Nanometer scale materials

In this chapter we review the application of MD techniques to the study confined thin films under shear. Three properties of particular interest are friction, shear viscosity, and flow boundary condition. For nanometer-scale material properties such as indentation and adhesion, we refer the reader to a recent review by Harrison and Brenner [49],... 

Y. Nishina, M. Mizuta, and H. Kamimura, Eds., Physics and Chemistry of Nanometer-Scale Materials, Elsevier, Sequoia, 1993. 

The process of self-assembly not only occurring in solution but also on metallic surfaces leads to supramolecular structures with specific properties which lie at the root of what we term molecular materials or nanometer scale materials. Those that will be described here are enantiopure, and we will explore their principal features. This chemistry is in its infancy, and while concrete results in terms of properties are still modest, the rapid growth in these chiral materials is such that their applications are becoming promising. An appraisal of the chemistry of chiral molecular materials is the subject of Chapter 6 (Figure 1.3). 

The nanopalpation technique, nanometer-scale mechanical and rheological measurement based on AFM, was introduced and shown to be useful in analyzing nanometer-scale materials properties for the surfaces and interfaces of polymer nanoalloys and polymer-based nanocomposites. It enables us to obtain not only structural information but also mechanical information about a material at the same place and time. 

The most contemporary chemical physics methods and principles are applied to the characterization of these ten properties. The coverage is broad, ranging from the study of biopolymers to the analysis of antioxidant and medicinal chemical activity, on the one hand, to the determination of the chemical kinetics of not chemical systems and the characterization of elastic properties of novel nanometer scale material systems, on the other. 

Advances in Kinetics and Mechanism of Chemical Reactions describes the chemical physics and/or chemistiy of 10 novel material or chemical systems. These 10 novel material or chemical systems are examined in the context of issues of stmeture amd bonding, and/or reactivity, and/or transport properties, and/or polymer properties, and/ or biological characteristics. This eclectic survey thus encompasses a special focus on the associated kinetics, reaction mechanisms and/or other chemical physics properties, of these 10 broadly chosen material or chemical systems. Thus, the most contemporary chemical physics methods and principles are applied to the characterization of the properties of these 10 novel material or chemical systems. The coverage of these novel systems is thus broad, ranging fiom the study of biopolymers to the analysis of antioxidant and medicinal chemical activity, on the one hand, to the determination of the chemical kinetics of novel chemical systems, and the characterization of elastic properties of novel nanometer scale material systems, on the other hand. 

Information on the morphology of the nanohybrid sorbents also was revealed with SEM analysis. Dispersed spherical polymer-silica particles with a diameter of 0.3-5 pm were observed. Every particle, in one s turn, is a porous material with size of pores to 200 nm and spherical particles from 100 nm to 500 nm. Therefore, the obtained samples were demonstrated to form a nanometer - scale porous structure. 

Carpick, R.W., Enachescu, M., Ogletree, D.F. and Salmeron, M., Making, breaking, and sliding of nanometer-scale contacts. In Beltz, G.E., Selinger, R.L.B., Kim, K.-S. and Marder, M.P., (Eds.), Fracture and Ductile vs. Brittle Behavior-Theory, Modeling and Experiment. Materials Research Society, Warrendale, PA, 1999, pp. 93-103. 

Besides the classical search for linear, one-dimensional electronically active materials, synthetic approaches are now also focussed on the generation and characterization of two- and three-dimensional structures, especially shape-persistent molecules with a well-defined size and geometry on a nanometer-scale. It is therefore timely and adequate to extend concepts of materials synthesis and processing to meet the needs defined by nanochcmislry since the latter is now emerging as a subdiscipline of material sciences. 

The above-mentioned AFM capabilities wUl enhance characterization of soft materials at the nanometer scale and will make this method invaluable for researchers working in academia and industry. 

Recent demands for polymeric materials request them to be multifunctional and high performance. Therefore, the research and development of composite materials have become more important because single-polymeric materials can never satisfy such requests. Especially, nanocomposite materials where nanoscale fillers are incorporated with polymeric materials draw much more attention, which accelerates the development of evaluation techniques that have nanometer-scale resolution." To date, transmission electron microscopy (TEM) has been widely used for this purpose, while the technique never catches mechanical information of such materials in general. The realization of much-higher-performance materials requires the evaluation technique that enables us to investigate morphological and mechanical properties at the same time. AFM must be an appropriate candidate because it has almost comparable resolution with TEM. Furthermore, mechanical properties can be readily obtained by AFM due to the fact that the sharp probe tip attached to soft cantilever directly touches the surface of materials in question. Therefore, many of polymer researchers have started to use this novel technique." In this section, we introduce the results using the method described in Section 21.3.3 on CB-reinforced NR. 

In this chapter, AFM palpation was introduced to verify the entropic elasticity of a single polymer chain and affine deformation hypothesis, both of which are the fundamental subject of mbber physics. The method was also applied to CB-reinforced NR which is one of the most important product from the industrial viewpoint. The current status of arts for the method is still unsophisticated. It would be rather said that we are now in the same stage as the ancients who acquired fire. However, we believe that here is the clue for the conversion of rubber science from theory-guided science into experiment-guided science. AFM is not merely high-resolution microscopy, but a doctor in the twenty-first century who can palpate materials at nanometer scale. 

The overall objective of this chapter is to review the fundamental issues involved in the transport of macromolecules in hydrophilic media made of synthetic or naturally occurring uncharged polymers with nanometer-scale pore structure when an electric field is applied. The physical and chemical properties and structural features of hydrophilic polymeric materials will be considered first. Although the emphasis will be on classical polymeric gels, discussion of polymeric solutions and nonclassical gels made of, for example, un-cross-linked macromolecular units such as linear polymers and micelles will also be considered in light of recent interest in these materials for a number of applications... 

Figure 1.4. Catalysts are nanomaterials and catalysis is nanotechnology. If we define nanotechnology as the branch of materials science aiming to control material properties on the nanometer scale, then catalysis represents a field where nanomaterials have been applied commercially for about a century. Many synthetic techniques are available to...

As has been shown above, oscillatory electrodeposition is interesting from the point of view of the production of micro- and nanostructured materials. However, in situ observation of the dynamic change of the deposits had been limited to the micrometer scale by use of an optical microscope. Inspections on the nanometer scale were achieved only by ex situ experiments. Thus, information vdth regard to dynamic nanostructural changes of deposits in the course of the oscillatory growth was insufHcient, although it is very important to understand how the macroscopic ordered structures are formed with their molecular- or nano-components in a self-organized manner. 

When any materials interact with their environment through solid/gas, solid/liquid, and solid/solid interfaces, the nanometer scale surface created can easily be modified to perform certain functions. The modifications are usually only effective in the few nanometer deep surface layers. This chapter highlights the development of new model nanostructured materials with functionalized interfaces to... 

When a liquid-liquid interface is to be investigated using an electrode in the more dense phase, or for studies at the water-air interface, a submarine electrode can be deployed [18,19,34], depicted schematically in Fig. 3(b). In this case, the electrode is inverted in the cell, such that the tip points upwards, and an insulated connection is made through the solution. Metal electrodes down to the nanometer scale can also be fabricated by sealing an etched Pt or Pt-Ir wire in a suitable insulating material, leaving just the etched end exposed [35-37]. 

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