Suriani Abu Bakar

Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups

Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology.

Controllable Growth of Vertically Aligned Aluminum-Doped Zinc Oxide Nanorod Arrays by Sonicated Sol--Gel Immersion Method depending on Precursor Solution Volumes

Aluminium (Al)-doped zinc-oxide (ZnO) nanorod arrays have been successfully prepared using a novel and low-temperature sonicated sol–gel immersion method. The photoluminescence (PL) spectrum reveals the appearance of two emission peaks from the nanorod that are centred at 381 and 590 nm. The nanorod has a hexagonal structure with a flat-end facet, as observed using field-emission electron microscopy (FESEM). Interestingly, all samples have similar surface morphologies and diameter sizes of 40 to 150 nm after immersion in different precursor-solution volumes. The thickness-measurement results show that the thicknesses of the samples increase after immersion in higher precursor-solution volumes. We show for the first time that the growth of nanorod arrays along the c-axis can be controlled using different precursor volumes, and its growth mechanism is discussed. X-ray diffraction (XRD) spectra indicate that the prepared nanorods are ZnO with a hexagonal wurtzite structure that grows preferentially along the c-axis.

Preparation of multiwall carbon nanotubes (MWCNTs) stabilised by highly branched hydrocarbon surfactants and dispersed in natural rubber latex nanocomposites

The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology.

Synthesis and nucleation-growth mechanism of almost catalyst-free carbon nanotubes grown from Fe-filled sphere-like graphene-shell surface

This finding focuses on the optimization of synthesis time for the transformation of Fe-filled spherical-like graphene shell (GS) to almost catalyst-free carbon nanotube (CNT) structure using two-stage catalytic chemical vapor deposition apparatus. The camphor oil and ferrocene were used as carbon precursor and catalyst respectively, following the variety growth of graphene-family nanomaterials for 2, 4, 6, 8, 10, 30, and 60 min at 800°C synthesis temperature. The graphene-family nanomaterial properties were characterized using field emission scanning electron microscope, high resolution transmission electron microscope, micro-Raman spectrometer, thermogravimetric, and carbon-hydrogen-nitrogen-sulfur/oxygen (CHNS/O) analyzer. The result of field emission scanning electron microscopy analysis reveals that the CNTs were observed with high aspect ratio at 60-min synthesis time. The dependence of integrated intensity ratio of D-band and G-band (ID/IG) presented that ID/IG ratio sharply decreases with longer synthesis time. At higher synthesis time, thermogravimetric and CHNS/O analysis of CNT can obviously improve with decreases of non-carbonaceous material and transition metal catalyst. The nucleation-growth model of Fe-filled spherical-like GS to almost catalyst-free CNT has been highlighted to explain the change in growth mode.

Raman spectroscopic study of carbon nanotubes prepared using Fe/ZnO-palm olein-chemical vapour deposition

Multiwalled carbon nanotubes (MWCNTs) were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD) method at 800-1000°C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein (PO), ferrocene in the presence of 0.05M zinc nitrate, and a p-type silicon wafer were used as carbon source, catalyst precursor, and sample target, respectively. D, G, and G′ bands were observed at 1336-1364, 1559-1680, and 2667-2682 cm-1, respectively. Carbon nanotubes (CNTs) with the highest degree of crystallinity were obtained at around 8000?C, and the smallest diameter of about 2nm was deposited on the silicon substrate at 1000°C.

A Review of Glucose Biosensors Based on Graphene/Metal Oxide Nanomaterials

In recent years, considerable attention has been paid to developing economical yet rapid glucose sensors using graphene and its composites. Recently, the excellent properties of graphene and metal oxide nanoparticles have been combined to provide a new approach for highly sensitive glucose sensors. This review focuses on the development of graphene functionalized with different nanostructured metal oxides (such as copper oxide, zinc oxide, nickel oxide, titanium dioxide, iron oxide, cobalt oxide, and manganese dioxide) for use as glucose biosensors. Additionally, a brief introduction of the electrochemical principles of glucose biosensors (including amperometric, potentiometric, and conductometric) is presented. Finally, the current status and future prospects are outlined for graphene/metal oxide nanomaterials in glucose sensing.

Effect of the ratio of catalyst to carbon source on the growth of vertically aligned carbon nanotubes on nanostructured porous silicon templates

BackgroundThe effect of the ratio of catalyst to carbon source on the growth of vertically aligned carbon nanotubes (VACNTs) has been studied.ResultsDense VACNTs were successfully synthesised on optimised nanostructured porous silicon templates using modified floated carbon source-catalyst in a two-stage hot filament thermal chemical vapour deposition system with different amounts of ferrocene as the catalyst at 800°C. The surface morphologies of the VACNTs were analysed using field emission scanning electron microscopy, and the crystallinity of the nanotubes was observed using micro-Raman spectroscopy.ConclusionsThese data revealed that the amount of catalyst used significantly affected the diameter, crystallinity and growth rate of the synthesised nanotubes. The average diameter of the nanotubes ranged from ≈ 9 to 30 nm with lengths of ≈ 110 μm when 0.5 g ferrocene was used.

Hydrogenated Amorphous Carbon Films

Hydrogenated amorphous carbon (a-C:H) thin film is one of the most studied materials due to its unique features. The a-C:H thin film is a remarkable material because of its novel optical, mechanical and electrical properties and its similarities to diamond. In this chapter we reviewed the structural and optical properties of hydrogenated amorphous carbon (a-C:H) thin films prepared in a DC-PECVD reactor. Both power and ion bombardment energy were continuously changed during the deposition, as a results of varying deposition parameters such as A.B. Suriani Department of Physics, Faculty of Science and Technology, Universiti Pendidikan Sultan Idris, 35900 Tanjung Malim, Perak, Malaysia e-mail: absuriani@yahoo.com A.A. Azira NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia e-mail: azira.aziz@gmail.com Putut Marwoto Physics Department, Faculty of Mathematics and Science, Semarang State University, 50229, Semarang, Indonesia e-mail: pmarwoto@yahoo.com S. Sakrani Physics Department, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia e-mail: samsudi@difz2.fs.utm.my Roslan Md. Nor Department of Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia e-mail: rmdnor@um.edu.my M. Rusop NANO-SciTech Centre, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia e-mail: rusop8@gmail.com Adv Struct Mater, DOI 10.1007/8611_2010_15, # Springer-Verlag Berlin Heidelberg 2010 chamber pressure, electrode distance, CH4 flow rate, and substrate temperature. The films properties ranged from polymer-like to graphite-like a-C:H films, as the power and ion energy increased. The structure and the optical properties of a-C:H films were analyzed by infrared and Raman spectroscopy, UV–Vis Spectrophotometer and photoluminescence. This is to extract the information on sp/sp and hydrogen contents, optical gap, E0 and photoluminescence properties of a-C:H films. The films were found to consist of sp clusters of which the size increases with increasing power and ion bombardment energy during the deposition, resulting in lower hydrogen, sp content, optical gap and photoluminescence response. The increased in hydrogen termination from the films at higher ion energies results in bigger cluster size and produced graphitic films.

The Effect of Precursor Vaporization Temperature on the Growth of Vertically Aligned Carbon Nanotubes Using Palm Oil

Carbon nanotubes (CNTs) were fabricated from palm oil using the thermal chemical vapor deposition technique utilizing a two furnace system. The effect of precursor vaporization temperature of the first furnace, in the range of 300-600°C was systematically studied with the synthesis temperature (second furnace) fixed at 750°C for a total time of 30 min. The samples were characterized using field emission scanning electron microscopy and micro-Raman spectroscopy. CNTs of various packing densities and diameters were synthesized with the varying precursor vaporization temperature. Based on micro-Raman measurements nanotube defect level and the presence of SWCNT were dependent on the vaporization temperature. Vertically aligned CNTs (VACNTs) were found to grow within the vaporization temperature range of 400-500°C, with well graphitized and higher yield obtained at 450°C with excellent lateral alignment, uniform nanotubes diameter (~15 nm), orientation and distribution within the CNT bundles. At vaporization temperatures of 300-350°C and 500-600°C, lower growth rate, bigger nanotubes diameter and higher ID/IG ratio were observed which indicated lower nanotubes quality that produced at both temperature ranges.

Thickness-controlled synthesis of vertically aligned c-axis oriented ZnO nanorod arrays: Effect of growth time via novel dual sonication sol–gel process

Zinc-oxide (ZnO) nanorod arrays were successfully prepared by using dual sonication sol–gel process. Field emission scanning electron microscopy revealed that the nanorods exhibited a hexagonal structure with a flat-end facet. The nanorods displayed similar surface morphologies and grew uniformly on the seed layer substrate, with the average diameter slightly increasing to the range of 65 to 80 nm after being immersed for varying growth times. Interestingly, thickness measurements indicated that the thicknesses of the samples increased as the growth time was extended. In addition, the X-ray diffraction spectra indicated that the prepared ZnO nanorods with a hexagonal wurtzite structure grew preferentially along the c-axis. Therefore, we can conclude that the diameter, length, and orientation of the ZnO nanorod arrays along the c-axis are controllable by adjusting the growth time, motivating us to further explore the growth mechanisms of ZnO nanorods.