Facile one‐step synthesis of electromagnetic functionalized polypyrrole/Fe3O4 nanotubes via a self‐assembly process

This article reports a simple self‐assembly process for facile one‐step synthesis of novel electromagnetic functionalized polypyrrole (PPy)/Fe₃O₄ composite nanotubes using p‐toluenesulfonic acid (p‐TSA) as the dopant and FeCl₃ as the oxidant. The key trick of the present method is to use FeCl₃ as the oxidant for both PPy and Fe₃O₄ in the same time to synthesize PPy/Fe₃O₄ composite nanotubes in one‐step. This facile one‐step method is much simpler than the conventional approach using the Fe₃O₄ nanoparticles as the additives. Compared to the similar composites synthesized using the conventional method, the as‐prepared PPy‐p‐TSA/Fe₃O₄ composite nanotubes using the facile one‐step self‐assembly process show much higher room‐temperature conductivity. Moreover, the composite nanotubes display interesting ferromagnetic behavior. The electrical properties of the PPy‐p‐TSA/Fe₃O₄ composite nanotubes are dominated by the amount of FeCl₃ while their magnetic properties are controlled by the amount of FeCl₂. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 320–326, 2010     

Heparin‐Controlled Growth of Polypyrrole Nanowires

Summary: Heparin, a potent anticoagulant, has been used for the first time for the synthesis of PPy nanowires serving not only as an anion dopant but also as an effective morphology‐directing agent. The obtained PPy nanowires exhibit long and fine structures with smooth surface and the average diameter of the nanowires is about 90–100 nm and lengths are several hundred nanometers to micrometers. The possible formation mechanism of PPy nanowires may be related to the chain structure of heparin with functional groups ( SO and  COO⁻) on the surface. The effect of concentrations of pyrrole monomers and heparin on the morphology and size of PPy nanowires has been investigated.

SEM image of PPy nanowires synthesized in the presence of heparin.     

Reactive Template Synthesis of Polypyrrole Nanotubes for Fabricating Metal/Conducting Polymer Nanocomposites

Unique nanocomposites of polypyrrole/Au and polypyrrole/Pt hybrid nanotubes are synthesized employing polypyrrole (PPy) nanotubes as an advanced support by solution reduction. The conducting polymer PPy nanotubes are fabricated by using pre‐prepared MnO₂ nanowires as the reactive templates. MnO₂ nanowires induce the 1D polymerization of pyrrole monomers and the simultaneous dissolution of the templates affords the hollow tube‐like structure. The loading content of metal nanoparticles in the nanocomposites could be adjusted by simply changing the amount of metal precursors. This work provides an efficient approach to fabricate an important kind of metal/conducting polymer hybrid nanotubes that are potentially useful for electrocatalyst and sensor materials.     

Decorating Polypyrrole Nanotubes with Au Nanoparticles by an In Situ Reduction Process

Au nanoparticle‐decorated polypyrrole nanotubes (defined as PPy/Au nanocomposites) are prepared by an in situ reduction process. Polypyrrole (PPy) nanotubes are prepared by a self‐degraded template method, and Au nanoparticles are deposited in situ by the reduction of HAuCl₄. The size and uniformity of the Au nanoparticles that decorate the PPy nanotubes can be controlled by adjusting the experimental conditions, such as the stabilizers used and the reaction temperature. The morphologies and optical properties of the nanocomposites have been characterized by scanning electron microscopy, transmission electron microscopy, UV‐vis, and FT‐IR spectroscopy. Conductivity measurements show that the conductivities of the nanocomposites decrease with a decrease of temperature, and the conductivity–temperature relationship obeys the quasi‐one dimensional variable range hopping model.

     

Insertion of Polypyrrole Chains into Montmorillonite Galleries by a Solvent‐Free Mechanochemical Route

Summary: Non‐ionic pyrrole was directly intercalated into unmodified montmorillonite (MMT) and organically modified MMT galleries by adsorption, and subsequently polymerized within the interlamellar spaces by a mechanochemical route under solvent‐free conditions. XRD analysis revealed the successful intercalation of pyrrole into unmodified MMT and organically modified MMT clay galleries by mechanochemical grinding. After in situ polymerization, the XRD and FT‐IR analyses confirmed the insertion of polypyrrole chains between both MMT galleries.

X‐ray powder diffraction patterns of (A) pyrrole‐intercalated MMT and (B) pyrrole‐intercalated C18‐MMT.     

Water‐Soluble Methyl Orange Fibrils as Versatile Templates for the Fabrication of Conducting Polymer Microtubules

One‐dimensional methyl orange fibrils can be easily prepared. They are stable in acidic aqueous solutions and soluble in neutral water. When used to synthesize conducting polymer microtubules, the fibrils act as “hard templates” formally but as “soft templates” effectively. Microtubular structures of polypyrrole, polyaniline, and poly(3,4‐ethylenedioxythiophene) have been achieved successfully via such water‐soluble versatile templates.

     

Fabrication of Electrically Conducting Polypyrrole‐Poly(ethylene oxide) Composite Nanofibers

Summary: Electrically conducting polypyrrole‐poly(ethylene oxide) (PPy‐PEO) composite nanofibers are fabricated via a two‐step process. First, FeCl₃‐containing PEO nanofibers are produced by electrospinning. Second, the PEO‐FeCl₃ electrospun fibers are exposed to pyrrole vapor for the synthesis of polypyrrole. The vapor phase polymerization occurs through the diffusion of pyrrole monomer into the nanofibers. The collected non‐woven fiber mat is composed of 96 ± 30 nm diameter PPy‐PEO nanofibers. FT‐IR, XPS, and conductivity measurements confirm polypyrrole synthesis in the nanofiber.

An SEM image of the PPy‐PEO composite nanofibers. The scale bar in the image is 500 nm.     

Facile Synthesis of Self‐Assembled Polyaniline Nanodisks

Polyaniline nanodisks have been synthesized successfully by the chemical oxidation polymerization of aniline by a self‐assembly process without the use of any acid. The thickness and lateral dimensions of the polyaniline nanodisks are in the range of 20–30 nm and 1–2 µm, respectively. The influence of synthetic parameters, such as the concentration of ammonium peroxydisulfate and pH, on the morphologies of polyaniline nanostructures have been investigated.

     

Design of New Reaction Fields for Spherical Polypyrrole Particle Synthesis

Summary: Polypyrrole conducting polymers have been investigated widely for various applications because of their thermal and environmental stability and good electrical conductivity. Using chemical oxidative polymerization for the synthesis of polypyrrole particles, the reaction rate is very fast. In this study, we designed two new reaction fields for the synthesis of spherical polypyrrole nanoparticles. In the first system, oxidative polymerization of monomer droplets infused in a water/oil (W/O) emulsion reaction field was investigated. The second system employed dispersed monomer in an aqueous solution with a low concentration of oxidant in which polymerization was augmented by ultrasonic irradiation. Effective control of the reaction rate was important for enabling the synthesis of fine spherical polypyrrole particles.     

Taurine‐Induced Fabrication of Nano‐Architectured Conducting Polypyrrole on Biomedical Titanium

In this article, taurine, one of the small biomolecules associated with bone metabolism, is firstly utilized to induce the fabrication of nano‐architectured conducting polypyrrole (NCPPy) on biomedical titanium in diverse pH values of phosphate buffer solution (PBS). Accordingly, the possible mechanism for the fabrication of NCPPy is proposed, which is dependent on the states of polytaurine from the polymerization of taurine, i.e., the inability of forming polytaurine and unordered restricted space results in taurine‐incorporated and polytaurine‐incorporated tightly packed nanoparticles (pH 6.2 and 8.0), respectively, and however, ordered restricted space constructed by polytaurine chains induces the fabrication of polytaurine‐incorporated nanopillars (pH 6.8) and polytaurine‐incorporated nanowire networks (pH 7.4).

     

Formation of Supramolecular Nanotubes by Self‐assembly of a Phosphate‐linked Dimeric Anthracene in Water

The assembly of supramolecular polymers from a phosphodiester‐linked dimeric anthracene is described. AFM and TEM imaging reveals that the supramolecular polymers self‐assemble into nanotubes in water. Subsequent photodimerization experiments indicate that the supramolecular polymerization occurs via end‐to‐end stacking rather than an interdigitation arrangement of the building blocks.     

Template Synthesis of Linear‐Chain Nanodiamonds Inside Carbon Nanotubes from Bridgehead‐Halogenated Diamantane Precursors

A simple method for the synthesis of linear‐chain diamond‐like nanomaterials, so‐called diamantane polymers, is described. This synthetic approach is primarily based on a template reaction of dihalogen‐substituted diamantane precursors in the hollow cavities of carbon nanotubes. Under high vacuum and in the presence of Fe nanocatalyst particles, the dehalogenated radical intermediates spontaneously form linear polymer chains within the carbon nanotubes. Transmission electron microscopy reveals the formation of well‐aligned linear polymers. We expect that the present template‐based approach will enable the synthesis of a diverse range of linear‐chain polymers by choosing various precursor molecules. The present technique may offer a new strategy for the design and synthesis of one‐dimensional nanomaterials.     

Facile one‐pot synthesis and characterization of novel nanostructured organic dispersible polyaniline

Novel polyaniline (PANI) with nanotube, nanosheet, and nanofiber shapes was facilely synthesized by a self‐templating one‐pot process. Anilinium‐dodecylsulfate (DS) complex, obtained by mixing equivalent amounts of aniline and sodium dodecylsulfate (SDS), played a template‐like role in forming PANI nanostructures. It was found that the morphology and electrical conductivity of the PANI nanostructures changed with the amount of SDS and the reaction temperature. Nanotube‐shaped PANI synthesized at the temperature of anilinium‐DS complex formation in presence of SDS (concentration <0.12 M) showed high conductivity (12.9 S/cm). At higher temperature, the morphology changed to shape of a rose flower and electrical conductivity decreased to 3.95 S/cm. This suggested that both temperature and SDS concentration were key parameters for controlling the formation of the anilinium‐DS complex that acted as a template. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1024–1029, 2009     

Polypyrrole Nanotubes Conjugated with Human Olfactory Receptors: High‐Performance Transducers for FET‐Type Bioelectronic Noses

Get a whiff of this : Human olfactory receptor (hOR)‐conjugated polypyrrole (PPy) nanotubes were integrated into the field‐effect transistor (FET) sensor platform for the fabrication of high‐performance bioelectronic noses (see picture, S=source, D=drain). The device can translate and amplify hOR–odorant interaction into a detectable signal, and it showed highly sensitive and specific responses toward a target odorant.

     

溶胶-凝胶模板法制备钛酸钡纳米管

采用氢氧化钡和钛酸四丁酯为前驱体, 溶胶-凝胶结合模板法制备了钛酸钡纳米管, 通过SEM, TEM, XPS和XRD等表征分析, 钛酸钡纳米管直径100 nm, 钛酸钡为立方相结构, 晶胞参数a＝3.995 Å.     

Facile Synthesis of Polyaniline‐Polypyrrole Nanofibers for Application in Chemical Deposition of Metal Nanoparticles

Polyaniline‐polypyrrole (PANI‐PPy) nanofibers with high aspect ratios have been synthesized by a one‐step, surfactant‐assisted chemical oxidative polymerization from mixtures of aniline (An) and pyrrole (Py) monomers. PANI‐PPy nanofibers synthesized with an excess of either PANI or PPy show similar spectral (UV‐vis and FT‐IR) characteristics as the individual homopolymers, whereas nanofibers from an equimolar mixture of An and Py display unique spectral characteristics. PANI‐PPy nanofibers undergo a spontaneous redox reaction with metal ions to produce metal nanoparticles with various morphologies and/or sizes. These findings may open new opportunities for synthesizing functional polymer nanofibers and metal nanoparticles with controllable sizes and/or morphologies.

     

Design of free‐standing microstructured conducting polymer films for enhanced particle removal from non‐uniform surfaces

Efficient removal of particles from topologically‐complex surfaces is of significant import for a range of applications (e.g., explosive residue removal in security arenas). Here, we synthesize next‐generation polymeric particle removal swabs with tuned structural features to elucidate the influence of the polymer microstructure on the removal of trace particles from surfaces. Specifically, microstructured free‐standing films of the conducting polymer polypyrrole (PPy) were synthesized through template‐assisted electropolymerization techniques. The removal of polystyrene microspheres from representative aluminum surfaces of varying roughness was evaluated as a function of the PPy microstructure. PPy‐based microstructured swabs displayed increased particle trapping properties relative to non‐textured PPy‐based swabs and current commercial swabs. This increased effectiveness occurred from the more intimate particle‐swab contact, leading to increased van der Waals interactions for the microstructured swabs. Therefore, this effort provides critical design rules for the production of microstructured conducting polymer materials for their application toward advanced particle removal technologies. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1968–1974     

Fabrication of a Metal Particle Array Based on a Self‐Assembled Template from a Two‐Armed Polymer

A two‐armed polymer with a crown ether core self‐assembles to produce macroporous films with pores perpendicularly reaching through the film down to the substrate. A possible assembling mechanism is discussed. The pore size can be conveniently adjusted by changing the solution concentration. These through‐hole macroporous films provide a template for fabricating an array of Cu nanoparticle aggregates.