Two-dimensional materials

S.L. Thompson, CSQII—An Eulerian Finite Difference Program for Two-Dimensional Material Response—Part 1, Material Sections, SAND77-1339, Sandia National Laboratories, Albuquerque, NM, January 1979. 

For the preparation of two-dimensional materials by reaction of the same type of complex (M=Zn) in anhydrous organic solvent in the presence of 1,6-hexylamine at room temperature, or in the presence of long-chain primary amines near 200 °C [98, 109]... 

Fabrics are two-dimensional materials made from fibers. Their primary purpose is to cover things and they are commonly used in clothes, carpets, curtains, and upholstery. The motive for covering may be aesthetic, thermal, or acoustic. Fabrics are made out of or twisted bundles of fibers. The spinning of yams can occur in two ways staple fibers can be twisted into a thread ( spun yam ) or monofilaments can be twisted into a similar usable thread ( filament yam or continuous filament yam ). All these definitions are important in order to understand the conversation of the fiber industry. 

The polymers and plastics industries are basically concerned with replacing natural flexible and hard one-dimensional and two-dimensional materials. 

For example, consider the two-dimensional array in Figure 15.3. For a two-dimensional material, the function is... 

In a dimensional-analytical discussion of the rheological constitutive equations, Pawlowski [36] furnished the proof that the rank of the dimensional matrix is always two. By a convenient association of the quantities contained in them, two dimensional material parameters can be produced (see Fig. 18) ... 

K and room temperature [74]. Several interpretations of this anomalous pressure dependence have been proposed along with the calculations of the ambient pressure resistivity mentioned previously. The fact that (TSeT)2Cl is an exception and the disappearance of the anomalous pressure dependence of vh at high pressure seems to indicate that it is a specific property of quasi-one- and quasi-two-dimensional materials. 

The sheet silicates or Clay Minerals constitute the largest group of the two-dimensional sfructures in Table 1 All the two-dimensional materials show ion exchange and sorption of neutral molecules like the three-dimensional strnctnres, but with the added feature that the interlayer separation can adjust freely to acconunodate large guest species. Shape selective sorption or molecular sieving is not generally observed except... 

The two-dimensional materials which have been e q)lored as layered precursors for active catalysts include the smectites, hydrotalcites, zirconium phosphates, niobium/titanium and manganese oxides and more recently with the associated interest in the generation of the new hexagonal nano-porous phases, the layered silicates. Each will be dealt with individually in this report. 

The simplest networks are one-dimensional a-networks which may be composed of secondary amides, primary amide dimers or nucleophospholipids. In chapter 5, such structures were discussed as micellar rods and tubules in bulk aqueous solutions. Two-dimensional materials such as copper oxide superconductors, molybdenum sulfide lubricants and intercalated graphites are mostly inorganic. The anisotropic properties are a result of covalent bonds in two dimensions and weak interactions in the third dimension. One may, however, also envision strong hydrogen-bond interactions within an organic layer, whereas adjacent layers are held together only by van de Waals interactions. The two-dimensional, or p-network may form spontaneously from an... 

Pawlowski [428, 429] indicated that the rheological properties of many non-Newtonian fluids can be described by material parameters, whose dimensional matrix had the rank of 2. By reasonable combination these material parameters could be transformed into two dimensional material constants ... 

In evaporation-intercalation devices solar energy conversion would, at least in the more efficient case of a thermal system, not be converted by exciting electrons and rapidly separating them from holes, but by transferring atoms or molecules across a phase boundary by evaporation which is usually a very efficient process. It is, consequently, neither necessary to use materials which are well crystallized like those developed for photovoltaic cells nor is it necessary to prepare sophisticated junctions. A compacted polycrystalline sheet of a two-dimensional material which is on one side placed in contact with an electrolyte, sandwiched between the layer-type electrode and a porous counter electrode, as it is used in fuel cells, would constitute the central energy conversion unit. Some care would have to be taken to choose an electrolyte which is suitable for intercalation reactions and which is not easily evaporated through leaks in the electrodes. Thin layers of polymeric or solid electrolytes would seem to be promising. 

Lanthanide polyoxometalates can be used in conventional s)mtheses to build up two dimensional materials. Linking up lacunary subunits is accomplished by lanthanide binding to terminal oxygen atoms of an adjacent polyoxometalate, forming dimers. The appropriate cations can link the dimers into a lattice, as found in the case of At. ... 

Hydrotalcites are a class of two-dimensional materials consisting of mixed metal hydroxide sheets interspersed with interlayer anions. It is known in the chemistry of hydrotalcites, that it is difficult to synthesize single-phase copper containing hydrotalcites while copper is an important clement explored for various selective oxidation reactions. However, it is also known that Cu-containing hydrotalcites can be synthesized with an addition of another bivalent metal ion. which by itself can independently form hydrotalcites. 

Geim, A. K., and K. S. Novoselov. The Rise of Graphene. Nature Materials 6 (March 2007) 183. This article describes graphenes structure, manufacture, and potential in an entirely new class of two-dimensional materials. 

The majority of recent publications on the investigation of carbon nanostructures are devoted to graphene and its derivatives. Graphene is a monolayer of carbon atoms packed into a dense hexagonal lattice that can be considered as an ideal realization of a two-dimensional material... 

Deng, D., Argon, A. S., and Yip, S. (1989a) A molecular dynamics model of melting and glass transition in an idealized two-dimensional material I, Phil. Trans. Roy. Soc., 329, 549-573. 

Figure 14.12 illustrates the electric conductivity of the selected two-dimensional materials. The data were obtained using a fleld-effect-transistor-fike microscopic device. The authors have measured the carrier mobilities and their density. 

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