| Current
Nanoscience
ISSN: 1573-4137
Current Nanoscience
Volume 3, Number 3, August 2007
Contents
Shape-Controlled Synthesis of Gold Nanoparticles Under
UV Irradiation in the Presence of Poly(Ethylene Glycol) Pp.
195-198
Xuzhong Luo and Toyoko Imae
[Abstract]
On Combustion Generated Nanoparticles and their Biological
Effects. Part I: Measurement of Nanoparticles and their Detection
in and Behind Flames Pp. 199-205
H.-H. Grotheer, H. Pokorny, J. Happold, T. Gonzalez Baquet,
M. Thierley, M. Aigner, C. Baumstark-Khan, C.E. Hellweg and
A. Arenz
[Abstract]
Polymer/Metal Nanocomposites: Assembly of Metal
Nanoparticles in Polymer Films and their Applications
Pp. 206-214
Shin Horiuchi and Yukimichi Nakao
[Abstract]
Deposition of Ru-Ni-S Nanoparticles on Carbon by
Spray-Pyrolysis: Effects of Solvent and other Processing Parameters
Pp. 215-221
Kalyana C. Pingali, Shuguang Deng and David A. Rockstraw
[Abstract]
Direct Coating of Particles by a Liquid Phase Process
Pp. 222-240
Yoshio Kobayashi, Shunchao Gu, Daisuke Nagao and Mikio
Konno
[Abstract]
Comparative Study of the Required Force for Performing
Equal Channel Angular Extrusion with Routes A and C
Pp. 241-244
J. León, C. J. Luis, R. Luri, B. Huarte and I.
Puertas
[Abstract]
Dendritic Functionalization of Metal Nanoparticles
for Nanoparticle-Cored Dendrimers
Pp. 245-254
Young-Seok Shon and Daeock Choi
[Abstract]
Preparation and Characterization of Free-Standing
Cyclotrimethylenetrinitramine (RDX) Films with a Gelatin as
Matrix Pp. 255-258
Qing-Ping Luo, Chong-Hua Pei, Fu-De Nie, Zhao-Qian Li,
Guang-Cheng Yang and Hui Huang
[Abstract]
Adsorption of Sodium Oleate on Nano-sized Fe3O4
Particles Prepared by Co-precipitation Pp. 259-263
Xingping Zhou, Siyu Ni, Xiaqin Wang and Fan Wu
[Abstract]
Micromorphology of the Yellow Cuticle in Social
Wasps: The Presence of Rhabdomeric and Ciliary Peripheral
Photoreceptors Pp. 264-272
Jacob S. Ishay, Marian Plotkin, Reuben Hiller, Stanislav
Volynchik and David J. Bergman
[Abstract]
Abstracts
[Back to top]
Shape-Controlled Synthesis of Gold Nanoparticles
Under UV Irradiation in the Presence of Poly(Ethylene Glycol)
Xuzhong Luo and Toyoko Imae
Dendritic gold nanoparticles and triangular gold plates were
synthesized via a simple photochemical reduction protocol.
The shape of nanoparticles depended on the concentration of
poly(ethylene glycol), which was used on the preparation in
an aqueous solution. On the other hand, the size of nanoparticles
was controlled by the duration of UV irradiation. The mechanism
of morphology variation was discussed.
[Back to top]
On Combustion Generated Nanoparticles and their Biological
Effects. Part I: Measurement of Nanoparticles and their Detection
in and Behind Flames
H.-H. Grotheer, H. Pokorny, J. Happold, T. Gonzalez Baquet,
M. Thierley, M. Aigner, C. Baumstark-Khan, C.E. Hellweg and
A. Arenz
This series aims at the measurement of flame generated nanoparticles
and an assessment of their biological effects. In the present
part a brief review is given on previous papers dealing with
nanoparticles with emphasis on detection through various methods.
A more detailed account is provided of own measurements using
photo ionization mass spectrometry. This includes photo fragmentation,
spectra of low pressure flames, coagulation effects, and nanoparticle
measurements in the exhaust gas of a sooting normal pressure
premixed flame well outside of the visible zone. A model on
nanoparticle formation is discussed as are its implications
on emissions of vehicle engines.
[Back to top]
Polymer/Metal Nanocomposites: Assembly of Metal Nanoparticles
in Polymer Films and their Applications
Shin Horiuchi and Yukimichi Nakao
We have developed a simple dry process to assemble metal
nanoparticles in polymer films in two- and three- dimensions
in multi-length scales. The vapor of bis(acetylacetonato)palladium(II)
(Pd(acac)2) is reduced by
polymers without additional reducing agents in N2
atmosphere at 180 °C, and Pd metal nanoparticles are produced
in the polymer films with excellent size uniformity and stabilization.
We showed the self-assembly of Pd nanoparticles into selective
nanodomains in block copolymer (BC) films to provide three-dimensional
layer-by-layer arrangements and hexagonally arranged spherical
nanodomains. In addition to this “bottom-up” approach
for the construction of well-ordered polymer/metal nanocomposites,
we have also developed a “top-down” approach that
enables the assembly of Pd nanoparticles by UV photolithography.
Properties of polymer/metal nanocomposites thus prepared have
potentials for functional materials and fabrications of nanodevices
by ensemble of unique properties of metal nanoparticles and
polymers.
[Back to top]
Deposition of Ru-Ni-S Nanoparticles on Carbon by Spray-Pyrolysis:
Effects of Solvent and other Processing Parameters
Kalyana C. Pingali, Shuguang Deng and David A. Rockstraw
Nanoparticles of Ru-Ni-S were synthesized in a single-step
spray-pyrolysis process as potential catalysts for fuel cells
and other applications. The liquid precursors containing ruthenium,
nickel, and sulfur were nebulized by an ultra-sonic atomizer
to generate aerosol droplets, which were subsequently decomposed
to form uniformly distributed nanoparticles for deposition
on a carbon thin film. It was observed that the application
of methanol as solvent has a strong effect on the particle
morphology, size, and composition. The morphology of the Ru-Ni-S
nanoparticles changed from spherical with water as solvent,
to dendrites upon increase in the methanol concentration in
the precursor solution. It was also found that the pyrolysis
temperature strongly affected the particle morphology when
methanol was used as solvent. High temperatures promote dendrite
formation. When a water/methanol mixture was used as solvent,
crystalline ternary nanoparticles of Ru-Ni-S on a carbon layer
were formed at lower temperatures. A very interesting and
unique structure of spherical clusters of crystalline particles
attached by a chain of crystalline nanoparticles was synthesized.
Elemental analysis obtained with EDS attached to the SEM used
for particle characterization has confirmed the existence
of all elements of interest, and X-ray mapping showed all
elements were distributed uniformly in the nanoparticles.
[Back to top]
Direct Coating of Particles by a Liquid Phase Process
Yoshio Kobayashi, Shunchao Gu, Daisuke Nagao and Mikio
Konno
This review describes our studies on preparation of core-shell
particles with a direct coating technique based on a liquid
phase process and their several properties. Various particles
were successfully silica-coated with surface modification
agents and alkoxide. For Au and Ag nanoparticles, optical
spectra of the coated particles agreed with predictions by
Mie theory. For metallic Co nanoparticles, crystallization
of the Co was promoted with annealing in air with no oxidation
of the Co, and the crystallized particles revealed magnetic
properties. The silica-coated fluorescence polystyrene microspheres
showed more stable fluorescence to laser-irradiation than
uncoated microspheres. Besides, silica-coating of AgI, Fe3O4,
CoPt and PtRu particles were also successfully performed.
Polystyrene and titania could be also used as shell materials.
With the use of titania-coated polystyrene particles as precursor,
hollow titania spheres could be fabricated by removing polystyrene
core from the coated particles with annealing in air. Jingle
bell-shaped hollow spheres were fabricated with removal of
polystyrene from multilayered particles composed of a silica
core, a polystyrene inner shell, and a titania outer shell
by immersing them in tetrahydrofuran. Titania-coated silica
particles were used for fabrication of colloidal crystals.
[Back to top]
Comparative Study of the Required Force for Performing
Equal Channel Angular Extrusion with Routes A and C
J. León, C. J. Luis, R. Luri, B. Huarte and I.
Puertas
Equal Channel Angular Extrusion (ECAE) is an innovative technique
whose importance has grown in recent years. With this process
micrometer or even nanometer grain size is obtained in processed
materials. With this grain reduction after thermal treatments,
the mechanical properties of the billet are greatly increased.
Because the cross section does not change after one passage
through the angular channel, it is possible to introduce more
deformation in the material, repeating the process several
times for the same billet. Depending on how the repetitions
are made, different deformation distribution can be obtained
in the material. In this work a comparison of routes A and
C has been made for an aluminium alloy 5083, between deformation
obtained and force required to carry out each passage.
[Back to top]
Dendritic Functionalization of Metal Nanoparticles
for Nanoparticle-Cored Dendrimers
Young-Seok Shon and Daeock Choi
This paper presents a concise review of synthetic strategies
for nanoparticle-cored dendrimers from metal nanoparticles,
with an emphasis on their current applications. The synthesis
of nanoparticle-cored dendrimers represents an important advance
to the control and preparation of new organized nanostructures.
The most popular way for the synthesis of nanoparticle-cored
dendrimers is a direct method using a modified Schiffrin reaction
with dendrons containing thiol or disulfide groups. The second
method is an indirect method involving two-step reactions,
the synthesis of monolayer-stabilized nanoparticles followed
by the ligand-place exchange with thiolated-dendrons. Thirdly,
a new synthetic strategy to build dendritic architectures
around a monolayer-protected nanoparticle using single or
multi-step organic reactions is described. Two different approaches
for this new synthetic method are attempted. Convergent approach
is based on a strategy in which the synthesis of monolayer-protected
nanoparticles is followed by adding dendrons on nanoparticles
by a single coupling reaction. Divergent approach uses multi-step
reactions to build dendritic architectures around a nanoparticle
core. Incorporation of a redox molecule on the surface of
core nanoparticle in nanoparticle-cored dendrimers results
in the formation of redox-active nanoparticle-cored dendrimers.
[Back to top]
Preparation and Characterization of Free-Standing
Cyclotrimethylenetrinitramine (RDX) Films with a Gelatin as
Matrix
Qing-Ping Luo, Chong-Hua Pei, Fu-De Nie, Zhao-Qian Li,
Guang-Cheng Yang and Hui Huang
Cyclotrimethylenetrinitramine (RDX), also known as cyclonite,
hexogen and T4, is an explosive
nitroamine. RDX is considered one of the most powerful military
explosive, and has a tremendous force shattering effect from
the sudden release of energy. In this article, free-standing
RDX film was prepared by using a bacterial cellulose gelatin
as matrix. The RDX particles in the film tightly cling to
the network of gelatin, and the granularity distribution of
RDX is very uniform in the range of 30-45 nm. The average
contents of the RDX in the films are more than 81% when the
RDX concentrations in the soaking solutions are more than
0.05 g/ml. The decomposition temperature of RDX in the film
is found to decrease approximately 20°C compared with
that of raw micro-size RDX. The film was characterized with
X-ray diffraction (XRD), scanning electron microscopy (SEM),
high performance liquid chromatography (HPLC), thermogravimetry
(TG) and Differential Scanning Calorimetric (DSC).
[Back to top]
Adsorption of Sodium Oleate on Nano-sized Fe3O4 Particles
Prepared by Co-precipitation
Xingping Zhou, Siyu Ni, Xiaqin Wang and Fan Wu
Nano-sized Fe3O4
is one of the most important magnetic materials wildly applied
in various fields and sodium oleate (SO) is a very useful
anionic surfactant for dispersing nano-particles in aqueous
solution in the practical applications of nano-particles.
However, studies of its adsorption properties on Fe3O4
nano-particles are scarce. This work firstly characterized
the shape, size and phase structure of the nano-sized magnetite
(Fe3O4)
particles synthesized with chemical co-precipitation in aqueous
solution by transmission electron microscopy (TEM) and X-ray
diffraction (XRD). Then, the UV absorbance behaviors of sodium
oleate (SO) aqueous solution were explored and the adsorption
of SO on nano-sized Fe3O4
particles was carried out. Based on the UV characteristics
of SO, the isothermal adsorption of SO on these magnetite
nanoparticles was measured under pH 10.5 at room temperature.
Meanwhile, Fourier-transform infrared spectroscopy (FT-IR)
was used to confirm the attachment of SO on the magnetic particles.
Moreover, the adsorption equilibrium isotherm was fitted well
by the Langmuir mode and proved that this adsorption was a
monolayer adsorption.
[Back to top]
Micromorphology of the Yellow Cuticle in Social Wasps:
The Presence of Rhabdomeric and Ciliary Peripheral Photoreceptors
Jacob S. Ishay, Marian Plotkin, Reuben Hiller, Stanislav
Volynchik and David J. Bergman
Social hornets (Hymenoptera, Vespinae) are colorful organisms
in that between their segments of brown cuticle there are
stripes which outwardly appear of a different color. The Oriental
hornet Vespa orientalis bears two yellow stripes
on its gastral cuticle and yellow plates on its vertex. In
other vespan species the number of yellow stripes varies.
Microscopic examination of the so-called yellow cuticle reveals,
beneath about 30 layers of transparent cuticle, a relatively
thick stratum of yellow pigmented granules. At intervals of
10-50µm apart, one can see extrusions emerging from
peripheral photoreceptor cells and proceeding upward to the
epicuticular layer. Underneath the mentioned cuticular layers,
the photoreceptor cell broadens to contain at its periphery
a rhabdom-shaped structure which bears dark pigment granules
on its surface. Outside the membrane of the photoreceptor
but abutting it are numerous yellow granules which are interconnected
by branches. Thus all the photoreceptor cells and all the
yellow granules beneath the yellow cuticle in each yellow
stripe are bound to one another to form a single tissue. Each
photoreceptor cell is synaptically linked with a single nerve
extension, which renders it bipolar. These neural extensions,
in turn, are interlinked to form a network or rete. The various
elements of the photoreceptor, and particularly its extension
and the yellow granules, are endowed with a network of contractile
fibrils (myoids) that supposedly can regulate the uptake of
light. Since the entire structure is comprised of rhabdom-shaped
photoreceptors surrounded by numerous interconnected yellow
granules that originate from cilia, what we have here basically
is an array made up of few villi-shaped photoreceptors and
an abundance of cilia (about 10.000). We suspect that this
entire array serves to pick up light energy and convert it
to readily available energy that is transmitted via neural
fibers for use by the hornet.
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