Conjugated polymers, bonding conducting

In addition to thermal polymerization, it is possible to polymerize CPD with inorganic haUdes as catalyst. With trichloroacetic acid as the catalyst, deeply colored, blue polymers that conduct electricity in nonpolar solvents such as benzene in the presence of acid can be obtained. The conductivity and color are caused by blocks of conjugated double bonds present in the polymers (20—21). 

Since the discovery of doped polyacetylene, a range of polymer-intense semiconductor devices have been studied including normal transistors and field-effect transistors (FETs), and photodiodes and light-emitting diodes (LEDs). Like conductive polymers, these materials obtain their properties due to their electronic nature, specifically the presence of conjugated pi-bonding systems. 

In real tran -polyacetylene, the structure is dimerized with two carbon atoms in the repeat unit. Thus the tt band is divided into occupied tt and unoccupied n bands. The bond-alternated structure of polyacetylene is characterishc of conjugated polymers. Consequently, since there are no partially filled bands, conjugated polymers are expected to be semiconductors, as pointed out earlier. However, for conducting polymers the interconnection of chemical and electronic structure is much more complex because of the relevance of non-linear excitations such as solitons (Heeger, 2001). 

Warman JM, de Haas MP, Dicker G, Grozema FC, Ptris J, Debije MG (2004) Charge mobilities in organic semiconducting materials determined by pulse-radiolysis time-resolved microwave conductivity 7c-bond-conjugated polymers versus tc—tc-stacked discotics. Chem Mater 16 4600... 

Balabanov, E. I., A. A. Berlin, V. P. Parini, V. L. Tal Roze, E. L. Franke-vich, and M. I. Cherkashina Electrical conductivity of polymers with conjugated double bonds. Dokl. Akad. Nauk. 134, 1123 (1960). 

Conducting polymers based on polymer chains with conjugated double bonds are electroactive materials that have found widespread use also in the field of chemical sensors [11-41], Oxidation of the conjugated polymer backbone is accompanied by anion insertion or cation expulsion, as follows ... 

Polymeric (SN)X has some unusual properties. For example, it has a bronze color and metallic luster, and its electrical conductivity is about that of mercury metal. Values of the conductivity of (SN) depend on the purity and crystallinity of the polymer and on the direction of measurement, being much greater along the fibers than across them. A conjugated single-bond/double-bond system can be formulated, in which every S-N unit has one antibonding tt electron. The half-filled overlapping tt orbitals combine to form a half-filled conduction band, in much the same way as the half-filled ns orbitals of alkali metal atoms... 

What would it take to make the polymer itself conducting To start, we would need to make a polymer with a long series of interacting double bonds (called conjugated unsaturation). Three examples are polyacetylene, poly(p-phenylene), and polythiophene ... 

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