Self-assembled monolayers chemistry

Combining this self-assembled monolayer chemistry with AFM tip apparatus yields a new AFM-based soft lithography technique, which is often called dip-pen nanohthography (Fig. 4.42). It can be used to write very line patterns on metal and semiconductor surfaces using a solution of monolayer-forming materials as ink. 

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]. 

Ford, M.J., Hoft, R.C. and McDonagh, A. (2005) Theoretical study of ethynylbenzene adsorption on Au(lll) and implications for a new class of self-assembled monolayer. The Journal of Physical Chemistry. B, 109, 20387-20392. 

As this volume attests, a wide range of chemistry occurs at interfacial boundaries. Examples range from biological and medicinal interfacial problems, such as the chemistry of anesthesia, to solar energy conversion and electrode processes in batteries, to industrial-scale separations of metal ores across interfaces, to investigations into self-assembled monolayers and Langmuir-Blodgett films for nanoelectronics and nonlinear optical materials. These problems are based not only on structure and composition of the interface but also on kinetic processes that occur at interfaces. As such, there is considerable motivation to explore chemical dynamics at interfaces. 

Cornelius RM, Shankar SP, Brash JL, Babensee JE (2011) Immunoblot analysis of proteins associated with self-assembled monolayer surfaces of defined chemistries. J Biomed Mater Res 98A 7-18... 

Similar SCS-Pd(II) complexes have also been used to prepare isolated nanometer-sized objects within a decanethiol self assembled monolayer on gold [88]. In this chemistry, the thioether derivative of a pyridine complex of the SCS-Pd(ll) complex 22 was first prepared and immobilized on gold as part of a self assembled monolayer. Then the much better phosphine ligand... 

Flowever, the focus of the major part of the chapters lies on the couphng chemistry used for DNA immobilization. Successful immobihzation techniques for DNA appear to either involve a multi-site attachment of DNA (preferentially by electrochemical and/or physical adsorption) or a single-point attachment of DNA (mainly by surface activation and covalent immobihzation or (strept)avidin-biotin linkage). Immobilization methods described here comprise physical or electrochemical adsorption, cross-linking or entrapment in polymeric films, (strept)avidin-biotin complexation, a surface activation via self-assembled monolayers using thiol linker chemistry or silanization procedures, and finally covalent coupling strategies. 

Finklea, H.O. Self-assembled monolayers on Electrodes. In Encyclopedia of Analytical Chemistry Applications, Theory and Instrumentations, Meyers, R.A. Ed. John Wiley Sons Chichester, 2000 Vol. 11, pp.10090-101000... 

Raton (Ed. K. S. Birdi) Self-Assembly Monolayer (Plenum Press, New York, 1999) and Scanning Probe Microscopes (CRC, Boca Raton, 2002a). Surface and colloid chemistry has remained his major interest of research. 

Zhu Z, Allara DL, Winograd N (2006) Chemistry of metal atoms reacting with alkanethiol self-assembled monolayers. Appl Surf Sci 252(19) 6686-6688... 

One of the points made in Schwenz and Moore was that the physical chemistry laboratory should better reflect the range of activities found in current physical chemistry research. This is reflected in part by the inclusion of modem instrumentation and computational methods, as noted extensively above, but also by the choice of topics. A number of experiments developed since Schwenz and Moore reflect these current topics. Some are devoted to modem materials, an extremely active research area, that I have broadly construed to include semiconductors, nanoparticles, self-assembled monolayers and other supramolecular systems, liquid crystals, and polymers. Others are devoted to physical chemistry of biological systems. I should point out here, that with rare exceptions, I have not included experiments for the biophysical chemistry laboratory in this latter category, primarily because the topics of many of these experiments fall out of the range of a typical physical chemistry laboratory or lecture syllabus. Systems of environmental interest were well represented as well. 

In addition to Grignard chemistry and hydrogermylation, for which analogs also exist for silicon, there is another type of functionalization chemistry that has been carried out on germanium surfaces that of alkanethiol attachment to H-terminated Ge. Alkanethiols are well known for their use in self-assembled monolayers (SAMs) on gold surfaces. 

Like the currently popular area, called nanoscience , the field of supramolecular chemistry has rather hazy boundaries. Indeed, both areas now share much common ground in terms of the types of systems that are considered. From the beginning, electrochemistry, which provides a powerful complement to spectroscopic techniques, has played an important role in characterizing such systems and this very useful book goes considerably beyond the volume on this same topic by Kaifer and Gomez-Kaifer that was published about 10 years ago. Some of the classic supramolecular chemistry topics such as rotaxanes, catenanes, host-guest interactions, dendrimers, and self-assembled monolayers remain, but now with important extensions into the realms of fullerenes, carbon nanotubes, and biomolecules, like DNA. 

Instead of considering wettability from the above traditional perspective, let us look at it from the opposite side What if we can control wettability of a surface at microscopic length scales, perhaps actively New developments in surface chemistry and fabrication of self-assembled monolayers (SAMs see Chapter 7) have opened up precisely such a possibility. How can we take advantage of such opportunities ... 

FIG. 6.1 Control of wettability of surfaces through chemistry (a) schematic illustration of formation of hydrophobic lines on a hydrophilic surface with self-assembled monolayers (SAMs) and micromachining (b) top view of the shapes and confinement of water drops on an engineered surface. (Reproduced with permission of Abbott et al. 1992.)... 

Figure 6.12 The molecular capsule 6.33b-6.34 held by interactions to cyclodextrins as a self-assembled monolayer on gold. (Reproduced by permission of The Royal Society of Chemistry).

---