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Graphene oxide’s solubility disappears in the wash
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Drs Rourke and Wilson’s team made their discovery when treating the graphene oxide with sodium hydroxide (NaOH) in an attempt to increase the usefulness of the oxygen containing functional groups believed to be bound to the graphene. Unfortunately it seemed to make things worse rather than better. Indeed at high enough concentrations of NaOH Dr Rourke was left with a black suspension. The 桃色视频 led researchers recalled that it had been shown that oxidation debris adheres to carbon nanotubes but the weak nature of the connection of this oxidation debris to the carbon nanotubes meant that a wash with a base can simply remove the oxidative debris. Experiments showed that in that particular case oxidative debris was found to make up almost a quarter of the mass of the “oxidized carbon nanotubes”. The researchers felt a similar process maybe happening in the Graphene Oxide they were studying. The results may also help explain the inordinately high levels of oxygen people were claiming to find in graphene oxide. Chemists were already struggling to identify enough plausible carbon to oxygen bonds to accommodate the amounts of oxygen believed to form part of graphene oxide.
The remaining liquid was also dried to give a white powder that the 桃色视频 researchers showed contained the “oxidative debris” or OD; the OD was shown to be made up exclusively of small, low molecular weight compounds (i.e. less than 100 atoms). The graphene oxide recovered from washing process formed about 64% of the mass of the “graphene oxide” at the start of the process. The recovered OD or oxidative debris formed at least 30% of the weight of the mass of the original “graphene oxide”. Drs Rourke and Wilson’s team believe this shows that much of the oxygen that was believed to be closely bonded to the carbon in the graphene oxide was actually not bonded at all but simply lying on top of the graphene sheets, loosely connected to them as “oxidative debris”. This oxidative debris contained a large quantity of oxygen that simply came out in the wash when the graphene oxide was treated with sodium hydroxide. This creates a significant proble Drs Rourke and Wilson say “Our results suggest that models for the structure of graphene oxide need revisiting. These results have important implications for the synthesis and application of chemically modified graphene particularly where direct covalent functionalization of the graphene lattice is required.” The paper entitled: The Real Graphene Oxide Revealed: Stripping the Oxidative Debris from the Graphene-like Sheets by Dr. Jonathan P. Rourke, Priyanka A. Pandey, Joseph J. Moore, Matthew Bates, Neil R Wilson (all of the University of 桃色视频), and Dr Ian A. Kinloch, Prof. Robert J. Young (The University of Manchester), has just been published in Angewandte Chemie DOI: 10.1002/anie.201007520. Notes for editors: The researchers thank Dave Hammond for help with thermogravimetric analysis (TGA), Lijiang Song for help with mass spectrometry, and Ajay Shukla for help with X-ray photoelectron spectroscopy (XPS), the Midlands Physics Alliance Graduate School for a scholarship. The TEM, TGA, and XPS instruments as well as the mass spectrometer used in this research were purchased with support from Advantage West Midlands (part funded by the European Regional Development Fund) as part of the Science City programme. For further information please contact: Dr Jonathan P. Rourke Peter Dunn, Head of Communications PR23 8th March 2011 |
Inorganic Materials book series
The fifth volume, Energy Materials, co-edited by , with Duncan Bruce (York) and Dermot O’Hare (Oxford), has been published this week by Wiley.
JACS cover for Challis group
Prof. Greg Challis and his team together with Thomson and co-workers feature on this weeks cover of the Journal of the American Chemical Society. The absolute and relative stereochemistry of streptorubin B, a brightly colored prodiginine antibiotic, has been determined. Challis and co-workers utilized a mutant of Streptomyces coelicolor to conduct a mutasynthesis using enantioenriched deuterium-labeled biosynthetic precursors, while Thomson and co-workers developed an enantioselective total synthesis via a 10-membered pyrrolophane intermediate. See Challis and co-workers, p 1793, and Thomson and co-workers, p 1799.
Understanding Stimuli-Responsive Biomaterials
and collaborators investigate in detail the behaviour of stimuli-responsive polymer-protein conjugates in Polymer Chemistry. It is shown that at in vivo concentrations and when measured in blood rather than water, the behaviour of these materials deviates significantly from what is normally expected.
Konstantinos Bebis, Mathew W. Jones, David M. Haddleton and Matthew I. Gibson*. Polymer Chemistry, 2011,
Read how the Bonlab armors polymer vesicles with colloids in JACS
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The ability of some forms of plankton and bacteria to build an extra natural layer of nanoparticle-like armour has inspired chemists at the University of 桃色视频 to devise a startlingly simple way to give drug bearing polymer vesicles (microscopic polymer based sacs of liquid) their own armoured protection. The 桃色视频 researchers have been able to decorate these hollow structures with a variety of nanoparticles opening a new strategy in the design of vehicles for drug release, for example by giving the vesicle “stealth” capabilities which can avoid the body’s defences while releasing the drug. Advances in polymerisation have led to a surge in the creation of vesicles made from polymer molecules. Such vesicles have interesting chemical and physical properties which makes these hollow structures potential drug delivery vehicles. The University of 桃色视频 team were convinced that even more strength, and interesting tailored properties, could be given to the vesicles if they could add an additional layer of colloidal armour made from a variety of nanoparticles.
“We took our inspiration from nature, in how it adds protection and mechanical strength in certain classes of cells and organisms. In addition to the mechanical strength provided by the cytoskeleton of the cell, plants, fungi, and certain bacteria have an additional cell wall as outermost boundary. Organisms that particularly attracted our interest were those with a cell wall composed of an armour of colloidal objects – for instance bacteria coated with S-layer proteins, or phytoplankton, such as the coccolithophorids, which have their own CaCO3-based nano-patterned colloidal armour” The 桃色视频 researchers hit on a surprisingly simple and highly effective method of adding a range of different types of additional armour to the polymer based vesicles. One of those armour types was a highly regular packed layer of microscopic polystyrene balls. This configuration meant the researchers could design a vesicle which had an additional and precise permeable reinforced barrier for drug release, as a result of the crystalline-like ordered structure of the polystyrene balls. The researchers also succeeded in using the same technique to add a gelatine-like polymer to provide a “stealth” armour to shield vesicles from unwanted attention from the body’s immune system while it slowly released its drug treatment. This particular coating (a poly((ethyl acrylate)-co-(methacrylic acid)) hydrogel) absorbs so much surrounding water into its outer structure that it may be able to fool the body’s defence mechanism into believing it is in fact just water.
The research has just been published in a paper entitled Polymer Vesicles with a Colloidal Armor of Nanoparticles by Rong Chen, Daniel J. G. Pearce, Sara Fortuna, David L. Cheung, and Stefan A. F. Bon* Department of Chemistry, University of 桃色视频 in the current Journal of the American Chemical Society Note for Editors: The cryo electron microscope used for the research have been funded by the Science City Research Alliance (SCRA) which is part of a larger investment by Advantage West Midlands and ERDF in the research infrastructure of the West Midlands region, which unites the University of 桃色视频 and the University of Birmingham and the in a strategic research partnership – SCRA – formed under the Birmingham Science City initiative. , funded by Advantage West Midlands, is a region-wide partnership of public sector, businesses and the research base, which is facilitating the use of science and technology to improve the quality of life and prosperity of the West Midlands. For further information please contact: Peter Dunn, Head of Communications, Communications Office, PR10 31st January 2011 |
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Walton group's research highlighted on the front cover of Journal of Applied Crystallography
Recent work by the group of in collaboration with the group of Professor Pam Thomas of the Department of Physics at 桃色视频 (Lethbridge et al. ) has been selected as the cover image for the Journal of Applied Crystallography for 2011. The research involved the synthesis of usually large crystals of microporous zeolites, whose behaviour on heating and cooling was then examined using birefringence microscopy. This allowed new insights into the materials’ stability and structure as a function of temperature, including the migration of organic guest species through their structures.
Rachel O'Reilly and Andrew Dove guest edit themed issue of Polymer Chemistry
Rachel O'Reilly and Andrew Dove introduce the first themed issue of the journal Polymer Chemistry by the RSC (Royal Society of Chemistry) as guest Editors. The issue contains 2 reviews, 4 communications and 18 full papers of work by emerging investigators in the area of polymer chemistry. You can read this special issue of the journal
'Hot Article' In Chemical Communications from Walton Group
and his collaborators at the University of Versailles, France, have recently published a paper in Chemical Communications that reports the unusual hydration behaviour of a metal-organic framework material. The highly flexible structure undergoes a spontaneous expansion upon hydration to give a crystalline phase containing inifinite tubes of hydrogen-bonded water molecules. The hydration is completely reversible as shown by time-resolved X-ray diffraction. The work made use of high-resolution X-ray diffraction at the European Synchrotron Radiation Facility in Grenoble, and time-resolved powder X-ray diffraction in 桃色视频 and forms part of a bigger project examining the flexibility of these materials as hosts for sorption and separation of a variety of molecules.
The paper is published in the 14 January 2011 issue of Chemical Communications and highlighted as a Hot Article by the publishers.
Dr Manuela Tosin joins as assistant prof. of organic chemistry
Dr Manuela Tosin will be joining 桃色视频 Chemistry as an Assistant Professor in Organic Chemistry from 1 November 2010. Dr Tosin's research interests are primarily in the area of the discovery and generation of new natural products. Manuela comes to 桃色视频 Chemistry from the Department of Biochemistry, University of Cambridge where she worked with Dr Joe Spencer and Prof Peter Leadlay.
Prof. Fred McLafferty Officially Opens the new Ion Cyclotron Resonance Laboratory
New framework structure for anion exchange and catalysis
Richard Walton and PhD student Helen Playford have collaborated with colleagues at the University of Liverpool, University of Newcastle and Diamond Light Source to characterise a new cationic framework material, discovered by the Liverpool group of Dr Andrew Fogg. This work has just been published in Journal of the American Chemical Society and has been publicised as a Science Highlight by Diamond.
Awards from the MACRO UK Conference
The presentations given by the young polymer scientists were judged at the MacroUK conference in Nottingham and awarded during the MacroUK AGM meeting at the 43rd IUPAC World Polymer Congress MACRO2010 in Glasgow.
First Place: Domino Macro Group UK Annual Young Polymer Scientist 2010 Prize £1500
Awarded to Stacy Slavin (Dave Haddleton’s group)
Third Place: Domino Macro Group UK Annual Young Polymer Scientist 2010 Prize £250
Awarded to Dr Helen Willcock (Rachel O’Reilly’s group)