Room-temperature growth of carbon nanofibers on plastic substrates

A very simple method to synthesize densely distributed carbon nanofibers (CNFs) on flexible plastic substrates at room temperature with no catalyst is demonstrated. Carbon film was deposited onto polyimide, poly-ethylene-terephthalate (PET) films, Si plates and a Ni mesh, which were then sputtered with obliquely incident Ar⁺ ions at 3 keV at room temperature. Linear-shaped CNFs oriented in the incidence direction of the ion beam grew on the sputtered substrates, as confirmed by scanning (SEM) and transmission electron microscopes (TEM). CNF growth on a PET substrate, which is a non-heat-tolerant plastic, has never been reported so far. CNFs thus grown were characterized as amorphous without a hollow structure. The diameter of CNFs was almost identical (20-30 nm) despite a large difference in CNF length (0.1-4 μm). In addition, the CNF-tipped cones were demonstrated to act successfully as a template to fabricate one dimensional (1-D) zinc oxide (ZnO) nanostructures on a PET substrate. Thus, it was believed that the ion-irradiation technique would open up a new approach to fabricate any kinds of 1-D nanomaterials on flexible substrates at room temperature.     

Cyclic Voltammetrically‐Prepared MnO2 Coated on an ITO Glass Substrate

For the first time, nanostructured manganese dioxide was successfully electrodeposited onto an ITO (indium tin oxide) glass substrate by cyclic voltammetry (CV) method from an aqueous solution of 0.1 M Na₂SO₄ containing 5 × 10⁻³ M MnSO₄. The obtained manganese dioxide‐modified ITO glass substrates were characterized by energy dispersive spectrometry (EDS), Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM), respectively. All results not only proved the existence of MnO₂ on an ITO glass substrate but also demonstrated that the morphology of the obtained MnO₂ was greatly affected by the electrodeposition conditions. Also, this MnO₂‐modified ITO electrode was systematically investigated by cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS) in an aqueous electrolyte of 0.1 M Na₂SO₄. The results obtained from electrochemical measurement indicated that this developed MnO₂‐modified ITO electrode has a satisfied specific capacitance value of 264 F·g⁻¹ and exhibits excellent electrochemical stability and reversibility.     

Deposition of superhydrophobic nanostructured Teflon-like coating using expanding plasma arc

A novel approach was used to grow nanostructured Teflon-like superhydrophobic coatings on stainless steel (SS). In this method Teflon tailings were pyrolyzed to generate fluorocarbon precursor molecules, and an expanding plasma arc (EPA) was used to polymerize these precursors to deposit Teflon-like coating. The coating shows super hydrophobic behavior with water contact angle (WCA) of 165°. The coating was observed to be uniform. It consists of nanostructured (∼80-200 nm) features, which were confirmed by scanning electron microscopy. The chemical bond state of the film was determined by XPS and FTIR, which indicate the dominance of -CF₂ groups in the deposited coating. The combination of nanofeature induced surface roughness and the low surface energy imparted by Teflon-like coating is responsible for the observed superhydrophobic nature.     

Synthesis and surface characteristics of CeTbO3+δ induced by femtosecond laser irradiation

This work describes the use of focused, high-intensity light from a Ti:sapphire laser that generates femtosecond pulses to irradiate mixture of CeO₂ and Tb₄O₇ under ambient conditions. The prepared samples were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). XRD and XPS measurement results demonstrated that solid solution CeTbO_3+δ with cubic fluorite structure has been synthesized on the irradiated target surface. SEM micrographs showed that the ultra-short laser irradiation resulted in the formation of foamy structure and spherical particles with size varying from about 30 to 200 nm. The formation mechanism has been discussed in detail.     

Reverse microemulsion-directed synthesis of hydroxyapatite nanoparticles under hydrothermal conditions

Morphology controllable hydroxyapatite (HA) nanoparticles were synthesized using reverse microemulsion (aqueous solution/TX-100/n-butanol/cyclohexane) systems under hydrothermal conditions. The concentration of cetyltrimethylammonium bromide (CTAB) contained in the aqueous solution and pH value had significant effect on the morphology and crystal phases of the final products. All the as-synthesized HA nanoparticles had a larger a value but smaller c value compared with the standard values of the JCPDs card. The existence of CTAB could be attributed to the growth of HA along an axis, but inhibit the growth along the c-axis to some extent. A proposed model was established to explain the change of the lattice parameters.     

Synthesis and characterization of nanostructure hydrous iron–titanium binary mixed oxide for arsenic sorption

Synthesis of nanostructure hydrous iron–titanium binary mixed oxide (NHITBMO) had been reported by a simple method, and characterized by the X-ray diffraction (XRD), thermal analysis, transmission electron microscope (TEM), Föurier Transform Infrared (FTIR), surface area, and zero surface charge pH (pHzpc). The synthetic oxide was hydrated and microcrystalline with 77.8 m² g^?1 BET surface area. The particle size (nm) calculated using XRD peak table and TEM image was ~10–13 and 6–8, respectively. The pH_zpc value was 6.0 (±0.05) for the oxide. The NHITBMO showed pH dependent good sorption affinity for arsenic from the aqueous solution and, the Langmuir monolayer capacity (mg g^?1) was 80.0 and 14.6, respectively, for the As(III) and As(V). The pseudo-second order equation described the room temperature arsenic sorption kinetic data well. The minimum dose required was 1.6 g NHITBMO per L of water (As_total = 0.24 mg L^?1) to reduce the arsenic level below 0.01 mg L^?1 in batch treatment process.     

Correlation of photoluminescence of (La,Ln) PO<Subscript>4</Subscript>:Eu<Superscript>3+</Superscript> (Ln = Gd and Y) phosphors with their crystal structures

Eu³⁺-doped (La, Ln) PO₄ (Ln = Gd and Y) phosphors were prepared by a facile co-precipitation method. Their structures and luminescent properties under UV excitation were investigated. Structural characterization of the nanostructured luminescence material was carried out with X-ray powder diffraction analysis. Scanning electron microscopy was carried out to understand the surface morphological features and grain sizes with 50–100 nm. It is found that (La, Gd) PO₄:Eu³⁺ phosphors have the same crystal structure as LaPO₄:Eu³⁺, which is monoclinic with a little different lattice parameters. In the case of (La, Y) PO₄:Eu³⁺ phosphors, however, the gradual change from monoclinic to tetragonal structure of host lattice was observed, as the amount of Y ion increased. From the photoluminescence spectra for (La, Ln) PO₄:Eu³⁺ (Ln = Gd and Y), the emission transition ⁵D₀ → ⁷F₁ has been found to be more prominent over the normal red emission transition ⁵D₀ → ⁷F₂. Furthermore, the size influence on the products was discussed. It was observed that the spectral features possess sharp and bright emission for potential applications on the monitors of the television and some other related electronic systems, in observing the images in orange–red color.     

A “ladder” Morphology in an ABC Triblock Copolymer

ABC triblock copolymers are known to exhibit a wide variety of unique types of morphologies compared to AB diblock copolymers. In the present study, poly(styrene-block-(ethylene-alt-propylene)-block-(methyl methacrylate)) (SEPM) triblock copolymers were synthesized and their morphologies were extensively studied by transmission electron microtomography (TEMT). In the SEPM triblock copolymer, two kinds of morphologies coexist: One was the well-known knitting morphology, and the other was a novel morphology called the “ladder morphology”. The ladder morphology was a major morphology in the SEPM copolymer, the stability of which was discussed in terms of the interfacial area and the solubility parameters between the three components.     

Fabrication and surface-enhanced Raman scattering (SERS) of Ag/Au bimetallic films on Si substrates

Ag films on Si substrates were fabricated by immersion plating and served as sacrificial materials for preparation of Ag/Au bimetallic films by galvanic replacement reaction. The formation procedure of films on the surface of Si was studied by scanning electron microscopy (SEM), which revealed Ag films with island and dendritic morphologies experienced novel structural evolution process during galvanic replacement reaction, and nanostructures with holes were produced within the resultant Ag/Au bimetallic films. SERS activity both of sacrificial Ag films and resultant Ag/Au bimetallic films was investigated by using crystal violet as an analyte. It has been shown that SERS signals increased with the process of galvanic substitution and reached intensity significantly stronger than that obtained from pure Ag films.     

The orientation of the self-assembled monolayer stripes on a crystalline substrate

Two-phase monolayers adsorbed on crystalline substrates can form many patterns. After reviewing the experimentally observed patterns on various substrates, we extend a thermodynamic theory to account for the anisotropy in surface stress, substrate stiffness, and phase boundary energy. We solve the elastic field in the anisotropic substrate by using the Stroh formalism. We then focus on the pattern of periodic stripes, and determine the orientation of the stripes that minimizes the free energy. As an example, we examine in detail the (110) surface of a cubic crystal. Depending on the parameters that characterize anisotropy, the stripes can orient along either , or [001], or certain directions off the two crystalline axes. The transition between these orientations can be of either first or second order. The predications point to additional experiments that are needed to further the understanding.