Dawei Gu

Chemical In Situ Polymerization of Polypyrrole Nanoparticles on the Hydrophilic/Hydrophobic Surface of SiO2 Substrates

Polypyrrole (PPy) nanoparticles formed by chemical in situ polymerization were deposited on the hydrophilic/hydrophobic surface of SiO2 substrates to give the diversely morphology, respectively. The morphologies of PPy nanoparticles deposit were investigated using optical microscope, scanning electron microscope (SEM), and atomic force microscope (AFM) imaging techniques. The morphology of Y- and T-shape wrinkles was observed on the hydrophilic surface of SiO2 substrate, while the morphology of polygon-shape wrinkles on the hydrophobic surface of SiO2 substrate, and this distinction is due to the difference of the surface energy between the hydrophilic and hydrophobic surface of SiO2 substrate and so-called “memory effect.”

Preparation, Characterization, and Conductivity of Polyaniline Doped with 12-Tungstoboric Acid

The Keggin type 12-tungstoboric acid (H5BW12O40) was prepared. Aniline was oxidized in an aqueous solution of H5BW12O40 to synthesize a series of polyanilines doped with the 12-tungstoboric acid (PANI-[H5BW12O40]), using ammonium persulfate as an oxidant. The effects of the initial weight ratio x (x) of H5BW12O40 to aniline on the properties of PANI-[H5BW12O40] were investigated by FTIR, UV-vis, XRD, and conductivity measurement. The results showed that PANI in PANI-[H5BW12O40] was in the emeraldine salt state, and the 12-tungstoboric anions were incorporated into the chains of PANI more and more with increasing values of x. The oxidation degree of PANI in PANI-[H5BW12O40] was strongly dependent on x. As the weight ratio x reached 0.040, the oxidation degree of PANI in PANI-[H5BW12O40] increased obviously. The reason that electrical conductivity of PANI-[H5BW12O40] decreased sharply at x was attributed to the increase of the oxidation degree resulted by the excess of H5BW12O40 used in the preparation.

Synthesis of Novel 2-amino-6-oxo-3-(piperidinyla- midino)-4-aryl-6,7-dihydro-pyrano(2,3-d)-5,7-thiazol Derivatives by Domino Reaction under Microwave Irradiation

Seven novel 2-amino-6-oxo-3-(piperidinylamidino)-4-aryl-6,7-dihydro-pyrano[2,3-d]-5,7-thiazol derivatives, which are different with the products of 2-amino-3-cyano-6-oxo-4-aryl-6,7-dihydropyrano[2,3-d]-5,7-thiazol derivatives in the conventional heating conditions, were synthesized by using arylidenemalononitrile, 2,4-thiazolidinedione and piperidine in one-pot via microwave irradiation techniques. The reaction condition is mild and we get these new compounds highefficiently in a very short reaction times, which provides an elegant methodology for the synthesis of highly functionalized pyrano[3,2-d]-5,7-thiazole derivatives. At the end, the reaction mechanism was

Improvement of Electron Transport Properties of Polypyrrole Nano-films by In-situ Polymerization under High Pressure

The conducting polypyrrole (PPy) nanofilms have been in-situ polymerized on quartz substrates under various high reaction pressures (0.1–600 MPa). The effects of the applied pressure on films have been carefully investigated through UV-Vis, FT-IR, SEM, AFM and conductivity measurement. The effect of the applied pressure on the thickness and the electrical conductivity of the PPy films have been discussed. A three-dimensional relationship between film thickness, reaction pressure, and the conductivity of the films has also been described in text. Our results may provide a guide for studying in-situ polymerization of pyrrole and its derivatives under high reaction pressure.