Electrical, Optical, and Magnetic Properties

The relative permittivities e (at 25°C) of the hquid solvents and their temperature derivatives, (deldT)p, taken from [3], are listed in Table 3.5. 

TABLE 3.5 The Relative Permittivities of Solvents at 25°C and Ambient Pressnre, e, and their Temperatnre and Pressnre Derivatives deldT) and (de/dP)., their Refractive Indexes, their Polarizabilities, a, and their Dipole Moments, [i 

Less widely available is the pressure derivative of the permittivity deldP and is provided in Table 3.5 where known [4], For solvents that have no entries in the (5e/9P)j, column, the values may be estimated from  

The refractive index (at the sodium D-line, 589 nm), n, the range of which for the solvents listed is fairly narrow, from 1.3265 for methanol to 1.550 for nitrobenzene, is also listed in Table 3.5. From the refractive index is derived the molar refraction by means of the Lorenz-Lorentz expressions  

These values cover a much larger range because of the dependence on the molar volume, namely from / ycm mol = 3.8 for water to 47.7 for HMPT. The polarizability, a, of the molecules of the solvent is proportional to the molar refraction  

---

R. Saito, M. Fujita, G, Dresselhaus, and M. S. Dresselhaus, In Electrical, Optical and Magnetic Properties of Organic Solid State Materials, MRS Symposia Proceedings, Boston. Edited by L. Y. Chiang, A. F. Garito, and D. J. Sandman, vol, 247, p. 333, Pittsburgh, PA, Materials Research Society Press (1992),... 

Secondly, the electron theory seeks to elucidate the relation between the catalytic and electronic properties of a semiconductor. At the present time we possess a vast amount of experimental material which allows us to infer that the electronic processes taking place in a semiconductor and determining its electrical, optical, and magnetic properties also determine its chemisorptive and catalytic properties. It is the aim of the theory to establish the connection between these two groups of properties. 

The physical properties of solvents greatly influence the choice of solvent for a particular application. The solvent should be liquid under the temperature and pressure conditions at which it is employed. Its thermodynamic properties, such as the density and vapor pressure, temperature and pressure coefficients, as well as the heat capacity and surface tension, and transport properties, such as viscosity, diffusion coefficient, and thermal conductivity, also need to be considered. Electrical, optical, and magnetic properties, such as the dipole moment, dielectric constant, refractive index, magnetic susceptibility, and electrical conductance are relevant, too. Furthermore, molecular... 

The application of band theory to account for detailed electrical, optical and magnetic properties has so far had only limited success (28). Electronic conduction and optical absorption resulting in the onset of u.v.-visible opaqueness involve the transference of electrons from one ion to another, and it would therefore seem worth applying the principles of optical electronegativity to these problems. Any resulting correlations are expected to be of a much more qualitative nature than results given by applying band theory. 

RL White, YY Hsu, TM Cooper, JD Greeser, DL Wise, DJ Trantolo. Mater Res Soc Symp Proc 488 (Electrical, Optical, and Magnetic Properties of Organic Solid-State Materials IV) 453, 1998. 

Table 3.5 Electric, optical, and magnetic properties of solvents...

Garito AF, Jen AKY, Lee CYC, Dalton LR (eds) (1994) Electrical, optical, and magnetic properties of organic solid state materials, vol 328. Materials Research Society, Pittsburgh... 

G. Bongiovanni, S. Destri, A. Mura, A. Piaggi, and R. Tubino, Mater. Res. Soc. Symp. Proc., 1996, 413 (Electrical, Optical and Magnetic Properties of Organic Solid State Materials), 589. 

The unique properties of polymers such as polyacetylene, whose backbones consist of an alternating succession of single and double bonds, and most of which show extraordinary electrical, optical and magnetic properties including electrical conductivity when "doped" with electron donors or acceptors [35], are also outside the scope of this work. Sophisticated quantum mechanical treatments are required to predict these properties of such polymers. 

The main interest of mesophases based on mineral moieties is, in contrast to their organic counterparts, that they can be electron rich and so have enhanced electrical, optical, and magnetic properties. In addition, mineral moieties are thermally very stable. Thus, combined with their typically very wide range of temperature stability of mesomorphic organization, it can be envisaged that they can be used for applications under extreme conditions. Another important and common asset of these MLC is their very low cost since some of them can even be found in a natural form. This will allow their use for massive material production. 

A crystal composed of such densely packed independent stacks of planar molecules must necessarily have unique anisotropic properties. There are indeed a number of purely organic and also organometallic materials which fulfill the above requirements and which seem to be onedimensional metals. At present, these materials provide excitement and stimulus to physicists since they allow the study of physics in one dimension (anisotropic electrical, optical, and magnetic properties) and also offer the only promising possibility of obtaining high temperature superconductors. For technical applications, anisotropic properties may be a problem as well as a particularly useful asset. 

Equation (1) indicates that, in order to comply with the second law, the volume of a material must decrease upon isothermal compression. The precise maimer, however, in which a material reduces its volume in response to an applied pressure is unspecified by the second law and requires consideration on a molecular level. Molecular attributes such as bond angles, bond lengths, covalency, coordination number, and intermolecular forces can be influenced by pressure. Since these attributes are responsible for defining chemical, electrical, optical, and magnetic properties, pressure is a potentially powerful probe of the properties of materials. 

Finally, soHd-state physicists make use of molecular crystals when they wish to understand certain aspects of soUd-state physics better theoretically and experimentally. Weak intermolecular bonding forces, electrical conductivity with a very narrow handwidth, large anisotropies in their electrical, optical and magnetic properties, one-dimensional conductivity. Unear excitons, and linear magnetic ordering states are best studied in these material classes. 

A more fruitful approach has been to make stacked phthalocyanine polymers with oxygen bridges between the metals. Dehydration of phthalocyanine complexes of Si, Ge and Sn produces a face-to-face oxygen bridged stacking pattern shown in Scheme Since electrical, optical and magnetic properties of... 

Ceramic materials are attractive for several reasons. The starting materials for making them are readily available and cheap. Ceramics are lightweight in comparison with metals and retain their strength at temperatures above 1000°C, where metal parts tend to fail. They also have electrical, optical, and magnetic properties of value in the computer and electronic industries. 

ELECTRICAL, OPTICAL AND MAGNETIC PROPERTIES OF POLYANILINE PROCESSED FROM SULFURIC ACE) AND IN SOLUTION IN SULFURIC ACE)... 

Conductivity in conjugated polymers was discovered several decades ago [1]. Since then, there has been major advances in the synthesis, characterization and applicability of conjugated polymers for different device applications. They all have in common a conjugated bond structure that allows for electron delocalization and charge transport along the polymer backbone resulting in unique electrical, optical and magnetic properties. Molecular structures for some commonly used CPs are shown in Fig. 7.1. 

Semiconducting one-dimensional (ID) nanolibers or nanowires are of interest for a wide variety of applications including interconnects, functional devices, and molecular sensors as well as for fundamental physics studies. Devices have been fabricated fi om semiconductor, and carbon nanotubes, and more recently from ICP nanofibers. It has been predicted that ICP nanofibers will have unique electrical, optical, and magnetic properties [134]. Several different methods for producing these ICP nanofibers have been developed with or without the aid of a template. The template-based methods involve synthesizing a tubular structure of the ICP within the pores of a support membrane, such as an alumina membrane [135] or a track-etched polycarbonate membrane [136]. However, more recent work has... 

On the other hand carbon nanotubes (CNT) have been the subject of extensive investigation due to their remarkable properties such as very high aspect ratio, excellent mechanical, electrical, optical and magnetic properties. To exploit the properties of carbon nanotubes, efficient exfoliation of the CNT bundles in the polymer matrix is a prerequisite. There are various methods aimed at efficient exfoliation of CNT either in polymer or solvent [7-10]. In addition, nanocomposites... 

During the Stone Age, the material research was limited to the mechanical treatment of natural products. When Dalton discovered atomicity and Mendeleev revealed the periodic table, the research trends drastically changed in the intervening period and research was focussed on fundamental principles of basic molecular structure and simple chemical reactions. During the late twentieth century and the early twenty-first century, an exciting revolution in chemistry has taken place, with multidisciplinary approaches in nanoscience and nanotechnology to the creation of molecules with pre-specified complex structures to perform novel functions, hi the present century, research is focussed on control of crystal structures, nanostractures and microstructures with distinct mechanical, electrical, optical and magnetic properties [1-5]. 

---