News

The Hatton group report in Advanced Materials a low cost window electrode for organic photovoltaics which simultaneously removes the requirement for conducting oxide and conventional low work function electrodes and functions as a sink for oxygen/water in the heart of the device. Remarkably the functionality of this electrode, which is based on a 7.8 nm nanostructured Cu:Al film, improves upon in-situ oxidation as demonstrated in bulk heterojunction organic photovoltaics.

http://onlinelibrary.wiley.com/doi/10.1002/adma.201203280/abstract

The Hatton group report in Advanced Energy Materials a lithography-free method for the fabrication of optically-thin plasmon-active metal window electrodes with a dense array of nano-sized apertures on glass and plastic substrates. These remarkably robust, low sheet resistance electrodes simultaneously concentrate light and extract charge carriers in both polymer and vacuum deposited organic photovoltaics, and outperform indium-tin oxide electrodes on flexible substrates.

http://onlinelibrary.wiley.com/doi/10.1002/aenm.201200502/abstract

Dr Joanna Geden, who is currently a Daphne Jackson Fellow in the Department, was awarded the prize for best poster at the Daphne Jackson Research Conference at the University of Bath on 24^th October 2012.

The O’Connor and Tosin groups have published work on the use of high mass accuracy tandem mass spectrometry for characterising the structures of polyketides, including erythromycin A, lasalocid A and iso-lasalocid A. They report in Analytical Chemistry on the use of Collision Activated Dissociation (CAD) and Electron Induced Dissociation (EID) as tools for determining structural information on these types of molecules. EID was shown to cause greater fragmentation of the compounds, complementary to that obtained using CAD, leading to more detailed structural information being obtained. These techniques were also combined in multistage mass spectrometry experiments, in order to use the fragmentation patterns to distinguish between lasalocid A and its isomer, iso-lasalcoid A. This work illustrates the potential of these tools and will be applied to identifying unknown polyketides and their biosynthetic intermediates.

The full article can be found at: http://pubs.acs.org/doi/abs/10.1021/ac3022778

Dr Rebecca Notman has been awarded a prestigious 5-year Royal Society University Research Fellowship starting October 2012 to pursue a research project on “Modelling the Lipid Layers of the Human Skin Barrier”.

Sadler and Stavros groups in collaboration with Prof Martin Paterson at Heriot-Watt University, publish work in Angewandte Chemie International Edition. The work describes the first demonstration of a 2-photon activated, square planar platinum (II) complex. The enhanced photolabilization demonstrated may be useful in the design of novel photoactivatable platinum chemotherapeutic agents in situations where deep tissue penetration is needed. Read the article here.

The Sadler Group report in JACS a method for switching off the cytotoxicity of a photoactivated platinum(IV) diazido complex in the A2780 human ovarian cancer cell line.

The Jones, Hatton and Shipman groups, in collaboration with Molecular Solar Ltd., demonstrate ultra-high voltage organic multijunction solar cells suitable for direct integration with batteries suitable for portable elctronics.

The group of Richard Walton have this month co-authored three papers published in the Royal Society of Chemistry journal Chemical Communications on various aspects of porous metal-organic framework (MOF) materials.

Prof Greg Challis and Dr Lijiang Song, in collaboration with researchers at the John Innes Centre, report in Chemical Science that a remarkable array of novel posttranslational modifications is involved in the assembly of the bottromycin complex of antibiotics.

Costantini and co-workers publish in Physical Review B the results of a combined experimental-theoretical work that sheds light on the atomic scale-structure of MnSi thin films grown on Si(111).

Hydrogels are an important class of materials and find use accross a wide range of disciplines. Think of for example soft contact lenses, vodka jellies, and applications in medicine for example as matrixes for regenerative tissue engineering. They can be made from watersoluble polymer molecules and form a gel through crosslinking a phenonomenon that interconnects the polymer chains creating a network. When we shrink the dimensions of the hydrogel object down and disperse them as particles in water we speak of a microgel dispersion. When we decrease the size of the hydrogel particles further, down to approximately 100 nm or less, we speak of a nanogel.

Hydrogels can be crosslinked by covalent chemical bonds or through physical crosslinking. The latter process is often found in hydrogels formed from natural polymers, such as agarose and gelatine which upon cooling in water aggregate through formation of double helices. Alginate gels can be formed by ionic crosslinking with calcium ions. Synthetic hydrogels on the other hand are conveniently formed mostly through covalent crosslinking, an important class being thermoresponsive gels (often in micro- or nanogel format) made from poly(N-isopropyl acrylamide).

Stefan Bon and his team (BonLab) now for the first time show that thermoresponsive synthetic nanogels can be made using multiple hydrogen bond arrays as non-covalent crosslinks. They replaced the covalent crosslinking monomers traditionally used in the synthesis of the nanogel dispersions with a 2-ureido-4[1H] pyrimidinone (UPy) functionalized comonomer. In their work they show that the UPy groups are capable of forming strong self-complimentary quadruple hydrogen bonds, hereby linking all the polymer chains together to form a network, creating the nanogel particle.

Stefan Bon says "we are very excited about these results as it opens up a different way of thinking in how hydrogels and nanogel dispersions can be made using the traditional synthetic route of free radical polymerization. The reversibility of the hydrogen bond formation means that these materials will have exciting physical and mechanical characteristics which potentially differ from the hydrogel materials made through covalent crosslinking"

Their findings are published in Polymer Chemistry (link to the paper), a journal by the Royal Society of Chemistry.