A simple two-phase route to silver nanoparticles/polyaniline structures

Novel silver nanoparticles/polyaniline composites were obtained through a two-phase water/toluene interfacial reaction. We show that by rigorously controlling the reaction time, different structures of the nanocomposites can be obtained, such as a thin sheet of polyaniline around the silver nanoparticles or a polymer mass with nanoparticles homogeneously embedded within it. Samples were characterized by FT-IR, UV-vis-NIR and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, TEM, and HRTEM. Conductivity and current-voltage characteristics of the nanocomposites were measured, and the results indicate that different properties result from the different structures in which the nanocomposites were formed.     

Pyridinium chlorochromate oxidation route to polyaniline

In this work, for the first time, pyridinium chlorochromate is used as an oxidizing agent inorder to oxidize aniline to polyaniline salts via an aqueous polymerization pathway in the presence of protic acids such as sulfuric, nitric, hydrochloric and phosphoric acid. The polymer samples were characterized by infrared, electronic absorption spectral, elemental analysis, conductivity, density and water absorption measurements. The results of the polyaniline salts prepared by pyridinium chlorochromate as an oxidizing agent were compared with that of the polyaniline salt prepared by ammonium persulfate. Generally, aniline is oxidized using ammonium persulfate as an oxidizing agent, which is unstable. In this work, pyridinium chlorochromate is used to oxidize aniline to polyaniline salt and the polymerization reaction could be completed in 30 min. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of high quality inorganic fullerene-like BN hollow spheres via a simple chemical route

High quality inorganic fullerene-like boron nitride hollow spheres (100-200 nm) have been successfully synthesized via a simple chemical route with a 30-40% yield of BN hollow spheres.     

A general chemical route to polyaniline nanofibers

Uniform polyaniline nanofibers readily form using interfacial polymerization without the need for templates or functional dopants. The average diameter of the nanofibers can be tuned from 30 nm using hydrochloric acid to 120 nm using perchloric acid as observed via both scanning and transmission electron microscopy. When camphorsulfonic acid is employed, 50 nm average diameter fibers form. The measured Brunauer-Emmett-Teller surface area of the nanofibers increases as the average diameter decreases. Further characterization including molecular weight, optical spectroscopy, and electrical conductivity are presented. Interfacial polymerization is shown to be readily scalable to produce bulk quantities of nanofibers.     

A simple route to interpenetrating network hydrogel with high mechanical strength

A simple two-step method was introduced to improve the hydrogel mechanical strength by forming an interpenetrating network (IPN). For this purpose, we synthesized polyacrylate/polyacrylate (PAC/PAC), polyacrylate/polyacrylamide (PAC/PAM), polyacrylamide/polyacrylamide (PAM/PAM) and polyacrylamide/poly(vinyl alcohol) (PAM/PVA) IPN hydrogels. The PAC/PAC IPN and PAC/PAM IPN hydrogels showed compressive strength of 70 and 160 kPa, respectively. For the PAM/PAM IPN and PAM/PVA IPN hydrogels, they exhibited excellent tensile strength of 1.2 and 2.8 MPa, and elongations at break of 1750% and 3300%, respectively. A strain relaxation was also observed in the case of PAM series IPN hydrogels. From FTIR, TGA and SEM measurements, we confirmed that physical entanglement, hydrogen bonds and chemical crosslinking played major roles in improving hydrogel strength and toughening. The two-step technique contributes to the understanding of ideal networks, provides a universal strategy for designing high mechanical strength hydrogels, and opening up the biomedical application of hydrogels.     

A general synthetic route to nanofibers of polyaniline derivatives

Nanofibrous mats of a wide variety of polyaniline derivatives can be synthesized without the need for templates or functional dopants by simply introducing an initiator into the reaction mixture of a rapidly mixed reaction between monomer and oxidant.     

A mild, copper catalyzed route to conducting polyaniline

The aniline dimer, N-(4-aminophenyl)aniline has been polymerized cleanly under mild conditions to obtain an emeraldine base form of polyaniline using [MeB(3-(Mes)Pz)3]CuCl as the catalyst and H2O2 as the oxidant, while the subsequent acidification of the emeraldine base gives the conducting emeraldine salt form of polyaniline.     

A simple route to cyclopentane annulation

We have developed a simple method for cyclopentane annulation using inexpensive reagents which is useful for the synthesis of polyquinane systems.     

A simple catalytic route to naproxen

We report herein the asymmetric synthesis of naproxen involving catalytic enantioselective methylation for the first time. The reaction is conducted in a solid–liquid biphasic system using chiral quaternary ammonium salts.     

A simple route to β-aminomethylketones

A simple procedure leading to β-aminomethylketones has been developed. The procedure involves base-catalyzed Michael-type addition of sodium t-butyl acetoacetate to N-Boc imines generated in situ followed by hydrolysis and decarboxylation of the adducts.     

A simple route to micropatterned polymer surfaces

Polymer surfaces with uniform microscale concave arrays were fabricated by spreading polymer solution on the nonsolvent surface, and the concave-patterned surface could further be used as a template to structure convex-patterned polymer surfaces.     

A simple route to chiral phosphinous acid-boranes

We report a simple one-pot synthesis of enantiomerically enriched alkyl- and arylphenylphosphinous acid-borane starting from readily available (R(P))-(-)-menthylhydrogenophenylphosphinate and organolithium reagents.     

A simple synthetic route to substituted cyclopentenolones

Preparation of novel cyclopent-3-ene-1,2-dione dimers from γ-substituted crotonate esters and dimethyl oxalate by vinylogous double Claisen condensations has given access to a series of polyfunctional cyclopentane derivatives potentially useful in synthesis.     

A simple route to nanocrystalline silicon carbide

Nanocrystalline silicon carbide has been prepared via reacting magnesium silicide (Mg₂Si) with carbon tetrachloride (CCl₄) in an autoclave at 450-600°C. X-ray diffraction patterns of the products can be indexed as the cubic cell of SiC with the lattice constant, a=4.352 Å, in good agreement with a=4.349 Å (JCPDS card No. 75-0254). The transmission electron microscopy images show that the sample mainly consists of nanoparticles with an average size from 30 to 80 nm co-existing with a small fraction of nanorods and nanowires. Typically the nanorods range from 20 to 40 nm in diameter and the nanowires have diameters of 20 nm and lengths up to 10 μm. The Raman spectrum shows a characteristic sharp peak at 790 cm⁻¹. X-ray photoelectron spectra (XPS) gives an atomic ratio of Si to C as 1.08:1.00 from the quantification of the peak intensities. Photoluminescence spectrum reveals that the SiC sample emits ultraviolet light of 328 nm. A possible mechanism and the influence of temperature on the formation of crystalline SiC are proposed.     

Regiospecific C-alkylation of uridine: a simple route to 6-alkyluridines

6-Alkyluridines were conveniently synthesized by lithiation and successive alkylation from 2′,3′-O-isopropylideneuridine with complete regioselectivity.     

Benzoyl peroxide oxidation route to polyaniline salts—Part I

Aniline was oxidized to polyaniline salt using benzoyl peroxide as an oxidizing agent in the presence of acids such as sulfuric, nitric, or hydrochloric acid by aqueous polymerization pathway. Polyaniline salts, their corresponding bases and redoped polyaniline salts were characterized by infrared, electronic absorption, x‐ray diffraction spectral techniques, elemental analysis and conductivity measurement. The result of this study indicates that both acid and surfactant group are present in the polyaniline salt as dopants. Polyaniline salts with reasonable yield (around 80%) and conductivity (0.04 S/cm) were prepared. Copyright © 2004 John Wiley & Sons, Ltd.