Molecular self-assembled monolayer

DiBenedetto SA, Facchetti A, Ratner MA, Marks TJ (2009) Molecular self-assembled monolayers and multilayers for organic and unconventional inorganic thin-film transistor applications. Adv Mater 21 1407-1433... 

W. Wang, T. Lee, and M. A. Reed, Electronic transport in molecular self-assembled monolayer devices, Proc. IEEE, 93, 1815, 2005. 

Salmeron M, Liu G-Y and Ogletree D F 1995 Molecular arrangement and mechanical stability of self-assembled monolayers on Au(111) under applied load Force in Scanning Probe Methods ed H-J Guntherodt et al (Amsterdam Kluwer)... 

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].

Self-assembled monolayers (SAMs) are molecular layers tliat fonn spontaneously upon adsorjDtion by immersing a substrate into a dilute solution of tire surface-active material in an organic solvent [115]. This is probably tire most comprehensive definition and includes compounds tliat adsorb spontaneously but are neither specifically bonded to tire substrate nor have intennolecular interactions which force tire molecules to organize tliemselves in tire sense tliat a defined orientation is adopted. Some polymers, for example, belong to tliis class. They might be attached to tire substrate via weak van der Waals interactions only. 

Harder P, Grunze M, Dahint R, Whitesides G M and Laibinis P E 1998 Molecular conformation in oligo(ethylene glycol)-terminated self-assembled monolayers on gold and silver surfaces determines their ability to resist protein adsorption J. Rhys. Chem. B 102 426-36... 

Fig. 28. Self-assembly monolayer to function as molecular recognition iaterface (182).

Israelachvili and coworkers [64,69], Tirrell and coworkers [61-63,70], and other researchers employed the SFA to measure molecular level adhesion and deformation of self-assembled monolayers and polymers. The pull-off force (FJ, and the contact radius (a versus P) are measured. The contact radius, the local radius of curvature, and the distance between the surfaces are measured using the optical interferometer in the SFA. The primary advantage of using the SFA is its ability to study the interfacial adhesion between thin films of relatively high... 

As reviewed so far, the contact-mechanics-based techniques (JKR and SFA methods) have been effective in the understanding molecular level mechanisms related to the adhesion of elastomers and in measuring the surface and interfacial energies of polymers and self-assembled monolayers. The current work in this area is aimed at understanding contact induced interfacial rearrangements and the role of specific interactions. The recent progress of these studies is discussed in this section. 

Hu, Y. Z., Zhang, T., and Wang, H., "Molecular Dynamics Simulations on Atomic Friction Between Self-Assembled Monolayers Commensurate and Incommensurate Sliding," Comp. Mater. Sci., Vol. 38,2006, pp. 98-104. 

The importance of surface characterization in molecular architecture chemistry and engineering is obvious. Solid surfaces are becoming essential building blocks for constructing molecular architectures, as demonstrated in self-assembled monolayer formation [6] and alternate layer-by-layer adsorption [7]. Surface-induced structuring of liqnids is also well-known [8,9], which has implications for micro- and nano-technologies (i.e., liqnid crystal displays and micromachines). The virtue of the force measurement has been demonstrated, for example, in our report on novel molecular architectures (alcohol clusters) at solid-liquid interfaces [10]. 

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. 

When appropriate molecular-molecular and molecular-surface interactions are present, an ordered monolayer is formed spontaneously on surfaces (Figure 16.1). This process is called self-assembly (SA) and monolayers formed in this manner are called self-assembled monolayers (SAMs). 

Lagutchev A, Patterson JE, Huang W, Dlott DD. 2005. Ultrafast dynamics of self-assembled monolayers under shock compression Effects of molecular and substrate structiue. J Phys ChemB 109 5033-5044. 

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. 

As the analytical, synthetic, and physical characterization techniques of the chemical sciences have advanced, the scale of material control moves to smaller sizes. Nanoscience is the examination of objects—particles, liquid droplets, crystals, fibers—with sizes that are larger than molecules but smaller than structures commonly prepared by photolithographic microfabrication. The definition of nanomaterials is neither sharp nor easy, nor need it be. Single molecules can be considered components of nanosystems (and are considered as such in fields such as molecular electronics and molecular motors). So can objects that have dimensions of >100 nm, even though such objects can be fabricated—albeit with substantial technical difficulty—by photolithography. We will define (somewhat arbitrarily) nanoscience as the study of the preparation, characterization, and use of substances having dimensions in the range of 1 to 100 nm. Many types of chemical systems, such as self-assembled monolayers (with only one dimension small) or carbon nanotubes (buckytubes) (with two dimensions small), are considered nanosystems. 

Selzer Y, Cai L, Cabassi MA, Yao Y, Tour JM, Mayer TS, Allara DL (2004) Effect of local environment on molecular conduction isolated molecule versus self-assembled monolayer. 

Burtman V, Ndobe AS, Vardeny ZV (2005) Transport studies of isolated molecular wires in self-assembled monolayer devices. J Appl Phys 98(3) 034314-034319... 

Ashwell GJ, Tyrrell WD, Whittam AJ (2005) Molecular rectification self-assembled monolayers in which donor-(7i-bridge)-acceptor moieties are centrally located and symmetrically coupled to both gold electrodes. J Am Chem Soc 126 7102-7110... 

Chabinyc ML, Chen X, Holmlin RE, Jacobs H, Skulason H, Frisbie CD, Mujica V, Ratner MA, Rampi MA, Whitesides GM (2002) Molecular rectification in a metal-insulator-metal junction based on self-assembled monolayers. J Am Chem Soc 124 11731-11736... 

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