Surface self-assembly

Most studies of ORR catalysis by metalloporphyrins have been carried out using water-insoluble catalysts absorbed on a graphite electrode in contact with aqueous solution. In a limited number of cases, four other approaches have been used catalysts imbedded in an inert film (i.e., Nafion or lipid) on the electrode surface self-assembled monolayers of catalysts catalysts in aqueous or mixed organic/aqueous solutions in contact with an electrode and catalysis in mixed aqueous/organic medium using... 

Gold-Coated Surfaces Self-Assembled Monolayers of Thiols. 91... 

Lepeie M, Chevallard C, Hernandez J-F, Mitraki A, Guenoun P. Multiscale surface self-assembly of an amyloid-like peptide. Langmuir 2007 23 8150-8155. 

Keywords wrinkling Thin-film Elastomeric polymer Polydimethylsiloxane Patterns Deformation Surfaces Self-assembly Polyelectrolyte multilayer films Thin-films Polymer brushes Colloidal crystallization Mechanical-properties Assembled monolayers Buckling instability Elastomeric polymer Tobacco-mosaic-virus Soft lithography Arrays... 

Important techniques for bottom-up nanofabrication include soft lithography and surface self-assembly. Also the use of containers such as carbon nanotubes to confine molecular scale objects in one dimension is a useful tool. 

Along with monolayers on surfaces, self-assembled liquid crystals are of interest and a range of bispyridines and the tetracarboxylic acid 65 have been examined. The dynamic nature of the hydrogen-bond networks produced allows a range of phases to be realized <1996CM961>. 

Finally, we mention a remarkable example of lateral resolution reported for supramolecular nanostructures on hopg [96]. Held together by 72 hydrogen bonds, the molecular nanostructure is formed from three melamine-substituted calix[4]arene units and twelve 5,5-diethylbarbiturate molecules (Fig. 31a). The nanostructure, basically a stack of four rosettes, has chiral symmetry. With its components all being achiral, both enantiomers are formed upon self-assembly in solution. Deposition of the tetrarosettes on hopg leaves this nanostructure intact and allows surface self-assembly. AFM studies revealed close-packed 2D lattices formed by the tetrarosettes on hopg... 

Surface self-assembly. On the basis of an amphiphilic adsorption strategy, instead of chemical immobilization, non-covalent supermolecular systems can be constructed by SMA surface self-assembly. The represen-... 

Whitesides, G. M., and Laibinis, P. E. Wet chemical approaches to the characterization of organic surfaces self-assembled monolayers, wetting, and the physical-organic chemistry of the solid-liquid interface. Langmuir, 6, 87 (1990). 

Langmuir monolayers were reported by Mohwald and co-workers in 1986 1. Since then, scattering of X-rays has been successfully applied to elucidate the structure of condensed phases of monolayers at the water surface, self-assembled mono-layers and LB films. In addition, it has become possible to monitor by diffraction the growth and dissolution of 2D crystalline aggregates as well as structural changes in monolayers incurred upon phase transitions. There are several overviews of what has been achieved 2). 

Delamarche, B. Michel, H.A. Biebuyck, and C. Gerber, Golden interfaces the surface self assembled monolayers, Adv. Mater. 8, 719 729 (1996). 

Yi, X., Pavlov, V., Gill, R., Bourenko, T., Willner, I. (2004). Lighting up biochemiluminescence by the surface self-assembly of DNA-hemin complexes. Chembiochem 5, 374-379. 

Jia, Y., Liu, X., 2006. From surface self-assembly to crystallization prediction of protein crystallization conditions. J. Phys. Chem. B 110, 6949—6955. 

Munoz-Bonilla, A., Ibarboure, E., Papon, E., Rodriguez-Hemandez, J. Self-organized hierarchical structures in polymer surfaces self-assembled nanostructures within breath figiues. Langmuir 25, 6493-6499 (2009)... 

In this section, we do not examine the formation of linear structures in which the bnilding block/surface interaction assembles molecular species that would not otherwise interact in solution. A wealth of interactions and surface specific effects are known to affect the assembly/organization of organic molecules at the solid interface and their comprehensive description is beyond the scope of this section. Some recent reviews of surface self-assembly processes in which the surface is used as a platform are available to the interested reader. ... 

Some interactions that are generally too weak to drive the self-assembly in solution (dipole dipole, C-H- -n, C-H- halogen, Csp2-H N=C ) efficiently can, however, lead to the organization of molecules into well-defined patterns on a surface, under inert atmosphere (UHV). However, in polyfunctionalized molecules, several weak interactions can often compete and the use of such weak and less directional interactions to organize molecules on surfaces leads to less predictable modes of assemblies. Another complication introduced in surface self-assembly is the existence of subtle molecule-surface interactions. This point was recently emphasized by several related cyano-functionalized porphyrins and the smdy of their different assembly modes on Cu(lll). The antiparallel [C=N/N=C] dipolar interactions and C=N- -H-Cortho weak hydrogen bonds favor the formation of chains from the adsorption of 5,15-bis(4-cyanobiphenyl)porphyrins on a Cu(lll) surface (Figure 40). 

FIGURE 16.2 Surfactant molecules at a polar surface self-assemble into aggregates, even at very low surfactant concentration. A monolayer of surfactants, where hydrophobic layers with the surfactant head group facing the surface and the hydrophobic tail facing the aqueous phase, is not formed at the surface, as was earlier believed. The system is cetyl trimethyl ammonium bromide (CTAB), adsorbed on mica, in equilibrium with the bulk concentrations of 10 M, 10" M, and 10 M. (From Sharma, B. G., Basu, S., and Sharma, M. M. 1996. Langmuir 12 6506. With permission.)... 

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