MacDiarmid Institute for Advanced Materials and Nanotechnology

Wellington, New Zealand

MacDiarmid Institute for Advanced Materials and Nanotechnology

Wellington, New Zealand

The MacDiarmid Institute for Advanced Materials and Nanotechnology is a New Zealand research organisation specialising in materials science and nanotechnology. It is based at Victoria University of Wellington, although it also draws on other universities and on two Crown Research Institutes.The Institute is named after Alan MacDiarmid, a New Zealander who won the Nobel Prize in Chemistry in 2000. It was established by the government as one of eight Centres of Research Excellence throughout the country.The Institute divides its work into six "themes":Nanofabrication and DevicesElectronic and Optical Materials Molecular Materials Soft Materials Hybrid Materials The Intersection of Nanoscience and Biology Wikipedia.

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Gordon K.C.,MacDiarmid Institute for Advanced Materials and Nanotechnology | McGoverin C.M.,Stellenbosch University
International Journal of Pharmaceutics | Year: 2011

Raman spectroscopy may be implemented through a microscope to provide fine scale axial and lateral chemical maps. The molecular structure of many drugs makes Raman spectroscopy particularly well suited to the investigation of pharmaceutical systems. Chemometric methods currently used to assess bulk Raman spectroscopic data are typically applied to Raman mapping data from pharmaceuticals; few reports exist where the spatial information inherent to a mapped dataset is used for the calculation of chemical maps. Both univariate and multivariate methods have been applied to Raman mapping data to determine the distribution of active pharmaceutical ingredients (APIs) in tablets, solid dispersions for increased solubility and controlled release devices. The ability to axially (depth) profile using Raman mapping has been used in studies of API penetration through membranes, cellular uptake of drug delivery liposomes, and initial API distribution and subsequent elution from coatings of medical devices. New instrumental developments will increase the efficiency of Raman mapping and lead to greater utilisation of Raman mapping for analyses of pharmaceutical systems. © 2011 Elsevier B.V.

Kaiser A.B.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Skakalova V.,Max Planck Institute for Solid State Research
Chemical Society Reviews | Year: 2011

In the years since the discovery of organic polymers that exhibited electrical conductivities comparable to some metals, other novel carbon-based conductors have been developed, including carbon nanotubes and graphene (monolayers of carbon atoms). In this critical review, we discuss the common features and the differences in the conduction mechanisms observed in these carbon-based materials, which range from near ballistic and conventional metallic conduction to fluctuation-assisted tunnelling, variable-range hopping and more exotic mechanisms. For each category of material, we discuss the dependence of conduction on the morphology of the sample. The presence of heterogeneous disorder is often particularly important in determining the overall behaviour, and can lead to surprisingly similar conduction behaviour in polymers, carbon nanotube networks and chemically-derived graphene (122 references). © 2011 The Royal Society of Chemistry.

Blaikie R.J.,MacDiarmid Institute for Advanced Materials and Nanotechnology
New Journal of Physics | Year: 2010

The prediction of 'perfect' imaging without negative refraction for Maxwell's fish-eye lens (Leonhardt U 2009 New J. Phys. 11 093040) is a consequence of imposing an active localized 'drain' at the image point rather than being a general property of the lens. This work then becomes analogous to other work using time-reversal symmetry and/or structured antennae to achieve super-resolution, which can be applied to many types of imaging system beyond the fish-eye lens. © IOP Publishing Ltd and Deutsche Physikalische Gesellschft.

Lekner J.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2012

We prove that two charged conducting spheres will almost always attract each other at close approach, even when they have like charges. The one exception is when the two spheres have the same charge ratio that they would obtain by being brought into contact. In this case, they repel, and we derive an analytical expression for the force at contact, for any size ratio, generalizing a force formula for equal spheres obtained by Kelvin in 1853. We also give the electrostatic energy of two arbitrarily charged spheres, and its analytical forms at large and small separations. Expressions are derived for the surface charge densities of the two spheres. Attraction occurs between two positively charged spheres because of mutual polarization: one of the spheres obtains a negatively charged region (neighbouring the other sphere). © 2012 The Royal Society.

Olguin J.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Brooker S.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Coordination Chemistry Reviews | Year: 2011

This review begins with a brief introduction to pyrazole and to spin crossover. The focus then moves to a detailed consideration of the synthesis and magnetic properties of structurally characterized iron(II) spin crossover (SCO) active complexes of pyrazole- and pyrazolate-based ligands that also contain at least one pyridine or pyrazine unit within the ligand motif. The syntheses and crystallization methods reported in the original publications are emphasized in this review. The reason for this is that these factors often affect the exact nature of the final product, including the amount and nature of the crystallization solvent molecules present and/or what polymorph is obtained, and hence they can impact strongly on the SCO properties of the resulting materials, as can be seen in this review. © 2010 Elsevier B.V.

Feltham H.L.C.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Brooker S.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Coordination Chemistry Reviews | Year: 2014

A very basic tutorial-style introduction to Single-Molecule Magnetism, intended for a general chemistry audience, is provided. This is followed by a review of the synthesis, structures and magnetic properties of Single-Molecule Magnets (SMMs) that contain just one lanthanide ion and are either (a) monometallic or (b) di- or polymetallic as they also contain one or more transition metal ions (so are heterometallic). We use the term ". monolanthanide" to refer to both. This review covers papers published before July 2013. © 2014 Elsevier B.V.

McVey B.F.P.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Tilley R.D.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Accounts of Chemical Research | Year: 2014

ConspectusUnderstanding and unlocking the potential of semiconductor nanocrystals (NCs) is important for future applications ranging from biomedical imaging contrast agents to the next generation of solar cells and LEDs. Silicon NCs (Si NCs) have key advantages compared with other semiconductor NCs due to silicon"s high natural abundance, low toxicity and strong biocompatibility, and unique size, and surface dependent optical properties. In this Account, we review and discuss the synthesis, surface modification, purification, optical properties, and applications of Si NCs.The synthetic methods used to make Si NCs have improved considerably in the last 5-10 years; highly monodisperse Si NCs can now be produced on the near gram scale. Scaled-up syntheses have allowed scientists to drive further toward the commercial utilization of Si NCs. The synthesis of doped Si NCs, through addition of a simple elemental precursor to a reaction mixture or by the production of a single source precursor, has shown great promise. Doped Si NCs have demonstrated unique or enhanced properties compared with pure Si NCs, for example, magnetism due to the presence of magnetic metals like Fe and Mn. Surface reactions have reached a new level of sophistication where organic (epoxidation and diol formation) and click (thiol based) chemical reactions can be carried out on attached surface molecules. This has led to a wide range of biocompatible functional groups as well as a degree of emission tuneability.The purification of Si NCs has been improved through the use of size separation columns and size selective precipitation. These purification approaches have yielded highly monodisperse and pure Si NCs previously unachieved. This has allowed scientists to study the size and surface dependent properties and toxicity and enabled the use of Si NCs in biomedical applications.The optical properties of Si NCs are complex. Using a combination of characterization techniques, researchers have explored the relation between the optical properties and the size, surface functionalization, and preparation method. This work has led to a greater fundamental understanding of the unique optical properties of Si NCs. Si NCs are being studied for a wide range of important applications, including LEDS with tunable electroluminescence ranging from NIR to yellow, the encapsulation of Si NCs within micelles terminated with proteins to allow targeted in vivo imaging of cells, Si NC-polymer hybrid solar cells, and the use of Si NCs in battery anodes with high theoretical capacity and good charge retention. © 2014 American Chemical Society.

Le Ru E.C.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Etchegoin P.G.,MacDiarmid Institute for Advanced Materials and Nanotechnology
MRS Bulletin | Year: 2013

We provide a review of the main aspects related to surface-enhanced Raman scattering (SERS) enhancement factors (EFs), from their origins to the important issue of their practical quantification. The discussion also focuses on correcting some long-held misconceptions regarding the EFs in SERS, which still persist through the literature. We explain the main topics in simple terms, aiming at clarification of basic concepts rather than an in-depth overview of the already existing literature. © 2013 Materials Research Society.

Le Ru E.C.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Etchegoin P.G.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Annual Review of Physical Chemistry | Year: 2012

A general overview of the field of single-molecule (SM) surface-enhanced Raman spectroscopy (SERS) as it stands today is provided. After years of debates on the basic aspects of SM-SERS, the technique is emerging as a well-established subfield of spectroscopy and SERS. SM-SERS is allowing the observation of subtle spectroscopic phenomena that were not hitherto accessible. Examples of the latter are natural isotopic substitutions in single molecules, observation of the true homogeneous broadening of Raman peaks, Raman excitation profiles of individual molecules, and SM electrochemistry. With background examples of the contributions produced by our group, properly interleaved with results by other practitioners in the field, we present some of the latest developments and promising new leads in this new field of spectroscopy. © Copyright ©2012 by Annual Reviews. All rights reserved.

Brooker S.,MacDiarmid Institute for Advanced Materials and Nanotechnology
Chemical Society Reviews | Year: 2015

The observation of spin crossover with thermal hysteresis loops of more than a few Kelvin remains relatively uncommon and unpredictable, so is a relatively underdeveloped, but important, area of spin crossover, particularly for memory applications. Lessons learnt regarding the origins, and the practicalities of the proper study and reporting, of thermal hysteresis loops are considered and explained, from a synthetic chemists perspective, after a general introduction to the field of spin crossover. This journal is © The Royal Society of Chemistry.

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