Surfacant directed self assembly

A large number of potential applications for organized protein monolayers have recently motivated considerable research activity in this field (Boussaad et al. 1998, Kiselyova et al. 1999). Construction of specific interaction-directed, self-assembled protein films has been performed at the air-water interface. The Langmuir-Blodgett (LB) technique has been extensively used to order and immobilize natural proteins on solid surfaces (Tronin et... 

Chemically Directed Self-Assembly of Nanoparticle Structures on Surfaces... 

In this review, we describe the recent developments of chemically directed self-assembly of nanoparticle structures on surfaces. The first part focuses on the chemical interactions used to direct the assembly of nanoparticles on surfaces. The second part highlights a few major top-down patterning techniques employed in combination with chemical nanoparticle assembly in manufacturing two- or three-dimensional nanoparticle structures. The combination of top-down and bottom-up techniques is essential in the fabrication of nanoparticle structures of various kinds to accommodate the need for device applications. 

This chapter describes the self-assembly of non-native protein fibers known as amyloid fibrils and the development of these fibrils for potential applications in nanotechnology and biomedicine. It extends an earlier review by the author on a related topic (Gras, 2007). In Section 1, the self-assembly of polypeptides into amyloid fibrils and efforts to control assembly and any subsequent disassembly are discussed. In Section 2, this review focuses on the important role of surfaces and interfaces during and after polypeptide assembly. It examines how different surfaces can influence fibril assembly, how surfaces can be used to direct self-assembly in order to create highly ordered structures, and how different techniques can be used to create aligned and patterned materials on surfaces following self-assembly. 

As distinct from sohd supports such as gold or silver, mercury imparts lateral mobihty to hpid monolayers directly self-assembled on its surface, because of its liquid state. This is demonstrated by rapid spontaneous phase separation, with microdomain formation, in a hpid mixture monolayer self-assembled on top of a DPTL thiolipid monolayer tethered to a mercury microelectrode [30]. The presence of microdomains was directly verified from the images of the distal hpid monolayer obtained using two-photon fluorescence lifetime imaging microscopy. 

Kocharova K, Aaritalo T, Leiro J (2007) Aqueous dispersion, surface thiolation, and direct self-assembly of carbon nanotubes on gold. Langmuir 23 3363-3371... 

The formation of self-assembled monolayers (SAMs) on solid surfaces must be clearly distinguished from this case since a part of the spatial information required is provided by the surface. This case can be regarded as directed self-assembly of building blocks, which involves structure-directing additives, for example the solid surface. It is clearly distinct from spontaneous self-assembly and can rather be thought of being closely related to a template-assisted process. This may be rationalized by the pattern formation of a molecular layer on different surface orientations of the same material, which leads us to the concept of template-assisted assembly. 

Brinker and coworkers also prepared photoresponsive nanoporous silica particles using aerosol-assisted assembly, EISA, and surfactant-directed self-assembly (SDSA) techniques (Liu, 2004). The as-prepared photoresponsive nanocomposite particles were prepared so that the azobenzene ligands pointed toward the hydrophobic micellar interiors. After surfactant removal by solvent extraction, nanoporous particles with azobenzene ligands positioned on the pore surfaces were formed (Fig. 13.8). 

Figure 1 depicts structures of nanotubes that have so far been derived from block copolymer self-assembly. While the nanotubes are drawn as being rigid and straight, they, in reality, can bend or contain kinks. The top scheme depicts a nanotube formed from either an AB diblock copolymer [15,16] or an ABA triblock copolymer [17], where the gray B block forms a dense intermediate shell and the dark A block or A blocks stretch into the solvent phase from both the inner and outer surfaces of the gray tubular sheU. Such tubes have been prepared so far from the direct self-assembly or tubular micelle formation of a few block copolymers in block-selective solvents, which solubilize only the dark A block or blocks. Nanotubes with structures depicted in the middle and bottom schemes have been prepared from precursory ABC triblock copolymer nanofibers, which consist of an A corona, a cross-linked intermediate B shell, and a C core [18] A fully empty tubular core was ob-... 

Hahner and coworkers [441] have described the preparation and characterization of SAMs of longacid esters on oxide surfaces of Ti, Al, and Nb from an organic solvent. They have focused on a direct determination of the orientation and order of acid monolayers on the surface. Octadecanephosphoric acid was dissolved in n-heptane/propan-2-ol (100 0.4 (v/v)) solvent mixture at 0.5 mM concentration. SAMs were formed by immersion of the substrates in the solution for up to 48 h. Following immersion, the substrates were removed from the solution and rinsed with propan-2-ol, blow-dried with N2, and stored in air until analysis. The preparation of well-ordered SAMs from heptane/propan-2-ol is apph-cable to various oxide substrates covered by alkanephosphates. This might open up the possibility of chemically tailoring many technologically important oxide surfaces via self-assembly. 

Of relevance to this section, Reculusa et al. also recently demonstrated that the addition of a small amount (only 1.5 pmole/m ) of a monomethylether mono methylmethacrylate poly(ethylene oxide) macromonomer (structure 9, Table 4.5) allowed the direct self-assembly of nanometric polystyrene latex particles on the surface of submicronic sihca particles through an in-situ nucleation and growth process (Fig. 4.12) [102]. The two sets of particles were assembled in a raspberry-like morphology via the formation of hydrogen bonds at the interface of the inorganic and organic coUoids. The size and shape of the assembly can be easily controlled by varying the sizes and stoichiometries of the colloidal components (Fig. 4.13). 

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