Hybrid periodic structures

Zhang, J. Coombs, N. Kumacheva, E., A new approach to hybrid nanocomposite materials with periodic structures, J. Am. Chem. Soc. 2002, 124, 14512 14513... 

Owing to the simphcity and versatility of surface-initiated ATRP, the above-mentioned AuNP work may be extended to other particles for their two- or three-dimensionally ordered assemblies with a wide controllabiUty of lattice parameters. In fact, a dispersion of monodisperse SiPs coated with high-density PMMA brushes showed an iridescent color, in organic solvents (e.g., toluene), suggesting the formation of a colloidal crystal [108]. To clarify this phenomenon, the direct observation of the concentrated dispersion of a rhodamine-labeled SiP coated with a high-density polymer brush was carried out by confocal laser scanning microscopy. As shown in Fig. 23, the experiment revealed that the hybrid particles formed a wide range of three-dimensional array with a periodic structure. This will open up a new route to the fabrication of colloidal crystals. 

An overview of our original works in the field of precise cylindrical nanoshells (nanotubes, nanospirals, and nanorings) self-formed from Ill-V single crystals and Si/GeSi heterofilms and from metal-semiconductor, metal-metal and hybrid films is presented. New results are described on the formation of spatially periodic structures, open and closed single-crystal 3D nanoshells of various shapes with the minimum radius of curvature of 1 nm, and also on assembling these shells in even more complex architectures. 

There is another class of frictional interaction that we might call semi-deterministic. These actually behave like a hybrid between stick/slip oscillations and random peak/valley fiiction interactions. Most of these semi-deterministic interactions are caused by human-made objects, created through intentional engineering of the surface features of these objects. Essentially any surface that has a deterministic (especially periodic) structure has the potential to slide with a quasi-periodic motion. Some obvious examples of these come from our driving experience, like the ka-dunk, ka-dunk... sound produced by the seams between freeway concrete tiles, or the scored pavement patterns (or Botts dots) placed by the road edges to tell us we re straying from the allowed driving surface. 

Fig. 36 Synthesis of poly(MMA-co-MAA)/CdS/poly(MAA-co-BA) muttitayered hybrid particies with a periodic structure. Redrawn and adapted from [315] with permission of the American Chemical Society...

Similarly, using the same particles as those used for the synthesis of CdS QDs (see Sect. 6.2, Fig. 36), silver nanoparticles could be deposited onto carboxylated poly(MMA-co-MAA) particles using silver salts as precursors [315, 316]. As for the case of CdS, periodic structures of polymer/silver hybrid colloids were elaborated. The method obviously opens a new avenue for production of optically responsive materials with a controlled periodicity. In another work using commercial llOnm carboxylate-functionalized PS particles as templates, Hao et al. reported the synthesis of silver nanodisks formed through chemical reduction of silver salts in DMF [332]. The composite particles obtained (Fig. 39) exhibited an intense electronic spectrum differing markedly from those of spheres. Still using... 

Yabu, FI., Inoue, K., Shimomura, M. Multiple-periodic structures of self-organized honeycomb-patterned films and polymer nanoparticles hybrids. Colloid Surf. A 284-285, 301-304 (2006)... 

Further support and interest in my work was shown by Dr. Brian Kent, Dr. Stephen Schneider, and Mr. Ed Utt from the U.S. Air Force. After completion of the development of the Periodic Method of Moments, the PMM code, the Hybrid radome, low RCS antennas, and more, the funding from the Air Force shifted into more hardware-oriented programs. Fortunately, the U.S. Navy needed our help in designing very broadbanded bandstop panels. Ultimately, this work resulted in the discovery of surface waves unique to finite periodic structures, which are treated in great detail in this book. The help and advice from Mr. Jim Logan, Dr. John Meloling, and Dr. John Rockway is deeply appreciated. 

Hybrid approaches combining ab-initio or DFT and semiempirical approaches have become popular. As an example, we can refer to LEDO (hmited expansion of differential overlap) densities application to the density-functional theory of molecules [262]. This LEDO-DFT method should be well suited to the electronic-structure calculations of large molecules and in the anthors opinion its extension to Bloch states for periodic structures is straightforward. In the next sections we discuss the extension of CNDO and INDO methods to periodic stmctures - models of an infinite crystal and a cyclic cluster. 

Miktoarm star ABC triblock copolymers are found to exhibit a rich phase behavior as a function of the film thickness and the surface field when cast as thin films. SCFT has been used to describe the geometric confinement of the films between two identical parallel surfaces.Particularly, for the parameter range analyzed, complex hybrid network structures in thin films of bulk cylinder-forming star copolymers were found when the natural domain period does not commensiuate with the film thickness, in contrast to the arrangement of cylinders perpendicular to the surface or PL/lamellae found in linear copolymers. 

The element before carbon in Period 2, boron, has one electron less than carbon, and forms many covalent compounds of type BX3 where X is a monovalent atom or group. In these, the boron uses three sp hybrid orbitals to form three trigonal planar bonds, like carbon in ethene, but the unhybridised 2p orbital is vacant, i.e. it contains no electrons. In the nitrogen atom (one more electron than carbon) one orbital must contain two electrons—the lone pair hence sp hybridisation will give four tetrahedral orbitals, one containing this lone pair. Oxygen similarly hybridised will have two orbitals occupied by lone pairs, and fluorine, three. Hence the hydrides of the elements from carbon to fluorine have the structures... 

The Universal Force Field, UFF, is one of the so-called whole periodic table force fields. It was developed by A. Rappe, W Goddard III, and others. It is a set of simple functional forms and parameters used to model the structure, movement, and interaction of molecules containing any combination of elements in the periodic table. The parameters are defined empirically or by combining atomic parameters based on certain rules. Force constants and geometry parameters depend on hybridization considerations rather than individual values for every combination of atoms in a bond, angle, or dihedral. The equilibrium bond lengths were derived from a combination of atomic radii. The parameters [22, 23], including metal ions [24], were published in several papers. 

Methodologies for the de novo design and synthesis of polypeptides were recently developed. The preparation of periodic polypeptides, polypeptides containing artificial amino acids, polypeptides exhibiting rodlike structures, and hybrids of natural and artificial polypeptide segments was recently described [33],... 

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