Polypyrroles, assembly temperature

The LB technique may also be combined with solid-state chemistry methods to produce novel molecular architectures. For example, a network of conductive polypyrrole (molecular wires ) may be obtained in a fatty acid matrix [37, 38]. First, monolayers of the iron salt of a long-chain fatty acid (e.g., ferric pahnitate) are assembled on an appropriate substrate. The multilayer film is then exposed to saturated HCl vapor at room temperature for several minutes. During this process, a chemical reaction transforms the fatty acid salt into layers of ferric chloride separated by layers of fatty acid. In the third and final step, the film is exposed to pyrrole vapor and a reaction occurs between the pyrrole and the ferric chloride, producing polypyrrole distributed within the multilayer assembly. 

Fig. 37.2 (A) Schematic illustration showing a conductive polymer/high-temperature superconductor sandwich device. To create such a structure, a YBa2Cu307-s thin film is deposited onto a MgO(lOO) substrate via laser ablation, a microbridge is patterned on the central portion of the film, and a conductive polymer layer is deposited electrochemi-cally onto the microbridge area. (B) Cyclic voltammetry (5 mV/s) recorded at room temperature in 0.1 M Et4NBp4/ acetonitrile for a YBa2Cu307-s thin-film electrode assembly coated with polypyrrole. Well-behaved voltammetry is observed, indicating that electronic charge flows readily between the superconductor and the polymer layer. (Adapted from Ref. 11.)...

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