Preparation of electrodes modified with poly(3,4‐ethylenedioxythiophene) nanowires, PEDOT‐nw, was optimized using nanoparticles of dispersed Pt, Pt‐np, to be tested for HCOOH electro‐oxidation. The PEDOT‐nw is electrosynthesized directly on the working electrode, using mesoporous silica as template, by cyclic voltammetry from a 0.01 mol L−1 monomer + 0.1 mol L−1 tetrabutylammonium hexafluorophosphate solution in acetonitrile, on the Pt|PEDOT|mesoporous silica template previously modified electrodes. Using SEM, the presence of PEDOT nanowires with 20 to 25 nm in diameter was verified. In addition, its p‐doping response is about 500 times larger than that obtained on the bulk polymer, maintaining full reversibility of the process. The subsequent electrochemical insertion of Pt‐np and formation of Pt‐np with average diameter of about 20 nm, checked by TEM, demonstrated that the catalytic activity of this nanostructured electrode remarkably enhanced HCOOH electro‐oxidation. The obtained current is up to 2 orders of magnitude higher than previously reported in similar studies, using a much smaller amount of Pt and with a potential decrease greater than 100 mV. Thus, we have at our disposal a simple, inexpensive, and highly reproducible way to prepare in situ nanostructured electrodes using just electrochemical techniques, which can be useful on all the applications of these devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44723.

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Three new polymers, obtained by reacting thiophene or 3-alkylthiophenes as electron donors with aniline as acceptor in a donor-acceptor structure, were synthesized via oxidative polymerization using iron(III) chloride (FeCl 3 ). The final products were characterized utilizing conventional techniques such as IR, NMR, UV-Vis spectrometry, which enabled demonstrating that an increase of the aliphatic chain length causes significant solubility increase of the system, without modifying the conductivity. On the other hand, observed an important variation of the thermal stability of the polymer when medium-length aliphatic chains were inserted was observed; in contrast, the addition of a methyl group (short chain length) hardly affected the mentioned properties.

Two new conjugated polymers, poly(2,3-di(thiophen-2-yl)pyrido [2,3-b]pyrazine) and poly(2,3-di(thiophen-2-yl)pyrido [3,4-b]pyrazine), based on thiophene and pyridine rings were chemically and electrochemically synthesized and characterized by IR, UV-Vis and elemental analysis. Monomers were chemically synthesized at high yield percentages and characterized by FTIR and NMR. Polymers showed p-and n-type doping as well as low bandgap, making them potential candidates for the development of electronic devices.Keywords: 2,3-di(thiophen-2-yl)pyrido [2,3-b]pyrazine, 2,3-di(thiophen-2-yl)pyrido [3,4-b]pyrazine, poly(2,3-di(thiophen-2-yl)pyrido[2,3-b]pyrazine) and poly(2,3-di(thiophen-2-yl)pyrido [3,4-b]pyrazine).

In this work, platinum electrodes are modified with poly[4-(3-hexyl-2-thiophene)-aniline], PTANIr2, and characterized by cyclic voltammetry. In the presence of nitrate in the electrolytic medium, an oxidation signal at 0.6 V vs. SCE is recorded, so the response of this modified electrode, Pt|PTANIr2, is evaluated to determine its relationship with the concentration of the anion. Thus, it is verified that the best response is achieved by chrono-amperometry, obtaining a directly proportional relationship between the charge and the concentration, in an interval between 5 and 100 mg L-1 of the anion, with r 2 = 0.996. Furthermore, it is found that the response of Pt|PTANIr2 is quite selective for nitrate, since there is no response for anions such as HPO4-, PO4 2-, ClO4-, F-, Cl-, Br-, I-, and NO2-, thereby contributing significantly to solving the main problem of devices of this type proposed so far. Finally, the surfaces were characterized by atomic force microscopy, showing a strong anionpolymer layer interaction. Thus, this material can be proposed to be tested as a columbimetric nitrate sensor, highlighting the possibility of varying the area of the electrode and/or the thickness of the deposited polymeric layer and with it, the sensitivity of the device.