|
 |
This cover was designed by Dr. Jingwei Xie for an article
published in ACS NANO (2009, 3, pp. 1151-1159). It shows
neurites outgrowing
from Dorsal Root Ganglia (DRG) on a two-dimensional mesh of
electrospun nanofibers with orthogonal orientations. This
research provides valuable information pertaining to the design
of nanofiber-based scaffolds for neuroregenerative applications,
as well as the effects of topology on neurite outgrowth, growth
cone guidance, and axonal regeneration. |
|
 |
This cover was designed by Dr. Byungkwon Lim for a major review
article published in Angewandte Chemie International Edition
(2009, 48, pp. 60-103). It illustrates the connections between
atomic species (in the center) to metal nanocrystals with
various shapes (the outer circle) through the seeds having
different numbers of twin defects (the inner circle). Once the
seed is fixed, the final shape displayed by the metal
nanocrystal will be determined by the growth rates along
different directions through the use of a capping agent. |
|
 |
This cover was designed by Dr. Yujie Xiong for a communication
published in Angewandte Chemie International Edition
(2007, 46, pp. 790-794). It shows the roles of citrate or citric
acid as a capping agent to preferentially bind to Pd{111} facets
and to protect the highly twined Pd icosahedron from dissolution
by shielding the oxygen from air -- a critical component for
oxidative etching. As a result, Pd icosahedra could be obtained
with a yield as high as 80%. |
|
 |
This cover was designed by Professor Hong Yang at U. of
Rochester for a special section on bionanotechnology published
in Advanced Materials
(2007, 19, p. 3085). This special section was co-edited by
Professors Hong Yang and Younan Xia, and covers a broad range of
subjects related to the synthesis of nanomaterials for
biomedical applications (e.g., sensing, imaging, diagnosis, and
treatment), as well as the use of biological principles in the
design and fabrication of novel, improved nanomaterials (e.g.,
biomimetics). |
|
 |
This cover was designed by Matthew Rycenga (Ph.D., 2006-2010)
for a communication published in Advanced Materials
(2008, 20, pp. 2416-2420). It shows the self-assembly of silver
nanocubes (~100 nm in edge length) into dimers, chains, and
three-dimensional crystal lattices. The self-assembly can be
programmed and controlled by selectively modifying different
faces of the nanocubes with a hydrophobic, alkanethiolate
monolyer. For example, dimers formed when only one of the six
faces is rendered hydrophobic. |
|
 |
This cover was designed by Brian Mayer (Ph.D., 1999-2003) for a
special issue published in Advanced Materials (2004, 16,
p. 1245). The special issue was dedicated to Professor George M.
Whitesides on the occasion of his 65th birthday. It includes an
interview of Whitesides, 18 review articles, research news
articles, and communications by his former students and
postdoctoral fellow, with a focus on "soft lithography". It also
contains a very useful essay by Whitesides on how to write a
scientific paper (p. 1375). |
|
 |
This cover was designed by Dr. Hiroshi Fudouzi (a visiting
scientists from NIMS in Japan) for a communication published in
Advanced Materials (2003, 15, pp. 892-896). It shows how to use
colorless inks to print colorful images on photonic paper -- a
composite material fabricated by infiltrating an opal lattice of
polymer beads with an elastomer such as poly(dimethyl siloxane)
(PDMS). When the PDMS matrix was swollen with a silicone fluid,
the lattice constant and thus the wavelength of diffracted light
increased. |
|
 |
This cover was designed by Brian Mayer (Ph.D., 1999-2003) for a
special issue on nanowires published in Advanced Materials
(2004, 16, p. 1245). The special issue was co-edited by
Professors Younan Xia and Peidong Yang. It includes 18 review
articles, research news articles, and communications on the
synthesis, chemistry, physics, and technological applications of
metal and semiconductor nanowires. The review article by Xia,
Yang, and their co-workers is the most cited paper published in
Advanced Materials. |
|
 |
This cover was designed by Byron Gates (the first Ph.D.,
1999-2001) for a communication published in Advanced
Materials (2000, 13, pp. 1605-1608). It shows the tuning of
colors displayed by a photonic crystal with an external magnetic
field. The photonic crystal was fabricated by co-self-assembly
of polymer latex beads and superparamagnetic iron oxide
nanoparticles. After solidification, the polymer beads were
selectively removed, generating an inverse opal composed of the
sintered iron oxide nanoparticles. |
|
 |
This cover was designed by Yadong Yin (Ph.D., 1998-2002) for a
communication published in Advanced Materials (2000, 12,
pp. 1426-1430). It shows scanning electron micrograph of
free-standing nanorings of single-crystal silicon that were
fabricated by patterning silicon-on-insulator (SOI) wafer with
phase-shifting, near-field optical lithography, followed by
lift-off. This simple technique can also be extended to
fabricate single-crystal silicon nanostructures with many
different shapes or morphologies. |
|
 |
This cover was designed by Brian Mayer (Ph.D., 1999-2003) for a
communication published in Advanced Materials
(2002, 14, pp. 279-282). It shows transmission electron
micrograph of tellurium nanotubes at different stages of growth.
The success of this synthesis is based upon the formation of a
concentration depletion zone on the seed by controlling the
reduction rate of a tellurium precursor. As such, tellurium
atoms were preferentially added to the edges of the seed,
leading to the formation of a nanotube. |
|
 |
This cover was designed by Byron Gates (the first Ph.D.,
1999-2001) for a special issue on photonic crystals published in
Advanced Materials (1999, 13, p. 369). It shows scanning
electron micrograph of an inverse opal of silica fabricated by
infiltrating the voids in an opal lattice of polystyrene beads
with a sol-gel precursor, followed by selective removal of the
polystyrene beads by dissolution with an organic solvent. The
special issue was edited by Professor Younan Xia and includes 23
articles from various groups. |
|
 |
This cover was designed by Dr. Sang Hyun Park (the first
postdoctoral fellow) and Byron Gates (the first Ph.D.,
1999-2001) for a
communication published in Advanced Materials
(1999, 11, pp. 462-466). It shows scanning electron micrograph
of three-dimensional lattice assembled from polystyrene beads in
a fluidic cell (see the center for a photograph). Such a
crystalline lattice is able to diffract light at a specific
wavelength (as determined by the Bragg's law) and function as a
photonic crystal with a pseudo band gap. |
|
|
This cover was designed by Yadong Yin (Ph.D., 1998-2002) for a
feature article published in Advanced Functional Materials
(2003, 13, pp. 907-918). It shows scanning electron micrograph
of an array of colloidal clusters (or molecules) fabricated
using template-assisted self-assembly (TASA). The key is to
control the sizes of the templates (e.g., cylindrical holes
patterned in a photoresist film) relative to the diameter of the
polymer beads or other types of building blocks, which could be
small as tens of nanometers. |
|
 |
This cover was designed by Dr. Marta Ibisate (a visiting
scientist from Spain who was supported by a Fulbright
Fellowship) for an article published in Advanced Functional
Materials (2006, 16, pp. 1627-1632). It shows scanning
electron micrograph of dimers assembled from silica spheres. By
controlling the interaction potential between colloidal spheres
of silica , they could be induced to form dimers, which could be
fixed by adding a sol-gel precursor to silica into the reaction
system. The yield could be as high as 80%. |
|
 |
This cover was designed by the editorial office for a special
issue published in Advanced Materials (1999, 11, p.
1065). The special issue was co-edited by Professors Younan Xia
and Rukang Li and was dedicated to all materials scientists in
China, with a focus on "materials research in China: successes
and problems". It includes 15 review articles, research news
articles, and communications on a broad range of subjects
related to materials science and engineering, as well as an
essay on the funding mechanism and trend. |
|
 |
This cover was designed by Yadong Yin (Ph.D., 1998-2002) for a
feature article published in Australian Journal of Chemistry
(2001, 54, pp. 287-290). It shows fluorescence optical
micrograph of dimers assembled from polystyrene beads doped with
two different organic dyes. The dimers were formed using a
process developed by the Xia group and now known as
template-assisted self-assembly (TASA). By choosing the right
dimensions for the template, one can only place a specific
number of polymer beads in each template. |
|
 |
This cover was designed by Benjamin Wiley (Ph.D., 2002-2006) for
a concepts article published in Chemistry: A European Journal
(2006, 11, pp. 454-463). It illustrates the synthesis of silver
nanocrystals with different shapes via the polyol process, which
involves reduction of silver nitrate with ethylene glycol at an
elevated temperature in the presence of poly(vinyl pyrrolidone)
(PVP). By varying the experimental conditions, one can obtain
silver nanocrystals with different shapes, including nanocubes
and nanowires. |
|
 |
This cover was designed by Dr. Yujie Xiong for a communication
published in Journal of Materials Chemistry (2007, 17,
pp. 2600-2602). It shows transmission electron micrograph (TEM)
of silver nanoplates in the background and high-resolution TEM
of the cross section of such a silver nanoplate, showing the
stacking faults along the vertical direction. This synthesis is
based upon the polyol reduction of silver nitrate in the
presence of polyacrylamide, which can form complex with silver
ions and thus slow down the reduction. |
|
 |
This cover was designed by Jesse McCann (Ph.D., 2002-2006) for a
feature article published in Journal of Materials Chemistry
(2005, 15, pp. 735-738). It shows how the spinneret (see the
center for a coaxial configuration) for electrospining can be
modified to fabricate nanofibers with a wide range of different
morphologies, including tubular fibers (upper left corner),
porous fibers (upper right corner), and nanotubes with
selectively functionalized inner or outer surface (lower
corners). |
|
 |
This cover was designed by Benjamin Wiley (Ph.D., 2002-2006) for
a feature article published in the Journal of Physical
Chemistry B (2006, 110, pp. 15666-15675). It shows the
formation of silver nanocubes, pentagonal nanowires, and right
bipyramids from atoms through three different types of seeds:
single-crystal cubooctahedron, multiply twinned decahedron with
a five-fold axis, and singly twinned, respectively. Such a shape
control enables one to maneuver the optical (plasmonic)
properties of silver nanocrystals. |
|
 |
This cover was designed by Jingyi Chen (Ph.D., 2002-2006) for a
feature article published in Langmuir (2007, 23,
4120-4129). It shows a scanning electron micrograph of platinum
sea urchins -- aggregates of platinum nanoparticles whose
surfaces are decorated with single-crystal platinum nanorods or
nanowires. The key to the formation of platinum nanowires is to
slow down the reduction of a platinum precursor via oxidative
etching, by simply introducing ferric or ferrous species into
the reaction system. |
|
 |
This cover was designed by Yu Lu (Ph.D., 1999-2003) for an
article published in Langmuir (2001, 17, pp. 6344-6350).
It shows scanning electron micrograph of the cross section of a
crystalline lattice self-assembled from polystyrene beads. This
article describes a simple method based upon a fluidic cell for
assembling polystyrene latex beads into three-dimensional opals
with long-range order. The fluidic cell could be easily
fabricated by sandwiching a gasket (cut from a Mylar film)
between two glass slides. |
|
 |
This cover was designed by Dr. Jingwei Xie for a review article
published in Macromolelcular Rapid Communications (2008,
29, pp. 1775-1792). It shows the basic setup for electrospinning
and the use of electrospun nanofibers for various biomedical
applications, including their use as scaffolds for tissue
engineering. For example, uniaxially aligned nanofibers can be
utilized to manipulate the differentiation of stem cells, and to
guide and enhance the outgrowth of neurites. Such abilities are
highly sought in nerve repair. |
|
 |
This cover was designed by Benjamin Wiley (Ph.D., 2002-2006) for
a special issue published in Materials Research Society (MRS)
Bulletin (2005, 30, p. 338). The special issue was co-edited
by Professors Younan Xia and Naomi Halas, with a focus on the
plasmonic properties of metal nanoparticles. It includes
six review articles on the synthesis and characterization of
silver and gold nanostructures, as well as their surface plasmon
resonance (SPR) properties and applications in sensing or
surface-enhanced Raman scattering (SERS). |
|
 |
This cover was designed Yu Lu (Ph.D., 1999-2003) for a paper
published in Nano Letters (2002, 2, pp. 785-788). It
shows scanning electron micrograph (in the back-scattering mode)
of a crystalline lattice assembled from gold@silica core-shell
colloidal spheres. Since gold has a higher atomic number than
silicon, one can clearly see the gold cores even though they are
enclosed in silica shells. Such core-shell particles offers a
new class of building blocks for fabricating photonic crystals
with additional plasmonic features. |
|
 |
This cover was designed by Dr. Unyong Jeong for an article
published in Nature Materials (2005, 4, pp. 671-675). It
shows a colorized scanning electron micrograph of polystyrene
beads with hollow interiors and controllable pores in their
surfaces. This novel class of colloidal particles were
fabricated by swelling solid polymer beads with a proper
solvent, followed by freeze-drying. A combination of phase
separation and solvent evaporation results in the formation such
hollow, porous polymer beads useful in encapsulation. |
|
 |
This cover was designed by Byron Gates (the first Ph.D.,
1999-2001) for a news article published in Northwest
Technology, a magazine that aims to feature new
technological developments in the northwest region, mainly from
the U. of Washington. It shows scanning electron micrograph of
an opal lattice of polystyrene beads. In this article, it
highlights some of the exciting research from Xia group related
to the fabrication of photonic crystals from colloidal building
blocks through a self-assembly approach. |
|
 |
This cover was designed by Dr. Sung-Wook Choi for a paper
published in Small (2009, 4, pp. 454-459). It shows
optical micrographs of polymer beads with uniform sizes in the
range of 30-300
mm
that could be easily produced using a simple fluidic device
constructed from a syringe needle, a glass capillary, and a PVC
tube. The uniform polymer beads could be assembled into
three-dimensional lattices and further utilized as templates to
produce inverse opal scaffolds with uniform pore sizes for
tissue engineering. |
|