Bridges of understanding

The objective of this book is to build bridges of understanding between, on one hand, the chemical structure of polymer molecules and, on the other, the macroscopic technological or engineering behaviour of a plastic or rubber material. We have opted to do this by way of consideration of molecular behaviour, and particularly of the molecular movement and the morphology of the material. By understanding how chemical structure determines the characteristics of molecular motion and morphology, and how these in turn influence the bulk properties, we can link chemistry to materials science in a smooth and informative way. 

In this chapter, the ordered structures that can be found in certain polymer solids are considered. As as presented in Chapter 1, the understanding of the phase morphology of a material is an essential component of the bridges of understanding between chemical structure and physical properties. In addition, the morphology is intimately connected with the various phenomena of molecular motion. Some consequences of this will be developed further in Chapter 9. 

In studies of photochemically induced CT, the energy of the donor and acceptor orbitals are close or higher in energy than the bridge states, and occupation of the bridge is understandable. In contrast, our electrochemical measurements employ redox active intercalators with reduction potentials... 

The explosion of interest in supercritical fluids during the past decade has seen a bridging of these extremes, a movement toward balance. Investigators have sought to understand and develop applications on the basis of underlying physicochemical principles, and recent reports of semi-empirical treatment of supercritical solvent properties have shifted these fluids squarely into the mainstream of chemical research. 

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