Preparation of hemicyanine dye encapsulated silica particles and their application in cotton fabrics

Trans-4- [p- (N, N-Die (2-hydroxyethyl)) styryl] -N- ethyl pyridinium bromide (DHEASPBr-C2), a hemicyanine fluorescent dye, was encapsulated into silica nanoparticles by co-hydrolysis and co-condensation of organosilanes in the presence of the dye. The dye containing silica nanoparticles were applied onto cotton fabrics. Scanning electron microscopy (SEM), UV–vis spectra, single-photon emission fluorescence spectra and reflectance spectra of the samples were characterized. The SEM results showed that the particle size (ranging from 100-200 nm) and dye encapsulating (1.5-8.1 mg dye per g silica matrix) could be adjusted by the concentration of fluorescent dye and organosilanes. The reflectance of the treated cotton fabrics showed that there were obvious adsorption spectra in 410 - 540 nm and emission spectra in 560 - 700 nm.

Preparation of polyacrylonitrile–natural polymer composite precursors for carbon fiber using ionic liquid co solvent solutions

We report on the use of ionic liquid co-solvents in the preparation of polyacrylonitrile–natural polymer carbon fibers as low cost environmentally friendly alternatives to conventional carbon fibers precursors and processing solvents. We have characterized the structure properties of the new composites as a function of dissolving solvent using solid state NMR, DSC, FTIR and TGA. We show that the dissolving solvent plays a significant role in the properties of the new composites, we also find that the incorporation of the natural polymer additive impacts the thermal transition temperatures for the PAN

Single step preparation of meso-porous and reduced graphene oxide by gamma-ray irradiation in gaseous phase

A facile and highly efficient route to produce simultaneously porous and reduced graphene oxide by gamma ray irradiation in hydrogen is here demonstrated. Narrowly distributed nano-scale pores (average size of ∼3 nm and surface density >44,900 pore μm-2) were generated across 10 μm thick graphene oxide bucky-papers at a total irradiation dose of 500 kGy. The graphene oxide sheet reduction was confirmed to occur homogeneously across the structures by Fourier transform infrared spectroscopy and Raman analysis. This one-step, catalyst-free, high penetration and through-put technique, offers great promises potential for the mass production of reduced graphene oxide from cheap graphene oxide. © 2013 Elsevier Ltd. All rights reserved.

Preparation of pH- and salinity-responsive cellulose copolymer in ionic liquid

A novel biodegradable pH- and salinity-responsive cellulose copolymer was prepared by grafting 2-(Dimethylamino) ethylmethacrylate (DMAEMA) onto bagasse cellulose in ionic liquid. The grafting polymerization was achieved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) under microwave irradiation. Copolymers were then characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermo gravimetric analysis measurements. The results revealed that polymer chains had been successfully bonded to the cellulose backbone. Furthermore, the self-assembly of cellulose-g-DMAEMA copolymers at various salt concentrations and pH solution were investigated by means of swelling behavior measurement. It indicated that the copolymers presented dual pH and salinity-responsive properties. The synthetic strategy showed great potential in the modification of other cellulosic biomass to afford new biomaterials with desired properties. © 2014 Springer Science+Business Media Dordrecht.

Preparation of composite electrodes with carbon nanotubes for lithium-ion batteries by low-energy ball milling

Some of the prospective electrode materials for lithium-ion batteries are known to have electronic transport limitations preventing them from being used in the electrodes directly. In many cases, however, these materials may become practical if they are applied in the form of nanocomposites with a carbon component, e.g. via incorporating nanoparticles of the phase of interest into a conducting network of carbon nanotubes. A simple way to prepare oxide-carbon nanotube composites suitable for the electrodes of lithium-ion batteries is presented in this paper. The method is based on low-energy ball milling. An electrochemically active but insulating phase of LiFeTiO4 is used as a test material. It is demonstrated that the LiFeTiO4-carbon nanotube composite is not only capable of having significantly higher capacity (∼105-120 mA h g-1vs. the capacity of ∼65-70 mA h g -1 for the LiFeTiO4 nanoparticles) at a slow current rate but may also operate at reasonably high current rates. © the Partner Organisations 2014.

Preparation of cellulose nanofiber from softwood pulp by ball milling

This paper reports the possibility of producing cellulose nanofiber from softwood pulp using a simple ball milling technique under ambient pressure and at room temperature. The effects of milling conditions including the ball-to-cellulose mass ratio, milling time, ball size and alkaline pretreatment were investigated. It was found that milling-ball size should be carefully selected for producing fibrous morphologies instead of particulates. Milling time and ball-to-cellulose mass ratio were also found important to control the fiber morphology. Alkali pre-treatment helped in weakening hydrogen bonds between cellulose fibrils and removing small particles, but with the risks of damaging the fibrous morphology. In a typical run, cellulose nanofiber with an average diameter of 100 nm was obtained using soft mechanical milling conditions using cerium-doped zirconia balls of 0.4–0.6 mm in diameter within 1.5 h without alkaline pretreatment.

Preparation of size-selective Mn3O4 hexagonal nanoplates with superior electrochemical properties for pseudocapacitors

Porous Mn3O4 hexagonal nanoplates were synthesized through annealing the hydrohausmannite precursor obtained by a one-pot hydrothermal process and by precisely controlling the concentrations of potassium hydroxide and glucose. The effect of potassium hydroxide and glucose on the growth of hexagonal nanoplates was investigated, and a growth mechanism was also proposed. Due to its abundant pores, the pure Mn3O4-based electrode exhibits excellent cycling stability with 100% capacity retention after 5000 cycles. The asymmetric supercapacitor exhibited high performance with an energy density of 17.276 W h kg^-1 at a power density of 207.3 W kg^-1 in a wide potential window of 1.5 V.

Preparation of graphene oxide decorated Fe3O4@SiO2 nanocomposites with superior adsorption capacity and SERS detection for organic dyes

The fast detection and removal of organic dyes from contaminated water has become an urgent environmental issue due to their high toxicity, chemical stability, and low biodegradability. In this paper, we have developed graphene oxide decorated Fe3O4@SiO2 (Fe3O4@SiO2-GO) as a novel adsorbent aiming at the rapid adsorption and trace analysis of organic dyes followed by surface enhanced Raman scattering (SERS). The structure and morphology of the nanocomposites were characterized by transmission electron microscopy (TEM), Fourier infrared spectrometry (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The obtained nanocomposites were used to adsorb methylene blue (MB) in aqueous solution based on π-π stacking interaction and electrostatic attraction between MB and GO, and the adsorption behaviors of MB were investigated. Moreover, the obtained nanocomposites with adsorbed dyes were separated from the solution and loaded with silver nanoparticles for SERS detection. These nanocomposites showed superior SERS sensitivity and the lowest detectable concentration was 1.0 × 10-7 M.

Preparation of monodisperse aqueous microspheres containing high concentration of L-ascorbic acid by microchannel emulsification

Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10 mL h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25 kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16 µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15 kPa.

Well-controlled preparation of evenly distributed nanoporous HOPG surface via diazonium salt assisted electrochemical etching process

Evenly distributed nanoporous highly oriented pyrolytic graphite (HOPG) surfaces with controllable pore size were successfully prepared via diazonium salt assisted electrochemical etching method. The porous HOPG was investigated by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) Raman spectroscopy and X-ray diffraction. The size of these pores can be tuned by manipulating the electrochemical etching time. These porous HOPG substrates also demonstrated the enhanced electrocatalytical behaviour and were employed as benign arena for the immobilization of Ru(bpy)32+ for electrochemiluminescence (ECL) sensing applications.

One-step preparation of graphene nanosheets via ball milling of graphite and the application in lithium-ion batteries

An improved method for mass production of good-quality graphene nanosheets (GNs) via ball milling pristine graphite with dry ice is presented. We also report the enhanced performance of these GNs as working electrode in lithium-ion batteries (LIBs). In this improved method, the decrease of necessary ball milling time from 48 to 24 h and the increase of Brunauer–Emmett–Teller surface area from 389.4 to 490 m2/g might be resulted from the proper mixing of stainless steel balls with different diameters and the optimization of agitation speed. The as-prepared GNs are investigated in detail using a number of techniques, such as scanning electron microscope, atomic force microscope, high-resolution transmission electron microscopy, selected area electron diffraction, X-ray diffractometer, and Fourier transform infrared spectroscopic. To demonstrate the potential applications of these GNs, the performances of the LIBs with pure Fe3O4 electrode and Fe3O4/graphene (Fe3O4/G) composite electrode were carefully evaluated. Compared to Fe3O4-LIBs, Fe3O4/G-LIBs exhibited prominently enhanced performance and a reversible specific capacity of 900 mAh g−1 after 5 cycles at 100 and 490 mAh g−1 after 5 cycles at 800 mA g−1. The improved cyclic stability and enhanced rate capability were also obtained.