Selectivity self-assembled” monolayers

Figure Bl.22.3. RAIRS data in the C-H stretching region from two different self-assembled monolayers, namely, from a monolayer of dioctadecyldisulfide (ODS) on gold (bottom), and from a monolayer of octadecyltrichlorosilane (OTS) on silicon (top). Although the RAIRS surface selection rules for non-metallic substrates are more complex than those which apply to metals, they can still be used to detemiine adsorption geometries. The spectra shown here were, in fact, analysed to yield the tilt (a) and twist (p) angles of the molecular chains in each case with respect to the surface plane (the resulting values are also given in the figure) [40].

Sequence-specific biosensor, 183, 185 Selectivity, 92, 143, 147, 155 Selectivity coefficient, 143 Self-assembled monolayers, 39, 118 Selenium, 85 Sensor, 171 Silver halide, 159 Simulation, 35... 

Self-assembled monolayers (SAMs) [8] The layers are formed by heterologous interaction between reactive groups, such as thiols, and noble metals, such as gold or silver. Since the molecules are selectively adsorbed on these metals, film growth stops after the first monolayer is completed. The molecular aggregation is enthalpy driven, and the final structure is in thermodynamic equilibrium. 

Coupling of affinity molecules to surfaces also can be enhanced by the use of discrete PEG linkers. Nishimura et al. (2005) modified an amino surface with a NHS-PEG -maleimide crosslinker to create a hydrophilic self-assembled monolayer (SAM) surface that was thiol reactive for the conjugation of sulfhydryl-modified RNAs. This array then was used to investigate the binding specificity of synthetic kanamycins with selected RNA sequences to prove the specific interaction of ribosomal RNA with this molecule. The PEG linkers on surfaces provide lower nonspecific binding character than alkyl linkers, when preparing SAM surfaces for affinity interactions. 

Kidambi, S., Chan, C., and Lee, I. (2004) Selective depositions on polyelectrolyte multilayers Self-assembled monolayers of m-dPEG acid as molecular template./. Am. Chem. Soc. 126, 4697-4703. 

Ray SG, Daube SS, Leitus G, Vager Z, Naaman R (2006) Chirality-induced spin-selective properties of self-assembled monolayers of DNA on gold. Phys Rev Lett 96(3) 036101... 

Hou et al. developed a method that controlled the generation of a nanomolar amount of NO [173]. A self-assembled monolayer of N-nitroso-N-oxy-p-thiomethyl-benzeamine ammonium salt bound to a gold electrode via a thiol linkage was used for the reaction. When an electric potential was applied, one-electron electrochemical oxidation led to the release of NO (Scheme 3.20). There was a linear relationship between the amount of NO generated and the area of the electrode, indicating that the amount of NO release could be controlled by selecting an appropriately sized... 

Nealey and coworkers [75,76,146] took a similar approach and applied lithographically defined self-assembled monolayers as substrates to direct the orientation of block copolymer thin films. After EUV interferometic lithography on octadecyltrichlorosilane (OTS) or phenylethyltrichlorosilane (PETS) monolayers, PS-fr-PMMA block copolymers were deposited and annealed on the substrates. Due to the selective wetting of PS and PMMA on the unexposed and exposed regions, respectively, they were able to obtain large areas of perpendicular lamella when the commensurate condition was fulfilled. 

Callow ME, Callow JA, Ista LK, Coleman SE, Nolasco AC, Lopez GP (2000) Use of self-assembled monolayers of different wettabilities to study surface selection and primary adhesion processes of green algal (Enteromorpha) zoospores. Appl Environ Microbiol 66 3249-3254... 

Fig. 9.1 A schematic illustration of surface coatings with their typical thickness ranging from angstroms to micrometers. Selected are monomolecular layers fabricated by the transfer of Langmuir-Blodgett (LB) films onto solid substrates (1) self-assembled monolayers (SAMs) (2) multilayers thereof (3) polymer-...

Zhou C, Nagy G, Walker AV (2005) Toward molecular electronic circuitry selective deposition of metals on patterned self-assembled monolayer surfaces. J Am Chem Soc 127 12160-12161... 

Park MH, Jang YJ, Sung-Suh HM, Sung MM (2004) Selective atomic layer deposition of titanium oxide on patterned self-assembled monolayers formed by microcontact printing. Langmuir 20 2257-2260... 

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