Archive for the ‘Hot Article’ Category

Hot paper: Feature article of soft X-ray characterisation of organic semiconductor films

This Feature Article by McNeill and Ade reviews the characterisation of the structural composition and morphology of thin film organic semiconductors using different X-ray techniques. The authors discuss six different applications of soft X-rays including scanning transmission X-ray microscopy (STXM); resonant X-ray scattering; resonant X-ray reflectivity; near-edge X-ray absorption fine-structure spectroscopy; polarized STXM and polarized soft X-ray scattering. The authors conclude that soft X-ray techniques have great potential for unravelling the complex structures shown by organic semiconductor blends and multilayers.

Soft X-ray characterisation of organic semiconductor films
J. Mater. Chem. C, 2013, Advance Article.  DOI: 10.1039/c2tc00001f
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: Layer-by-layer coating of alginate matrices with chitosan–alginate

It is postulated that probiotic bacteria play a role in maintaining good health and they have been shown to alleviate the symptoms of some common conditions such as traveller’s diarrhoea. If the bacteria are to be ingested orally, they must withstand an acid challenge in the stomach before they can reach the intestine to act. A common strategy to reduce bacterial cell death is encapsulation, usually using a polymer matrix. The naturally occurring polysaccharide alginate is the most popular probiotic encapsulation-based material.

In this hot paper, Khutoryanskiy, Charalampopoulos and co-workers evaluate the production of alginate matrices coated with multilayers of alternating alginate and chitosan as viable encapsulation materials for probiotic bacteria. The authors show, that the multilayers are stable in both simulated gastric and intestinal solutions, with encapsulation in 3-layer coated matrices giving the highest recovery of viable cells. It is suggested that this method of encapsulation could be used to protect orally administrated probiotics from the low pH of the stomach.

Layer-by-layer coating of alginate matrices with chitosan–alginate for the improved survival and targeted delivery of probiotic bacteria after oral administration
J. Mater. Chem. B
, 2013, Advance Article.  DOI: 10.1039/c2tb00126h (free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

It is postulated that probiotic bacteria play a role in maintaining good health and they have been shown to alleviate the symptoms of some common conditions such as traveller’s diarrhoea. If the bacteria are to be ingested orally, they must withstand an acid challenge in the stomach before they can reach the intestine to act. A common strategy to reduce bacterial cell death is encapsulation, usually using a polymer matrix. The naturally occurring polysaccharide alginate is the most popular probiotic encapsulation-based material.

In this hot paper, Khutoryanskiy, Charalampopoulos and co-workers evaluate the production of alginate matrices coated with multilayers of alternating alginate and chitosan as viable encapsulation materials for probiotic bacteria. The authors show, that the multilayers are stable in both simulated gastric and intestinal solutions, with encapsulation in 3-layer coated matrices giving the highest recovery of viable cells. It is suggested that this method of encapsulation could be used to protect orally administrated probiotics from the low pH of the stomach.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: First thermodynamically-controlled synthesis of iron pyrite nanocrystals

Iron pyrite (fool’s gold, FeS2) has a high absorption coefficient and an indirect band gap of ~0.95 eV, making it a promising optoelectronic material. FeS2 is also abundant and non-toxic compared to commonly employed chalcogenides semiconductor materials. Photovoltaic investigations into FeS2 have not progressed as quickly as other materials because of its complicated synthesis control and conflicting crystal studies.

In this hot paper the Ren group report the nanoscale synthesis and characteristics of FeS2. The authors systematically change the different synthetic variables in the synthesis such as reaction temperature and chemical precursors. Five different nanocrystal shapes are observed with two different growth directions by controlling both the thermal and chemical precursor effects. The authors propose a thermodynamic model behind the shape-controlled synthesis.

Thermodynamic control of iron pyrite nanocrystal synthesis with high photoactivity and stability
J. Mater. Chem. A, 2013, Advance Article.  DOI: 10.1039/c2ta00498d
(read for free for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: Detecting explosives with crystalline frameworks

3D porous aromatic frameworks for explosives detection

For hundreds of years there have been attempts to use explosives for nefarious purposes. Unfortunately, central government can not always rely on mysterious, anonymous letters to prevent their untimely obliteration. A simple, sensitive and reliable means of detecting explosive compounds would not only have security applications; there is also a need to prevent the accidental release of explosive materials into the environment.

In a recent paper, Yuan et al. describe a three-dimensional pourous aromatic framework (PAF) with high-fluorescence quenching ability for nitro-aromatic compounds. As little as 1.5 ppm of an explosive such as TNT (2,4,6-trinitrotoluene) leads to a significant, observable decrease in luminescence intensity. Common aromatics lacking a nitro group elicit no such decrease.

The highly crystalline PAF was formed by a condensation reaction between a germanium-containing, luminescent monomer and aromatic boronic acids. The resulting polymeric framework gives the material a high fluorescence quantum yield that is easily disrupted by interactions with an analyte. The specificity for nitro-aromatics is thought to come from the attraction of electronegative nitro groups to the electron-donating PAF.

Such a sensitive material has enormous potential for use in explosives detection equipment. However, enemies of Jacobean plotters beware! This strategy might not detect gunpowder.

Sensitive detection of hazardous explosives via highly fluorescent crystalline porous aromatic frameworks

J. Mater. Chem., 2012, 22, 24558.  DOI: 10.1039/c2jm35341e

James Serginson is a guest web writer for the Journal of Materials Chemistry blog. He currently works at Imperial College London carrying out research into nanocomposites.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Journal of Materials Chemistry A, B and C Issue 1’s now online

The first issues of the newly formed Journal of Materials Chemistry A, B and C have been published online! Each journal showcases high impact research you expect from Journal of Materials Chemistry, now in three separate journals. For more information, please go to http://rsc.li/jmc-abc.

Journal of Materials Chemistry A features articles on the following:

Multifunctionality in metal@microgel colloidal nanocomposites, Jorge Pérez-Juste and Luis M. Liz-Marzán et al.: This Highlight describes recent developments related to hybrid nanocomposites comprising a metal core and a smart microgel shell.

Naturally occurring iron oxide nanoparticles: morphology, surface chemistry and environmental stability, Haibo Guo and Amanda S. Barnard : There is much to be learned from the simple and effective materials chemistry of naturally occurring nanomaterials.

Aluminum-stabilized NASICON-structured Li3V2(PO4)3, John B. Goodenough et al.: The redox couple, V4+/V3+, exhibits a potential of 3.76 V in NASICON-structured Li3Al0.1V1.9(PO4)3, which is suitable for a cathode material of a lithium-ion battery.

Importance of small micropores in CO2 capture by phenolic resin-based activated carbon spheres, Nilantha P. Wickramaratne and Mietek Jaroniec: Phenolic resin-based carbon spheres obtained by a slightly modified Stöber method are shown to be superior CO2 adsorbents.

Journal of Materials Chemistry B features articles on the following:

Biomimetic intracellular matrix (ICM) materials, properties and functions. Full integration of actuators and sensors, Toribio F. Otero and Jose G. Martinez: The electrochemistry of conducting polymers, and other organic compounds, originates biomimetic (intracellular matrix, ICM, reactive gels) materials, properties and devices here reviewed.

Cellular uptake and gene delivery using layered double hydroxide nanoparticles, Jun Lu, David G. Evans and Dermot O’Hare: The cellular uptake of fluorescein labelled 20 nm LDH nanoparticles into NSC 34 cells as a function of LDH particle concentration and incubation time was studied. The 20 nm LDH nanoparticles can also act as a DNA delivery agent to NSC 34 cell nuclei.

Biocompatible reduction-responsive polypeptide micelles as nanocarriers for enhanced chemotherapy efficacy in vitro, Xuesi Chen et al.: Biocompatible reduction-responsive micelles of disulfide-linked methoxyl poly(ethylene glycol) and poly(ε-benzyloxycarbonyl-L-lysine) block copolymers were developed for efficient intracellular drug delivery.

Theoretical understanding of single-stranded DNA assisted dispersion of graphene, Swapan K. Pati et al.: Using atomistic molecular dynamics (MD) simulation, we investigate the structure and energetic of single-stranded DNA (ssDNA) assisted solubilisation of single-layer graphene in aqueous medium at room temperature.

Journal of Materials Chemistry C features articles on the following:

Pyroelectric and electrocaloric materials, Q. M. Zhang et al.: This review summarizes typical properties of electrocaloric and pyroelectric materials and discusses related phenomena, and examines the relationship between these effects.

Graphenylene, a unique two-dimensional carbon network with nondelocalized cyclohexatriene units, Klaus Müllen and Linjie Zhi et al.: The unique structure and properties of a new hypothetical two-dimensional sp2-carbon network which is called graphenylene, have been predicted.

A deep-blue emitting charged bis-cyclometallated iridium(III) complex for light-emitting electrochemical cells, Wiebke Sarfert, Enrique Ortí, Michael Grätzel and Etienne Baranoff et al.: A cationic iridium(III) complex based on 2′,6′-difluoro-2,3′-bipyridine shows deep-blue emission in a concentrated film and is used in light-emitting electrochemical cells.

The design and investigation of porphyrins with liquid crystal properties at room temperature, Ross W. Boyle and Georg H. Mehl et al.: Porphyrins linked via hydrocarbon and siloxane spacers to cyanobiphenyls exhibit semectic LC behaviour at room temperature, confirmed by OPM, DSC and XRD.

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

C2TC00283C
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: Improvement in efficiency of water/iodide dye sensitised cells to 4%

Dye-Sensitised Solar Cells (DSSCs) are a promising alternative to silicon-based photovoltaics and recently efficiencies over 12 % have been reported. Most DSSCs use organic solvents as liquid electrolyte as these have been reported to give the highest efficiencies. In this hot paper, O’Regan and co-workers have re-examined water as a solvent for use in DSSCs. In this study the authors use 100 % water electrolytes with inorganic salts such as NaI. They use a range of electrolyte compositions, film characteristics and four different dyes to show efficiencies of up to 4 %.

Managing wetting behavior and collection efficiency in photoelectrochemical devices based on water electrolytes; improvement in efficiency of water/iodide dye sensitised cells to 4%
J. Mater.  Chem., 2012, 22, 23387.  DOI: 10.1039/c2jm35245a
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: Topotactic synthesis of layered double hydroxide nanorods

Layered double hydroxides (LDHs) are a family of layered materials with composition [M1-xz+Mx3+(OH)2]a+(Xn)a/n.mH2O. LiAl-X LDHs are a class of LDHs that have been extensively investigated due to their many applications as absorbents or in photochemistry. They can be synthesised in two ways; direct intercalation by treatment of gibbsite, bayerite or nördstrandite and hydrothermal treatment of a hydrated alumina gel with LiOH.

In this hot paper, The O’Hare group at the University of Oxford describe the first topotactic synthesis of rod-like LDH particles through that simultaneous intercalation of Li+ cations and X anions (X = Cl, and Br). Nanorods of LiAl-X were synthesised by intercalation of LiX into a rod-like morphology of gibbsite. The authors find that LiAl-X-rod can undergo further anion exchange intercalation with cyclamate into LiAl-Cl-rod.

Topotactic synthesis of layered double hydroxide nanorods
J. Mater. Chem., 2012, 22, 23064.  DOI: 10.1039/c2jm34670b
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: PVA hybrid nanocomposites containing cellulose nanocrystals and silver nanoparticles

The bacteria Gluconacetobacter xylinus produces cellulose that is highly crystalline and has a high degree of polymerisation. The cellulose can be converted into rod-like nanocrystals which have very high modulus and strength. A variety of nanocomposites can be prepared by incorporating cellulose nanocrystals with polymers to give materials with excellent properties. Silver nanoparticles are well known to improve the anti-bacterial properties of polymer materials.

Scientists in India have prepared a hybrid nanocomposite from the combination of cellulose nanocrystals and silver nanoparticles as reinforcing fillers for the polymer PVA. Both the nanocrystals and the silver nanoparticles improved the mechanical properties of the PVA films. The nanocrystals increased the modulus and tensile strength of the films, while the nanoparticles decreased the brittleness of the films. These effects could be useful in making more biocompatible materials for applications such as in tissue engineering.

Augmented properties of PVA hybrid nanocomposites containing cellulose nanocrystals and silver nanoparticles
J. Mater. Chem., 2012, 22, 22433.  DOI: 10.1039/c2jm35235d
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: imprinting photonic crystalline polymer matrices via multiple UV polymerisations

Cholesteric liquid crystals (CLCs) show selective reflection due to their helical structures. They are formed by the introduction of chiral elements into liquid crystals molecules or by doping of nematic liquid crystals with chiral dopants. Photoresponsive chiral dopants are increasing being used to fabricate tuneable CLCs.

In this hot paper, Liu and colleagues use an imprinting method which used multiple UV-induced polymerisations. A helical polymer matrix was imprinted in the presence of a CLC. Desirable Bragg reflections were found, without any added liquid crystals or chiral compounds.

Fabrication and characterization of imprinted photonic crystalline polymer matrices via multiple UV polymerizations
J. Mater.  Chem., 2012, 22, 22446.  DOI: 10.1039/c2jm35151j
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hot paper: a CdSe nanocrstyal/C60-liquid composite

Combination of inorganic nanocrystals (NCs) and organic molecules into composites have shown a variety of novel optical and electronic properties. Many of these properties arise from the inter-phase energy transfer from the excited NCs to a semiconducting matrix.

In this hot paper, Nakanishi and co-workers report the fabrication of a composite material of CdSe NCs embedded in an alkylated room temperature liquid C60 derivate. The photoelectrochemical and optical properties of the composite are investigated. It is found that the optical properties can be tuned by selection of the NC phase. Electronic band alignment between the NCs and the C60 matrix enable inter-phase charge transfer, resulting in a long-lived charge transfer state. The composite shows potential for use in sensing applications and photoelectrochemical processes.

CdSe Nanocrystal/C60-liquid composite material with enhanced photoelectrochemical performance
J. Mater. Chem., 2012, 22, 22370.  DOI: 10.1039/c2jm35294j
(free to read for a short time)

Follow the latest journal news on Twitter @JMaterChem or go to our Facebook page.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)