Zhitao Wang | Curtin University (original) (raw)

Papers by Zhitao Wang

Polymer Preprints, Jan 1, 2003

Polymer fibers have found uses in several important fields of research and technology depending o... more Polymer fibers have found uses in several important fields of research and technology depending on the type of polymer and the diameter of the fiber used. These applications range from the manufacture of fabric material 1 to more complex nanoelectronic devices based on conducting polymers 2,3 . One of the most important features inherent to fibers is the large surface area which can be exploited in specific applications for example in sensors 4 , catalysts 5 and electromagnetic shielding 6 among others. Although discovered in the 1930's 7 , electrospinning is increasingly becoming very popular in the preparation of polymer fibers either in the form of individual fibers or nonwoven fiber mats. Using this very simple technique, it is now possible to spin polymer fibers (both conducting and nonconducting) under ambient conditions with diameters ranging from several micrometers to as small as a few nanometers . While the conductivity of non-conducting and conducting polymer nanofibers is far below that of conventional metals, one can overcome this drawback by depositing metals on individual fibers using the electroless deposition technique 6,16 . The advantage of this technique is that it is non-destructive and one can have the fibers uniformly coated with metals to yield highly conducting substrates. Unlike conventional metal evaporation, electroless deposition covers the entire fiber with the metal, not just that portion of the fiber in the direct line of sight path from an evaporation source.

Journal of Textile Research, Jan 1, 2008

Abstract Electrospinning method was used to fabricate PVA and PAN nanofibers. The effect of solut... more Abstract Electrospinning method was used to fabricate PVA and PAN nanofibers. The effect of solution mass concentration and conductivity on electrospun fiber morphology was investigated by scanning electron microscopy* SEM2. The result showed that the beads ...

Journal of Materials Processing Technology, Jan 1, 2010

Polyacrylonitrile (PAN)-based carbon nanofiber supported Fe/Co/Ni ternary alloy nanoparticles wer... more Polyacrylonitrile (PAN)-based carbon nanofiber supported Fe/Co/Ni ternary alloy nanoparticles were prepared by using the electrospinning technique for potential fuel cell applications. The solution was prepared by adding pre-solved catalytic precursor into PAN/DMF solution. The effect of PAN and catalyst precursor concentration on solution properties (viscosity and conductivity) and heat stabilization temperature has been investigated. Electrospun nanofibers were characterized by field emission scanning electron microscope, transmission electron microscope, energy dispersive spectrometer and X-ray diffractometer. It has been found that ternary nanoparticle size is in the range of 5–115 nm (average: 20 nm) and is a crystal alloy of Fe, Co and Ni. Also, TEM results demonstrate that in some regions metal nanoparticles tend to agglomerate into larger particles mainly due to the non-uniform distribution of nanoparticles in as-spun condition. PAN-derived carbon nanofiber mean diameter was measured as 200 nm by varying from 40 nm to 420 nm.

Chemistry-A European …, Jan 1, 2009

... PAN (10 wt %) were dissolved in DMF at 60 °C with mechanical stirring for at least 72 h. Thee... more ... PAN (10 wt %) were dissolved in DMF at 60 °C with mechanical stirring for at least 72 h. Theelectrospinning of the precursor nanofibers was carried by using a 0.5 mL h −1 flow rate, 15 cm needle-to-collector distance, and 12.5 kV applied voltage. The electrospun [Ni(OAc) 2 ...

Journal of Wuhan University of Technology-materials Science Edition, Jan 1, 2011

One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks f... more One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems. In this work, the composite Ni 0.5 Zn 0.5 Fe 2 O 4 (NZFO)/ Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) nanofi bers with average diameters about 65 nm are prepared by electrospinning from poly(vinyl pyrrolidone) (PVP) and metal salts. The precursor composite NZFO/PZT/PVP nanofi bers and the subsequent calcined NZFO/PZT nanofi bers are investigated by Fourier transform infrared spectroscopy (FT-IR) , X-ray diffraction (XRD), scanning electron microscopy (SEM).The magnetic properties for nanofi bers are measured by vibrating sample magnetometer(VSM). The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases, which are constructed from about 37 nm NZFO and 17 nm PZT grains. The saturation magnetization of these NZFO/PZT nanofi bers increases with increasing calcination temperature and contents of NZFO in the composite.

Thin Solid Films, Jan 1, 2008

... 7(b) and (c) indicated that hydrogen impurities were incorporated inadvertently into the fibe... more ... 7(b) and (c) indicated that hydrogen impurities were incorporated inadvertently into the fibers during the processing probably due to the use of PVA. The FT-IR results are in good agreement with the hydrogen incorporated results (ZnO/0.8at.% Al) reported by Sagar et al. [24]. ...

Solid State Ionics, Jan 1, 2010

The nanostructured Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers for use as lithium ion batteries... more The nanostructured Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers for use as lithium ion batteries were prepared by co-electrospinning combined with a sol–gel method. The core–shell Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers show diameter of less than 5 μm and shell thickness of ca.300 nm, which are composed of the randomly arranged nanoparticles with size of 20–50 nm. The charge–discharge curves and cycle performance analyses indicated that the core–shell Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers possess a high charge–discharge capacity, as well as good cyclical stability.

Journal of Applied Polymer Science, Jan 1, 2007

Electrospinning is a relatively simple method to produce submicron fibers from solutions of diffe... more Electrospinning is a relatively simple method to produce submicron fibers from solutions of different polymers and polymer blends. If the solution is absolutely insulating, or the applied voltage is not high enough that electrostatic force cannot overcome the surface tension, then no fiber can be produced by electrospinning; however, if some salt is added in the solution, the problem can be overcome. The effect of different salts on electrospinning of polyacrlonitrile (PAN) polymer solution was investigated in this article. The various inorganic salts used in this work include LiCl, NaNO3, NaCl, and CaCl2.The results show that when the salts were added, respectively, into different concentrations of PAN solution, the order of conductant was LiCl > NaNO3 > CaCl2 > NaCl > no salt added. Viscosity and shearing strength of electrospinning solutions are slightly affected by the adding of salts and mainly affected by the changes in concentration of PAN electrospinning solutions. The diameter of nanofibers electrospun by solutions with different salts size down as follows: LiCl > NaNO3 > CaCl2 > NaCl. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3865–3870, 2007

Biosensors & Bioelectronics, Jan 1, 2009

A novel nonenzymatic glucose sensor was developed based on the renewable Ni nanoparticle-loaded c... more A novel nonenzymatic glucose sensor was developed based on the renewable Ni nanoparticle-loaded carbon nanofiber paste (NiCFP) electrode. The NiCF nanocomposite was prepared by combination of electrospinning technique with thermal treatment method. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that large amounts of spherical nanoparticles were well dispersed on the surface or embedded in the carbon nanofibers. And the nanoparticles were composed of Ni and NiO, as revealed by energy dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD). In application to nonenzymatic glucose determination, the renewable NiCFP electrodes, which were constructed by simply mixing the electrospun nanocomposite with mineral oil, exhibited strong and fast amperometric response without being poisoned by chloride ions. Low detection limit of 1 μM with wide linear range from 2 μM to 2.5 mM (R = 0.9997) could be obtained. The current response of the proposed glucose sensor was highly sensitive and stable, attributing to the electrocatalytic performance of the firmly embedded Ni nanoparticles as well as the chemical inertness of the carbon-based electrode. The good analytical performance, low cost and straightforward preparation method made this novel electrode material promising for the development of effective glucose sensor.

Studies in Surface Science and Catalysis, Jan 1, 2010

The Ni/SiO2 fiber catalysts is successfully prepared for the first time by sol-gel and electrospi... more The Ni/SiO2 fiber catalysts is successfully prepared for the first time by sol-gel and electrospinning techniques and used as a reforming catalyst. Nickel acetate and tetraethyl orthosilicate are used as a source of nickel and silica at different Ni loading (5, 10, and 20%wt). The effect of spinning voltage on the morphology of the SiO2 fiber is studied. The Ni/SiO2 fiber catalyst is prepared by impregnation technique and characterized by SEM-EDS, XRD, and TPR. SEM results show that the average diameter of the SiO2 fibers ranged from 1.28 μm to 930 nm. The amount of Ni metal measured by EDS technique is close to that of Ni loading. The reaction test shows that the activity of the fiber catalyst is higher than that of a conventional Ni/SiO2 porous catalyst, and the synthesis gas with H2/CO ratio of 2, a raw material for Fischer-Tropsch synthesis, is obtained by using the fiber catalyst.