Chemical synthesis polyaniline derivatives

ABSTRACT. Detailed experimental procedures are given for the chemical synthesis from aniline of analytically pure emeraldine hydrochloride, a highly conducting polymer derived from the emeraldine oxidation state of polyaniline, which contains equal numbers of oxidized and reduced repeat units, the non-protonated base form of which has the composition,... 

Electronic and photo-active polymers as a class of advanced materials have attracted a lot of interest during last two decades. Typically these materials are synthesized chemically or electrochemically under harsh conditions such as extremely low pH, toxic catalysts and byproducts. New enzymatic approaches have been developed for the synthesis of electro and photo active polymers such as polyanilines, polyazophenols, and polypyrene derivatives. These enzymatically synthesized materials show interesting optical and electronic properties. 

Electroactive polyaniline films were synthesized by the catalysis of biUru-bin oxidase (BOD, a copper-containing oxidoreductase). The polymerization of aniline was carried out on the surface of a sohd matrix such as glass sUde, plastic plate, or platinum electrode to form homogeneous films [33]. The BOD was immobilized on the surface by physical absorption. The optimum pH was around 5.5. Some aniline derivatives such as p-aminophenol and p-phenylenediamine were good substrates for BOD. Structural analysis suggested the BOD synthesized polyanihne possessed partially 1,2-substititued structures. Cyclic voltammetric studies demonstrated that the PANl films were electrochemically reversible in redox properties, but differed from that of chemically or electrochemically synthesized PANl. The difference was attributed to the partial 1,2-substitution. Laccases are known to oxidize phenolic compounds in nature in the presence of oxygen and are capable in polyaniline synthesis in vitro [34-36]. 

A factor hindering the expansion of polyaniline chemistry to date has been the lack of a generic route to variously substituted derivatives. An exciting development in this respect is the recent synthesis of the novel poly(aniline boronic acid). Aromatic boronic acids are versatile chemical precursors undergoing a wide range of transformations, which provides a facile route to a range of substituted PAns that are difficult to synthesize... 

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