Polymer, chemical property solvent compatibility

The chemical properties of the CEP structure determine the ability to recognize particular stimuli and respond to them appropriately. In addition, these properties determine how the conducting polymer interacts with other materials in the construction of composite intelligent material structures. Most polymers are capable of, and indeed do, interact with other molecules. Such molecules may be part of larger molecular structures (important in the area of compatible materials), or they may be solvent molecules (such interaction can influence many processes including dissolution) or specific molecules in a solvent or gaseous medium. 

A polymeric substituent on LC polyester should be appropriate to exhibit similar influence as in the case of lateral substituents. Moreover, a polymeric substituent can act as a chemically bound solvent [50]. The compatibility of the polyester rods and a random coil matrix polymer should be significantly increased if a substituent exhibiting the same chemical structure as the matrix polymer is used. This may also lead to the reinforcement of the mechanical properties of the matrix polymer which is akin to fiber reinforced composites. 

Recently, PVDF has become a more popular material to produce hydrophobic membranes through phase inversion processes, mainly for membrane contactor and MD applications. It is preferred to other more hydrophobic polymers, such as polypropylene and polytetrafluoroethylene, because of its excellent combination of properties and its solubility in common organic solvents. Furthermore, the excellent thermal stability of PVDF has made it interesting as a membrane material in a wide range of industrial applications. In addition, unlike other crystalline polymers, PVDF exhibits thermodynamic compatibility with other polymers, such as poly(methyl methacrylate) (PMM A), over a wide range of blend compositions, which can be useful in the fabrication of membrane with desired properties. PVDF can be further chemically modified to obtain specific functions. In addition, it can be cross-linked when subjected to electron beam radiation or gamma radiation. 

As is evident from a consideration of Figs. 7-9, each of these chromophores has exhibited electro-optic activity exceeding that of lithium niobate while at the same time exhibiting auxiliary properties of chemical stability (Td >300 °C) and solubility that permits preparation of device quality materials [183,210-212]. These materials also illustrate another major direction in the preparation of electro-optic materials namely, the development of bridging segments that lead to improved chemical stability, improved solubility in spin-casting solvents, improved compatibility with polymer host materials, and which inhibit unwanted intermolecular electrostatic interactions (we shall discuss such interactions... 

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