variability between samples remain to be addressed, the work represents an important step toward future correlated functional/structural studies of these peptides.

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Thermal melting of arachidic acid monolayers in ultrathin multilayers: A high-resolution x-ray diffraction study

Cited by 18 publications

References 20 publications

Self-assembled Monolayers of 1,4-Benzenedimethanethiol on Polycrystalline Silver and Gold Films: An Investigation of Structure, Stability, Dynamics, and Reactivity

Self-assembled Monolayers of 1,4-Benzenedimethanethiol on Polycrystalline Silver and Gold Films: An Investigation of Structure, Stability, Dynamics, and Reactivity

Polymer Diffusion in a Layered Structure of Poly(vinyl pentanal acetal) Langmuir-Blodgett Films Studied by the Interlayer Energy-Transfer Method

X-ray Scattering Studies of Maquette Peptide Monolayers. 2. Interferometry at the Vapor/Solid Interface

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