Structure-property relations, oligomers

In parallel with polymer synthesis, many activities have been directed towards soluble, well-defined oligomers. Aside from purely synthetic considerations, access to oligomers is, important for the optimization of polymer generation and for the understanding of structure/property relations in the class of PPP... 

II Conjugation alone cannot be relied upon to significantly enhance the optical nonlinearities. The conformational effects and the role of the substituents so that understanding of the molecular structure-property relation can be improved have been studied (89JPC7916). In the case of the thiophene oligomers, a rapid increase in the y value (large microscopic nonlinearity) as a function of N is found. 

Moreover, a variety of other applications in areas such as photovoltaic cells, sensors and solid-state lasers seem very promising and challenging. Future research will surely concentrate on tailor-made materials and hence the development of an understanding of the basic structure-property relation is crucial for a rational design of novel types of cruciform n-conjugated oligomers with improved material properties. 

The industrially produced surfactants used in detergents are applied in formulations containing mixtures of homologs, isomers, and oligomers. As a result, surfactants occur in the environment as mixtures of chemicals which, within a given class, are closely related. Historically, many properties of surfactants have been determined for such mixtures, most frequently without yielding information for the individual constituents. Therefore, much of the existing data, particularly on environmental behavior, does not lend itself for derivation of structure / property relationships and, in consequence, our selection of data here may appear sparse. For some properties, the scarcity reflects the available data. For other properties, we selected data to illustrate how surfactant structure influences environmentally relevant properties. 

Relations between structural properties (nanostructure and texture) and optophysical processes were also established in oligomer thin films. Oligomers of 7r-conjugated polymers with non-degenerate ground state are good computer-... 

The properties that determine whether a product can be labelled as a pressure sensitive adhesive are tack, peel and creep. Tack is the property related to bond formation. Peel defines the tension or force necessary to remove the adhesive tape. Creep is the property describing the flow characteristics of the PSA. Formulators need to be aware of any factors that can directly affect these three properties such as temperature, aging, film thickness, cure rate and post-cure parameters. There are also several formulation variables - these include oligomer selection, tackifier addition, monomer structure, molecular weight and glass transition - that directly impact tack, peel and creep. 

In order to enhance the understanding of the properties in polymers, iterative pathways have been chosen for the synthesis of structurally perfect molecules. Data obtained from the analysis of precisely defined oligomers and polymers may relate chain length and conformation to physical, electronic and optical properties. Statistical polymerization processes are not suitable as they yield polydisperse material. 

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