The deposition of 4-X phenyl groups (X = NO2, COOH, N-(C2H5)2) on polycrystalline gold electrode was achieved by the electrochemical reduction of the corresponding 4-substituted phenyldiazonium tetrafluoroborate salts in anhydrous acetonitrile media. The electrochemical quartz crystal microbalance measurements evidenced a two-step deposition process: the first one is the deposition of close to a monolayer and the second one is the relatively slower growth of multilayers. In this second region, the deposition is less efficient than for the first one. The electrochemical behavior of the resulting modified gold electrode was investigated in the presence of an electroactive redox probe and these results, together with the electrochemical quartz crystal microbalance data, demonstrated significant differences in reactivity and in deposition efficiency between the diazonium salts. The characterization of the modified electrodes by cyclic voltammetry and electrochemical impedance spectroscopy, as well as X-ray photoelectron spectroscopy measurements, showed that the formation of multilayers is possible and that a significant fraction of the deposited material remained at the electrode surface, even following ultrasonic treatment. The X-ray photoelectron spectroscopy data indicate that the existence of Au-C and Au-N=N-C linkages (where C represents a carbon atom of the phenyl group) is uncertain. Nonetheless, the deposition of the aryl groups by electrochemical reduction of diazonium cations yielded a film that adheres well to the gold surface and the deposited organic film hindered gold oxides formation in acidic medium.

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This study reports on the combination of the electrospinning technique and an adapted vapor-phase polymerization procedure to fabricate PEDOT nanofibers. The fibers have average diameters around 350 nm and are soldered at every intersection of the mat, ensuring a superior dimensional stability. The nanofibers are highly ordered at the molecular level, giving the nonwoven mats a very high conductivity (∼60 S/cm), the highest value reported so far for polymer nanofibers. The mats also demonstrate interesting electrochemical properties due to their porous and nanostructured nature. These conductive nanofibers are expected to be of interest for a number of electronic devices requiring flexibility and/or significant surface area, such as sensors or energy storage systems.

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Thin films of poly(styrene-b-4-vinylpyridine) (PS4VP) [M n(PS) = 71.9 kg/mol; M n(P4VP) = 30.2 kg/mol] mixed with 1,5-dihydroxynaphthalene (DHN) were dip-coated onto flat substrates from THF solutions. The resultant nanostructures were characterized by AFM, TEM, infrared spectroscopy, contact angle measurements, and cyclic voltammetry. The DHN selectively enriches the P4VP domains through hydrogen bond complexation, giving relative block compositions that should result in lamellar morphology in the bulk. However, films dip-coated from solutions of variable DHN:4VP molar ratios self-assemble into a quasi-hexagonal array of nodules of P4VP + DHN protruding above a PS matrix. This morphology can be ascribed, at least in part, to greater solubility in THF of PS compared to P4VP. The solubility difference appears to be highest for equimolar DHN:4VP. The removal of DHN from the deposited films by rinsing with methanol creates regularly patterned nanoporous films. The geometric parameters of the nanopatterns before and after DHN removal depend on the DHN:4VP ratio. Electrochemical measurements indicate that the pores penetrate the methanol-rinsed films most deeply for those prepared using an initial DHN:4VP molar ratio of 4:1. It was estimated from these measurements that a P4VP layer of about 2 nm thick is located at the film−substrate interface, through which electron tunneling can occur.