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Full-Text Articles in Physical Sciences and Mathematics

Synthesis, Characterization, And Application Of Ag Nanostructures, Stephen Hudson Dec 2008

Synthesis, Characterization, And Application Of Ag Nanostructures, Stephen Hudson

All Dissertations

Noble metal nanoparticles (NPs) have been used for many centuries; however their properties were not truly scrutinized until Michael Farady's investigations in the 1850's. Advances in the field of nanotechnology over the last three decades have enabled insights into the properties of materials as their dimensions are reduced to the nanoscale. The repercussions of these insights are seen in many modern applications.
In this dissertation, properties of novel nanostructures based on Ag NPs are presented and discussed. The exceptional optical properties of Ag NPs stem from the collective oscillations of the conduction electrons known as plasmon resonances. The excitation of …


Molecular Nanoscience And Engineering On Surfaces, Willi Auwarter, Agustin Schiffrin, Alexander Weber-Bargioni, Yan Pennec, Andreas Riemann, Johannes V. Barth Sep 2008

Molecular Nanoscience And Engineering On Surfaces, Willi Auwarter, Agustin Schiffrin, Alexander Weber-Bargioni, Yan Pennec, Andreas Riemann, Johannes V. Barth

Physics & Astronomy

Molecular engineering of low-dimensional materials exploiting controlled self-assembly and positioning of individual atoms or molecules at surfaces opens up new pathways to control matter at the nanoscale. Our research thus focuses on the study of functional molecules and supramolecular architectures on metal substrates. As principal experimental tools we employ low-temperature scanning tunneling microscopy and spectroscopy. Here we review recent studies in our lab at UBC: Controlled manipulation of single CO molecules, self-assembled biomolecular nanogratings on Ag(111) and their use for electron confinement, as well as the organisation, conformation, metalation and electronic structure of adsorbed porphyrins.


Metallomesogens: Supramolecular Design Via Alkyl-Rich Metal Complexes, Juan C. Noveron Sep 2008

Metallomesogens: Supramolecular Design Via Alkyl-Rich Metal Complexes, Juan C. Noveron

Juan C N

Molecules that use non-covalent interactions to self-organize into supramolecular structures have the potential to generate functional materials with a broad range of applications. This review article focuses on the design and synthesis of molecules that use transition metal ions and long alkyl chains to direct the formation of ordered supramolecular phases. This unique combination of coordination bonds and alkyl interdigitation provide exceptional control over intermolecular interactions and can generate nanoscale molecular order as liquid crystalline states, Langmuir-Blodgett films on surfaces, highly ordered lyotropic phases such as metallo-micelles in water and reverse metallo-micelles in organic media. The synthetic strategy for alkane-rich …


A Selectivity Study On The Use Of Caffeine And Theobromine Imprinted Polypyrrole Surface Electrodes, Anil Kiran Kumar Vinjamuri Aug 2008

A Selectivity Study On The Use Of Caffeine And Theobromine Imprinted Polypyrrole Surface Electrodes, Anil Kiran Kumar Vinjamuri

Masters Theses & Specialist Projects

Molecularly imprinted polymers (MIPs) are proving to be very effective in development of synthetic recognition systems and are of great interest to those interested in the field of sensor technology. The use of MIPs is receiving considerable interest due to the ability to prepare recognition matrices that possess high substrate selectivity and specificity. Conducting polymers (CP) have proved to be an excellent tool for the preparation of nano-structured biologically selective systems. Polypyrrole (Ppy) is one such CP that is extensively used for the construction of bioanalytical sensors. Ppy has shown great promise primarily due to its biocompatibility and thermal stability …


Structural Identification Of Cubic Iron-Oxide Nanocrystal Mixtures: X-Ray Powder Diffraction Versus Quasi-Kinematic Transmission Electron Microscopy, Peter Moeck Mar 2008

Structural Identification Of Cubic Iron-Oxide Nanocrystal Mixtures: X-Ray Powder Diffraction Versus Quasi-Kinematic Transmission Electron Microscopy, Peter Moeck

Physics Faculty Publications and Presentations

Two novel (and proprietary) strategies for the structural identification of a nanocrystal from either a single high-resolution (HR) transmission electron microscopy (TEM) image or a single precession electron diffraction pattern are proposed and their advantages discussed in comparison to structural fingerprinting from powder X-ray diffraction patterns. Simulations for cubic magnetite and maghemite nanocrystals are used as examples.


Contextualising Nanotechnology In Chemistry Education, Christine O'Connor, Hugh Hayden Jan 2008

Contextualising Nanotechnology In Chemistry Education, Christine O'Connor, Hugh Hayden

Articles

This paper will give an example of a pedagogical approach taken in integrating nanotechnology into a chemistry degree course. In recent years nanotechnology has widely become part of the course content for undergraduate chemistry and physics degree curriculum. How contextualised the delivery of the subject matter may vary. The role of contextualisation of nanotechnology in the delivery of the content is the main focus of this paper, as to date in Ireland and many other countries nanotechnology has not been integrated into many chemistry degree courses but is slowly becoming the case. An evaluative methodology of the pedagogical approach for …


Hydrogels Of Versatile Size And Architecture For Effective Environmental Applications, Nurettin Sahiner Jan 2008

Hydrogels Of Versatile Size And Architecture For Effective Environmental Applications, Nurettin Sahiner

Turkish Journal of Chemistry

Cationic hydrogels from a positively charged monomer, (3-Acrylamidopropyl)-trimethylammonium chloride (APTMACl), were synthesized as bulk, and micro- and nano-sizes. These hydrogels were utilized to remove contaminants such as food dyes and an environmentally toxic metal, arsenic. The micro- and nanohydrogels were dispersed in another hydrogel network to design a semi-interpenetrating network (semi-IPN) which was shown to visualize the particles that can be used for absorption purposes. The micron-sized cationic hydrogel particles were very effective in the removal of arsenic from an aqueous environment- 96% of the arsenic was removed in less than 10 min from a 55-ppm aqueous stock solution. Cationic …


High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi Jan 2008

High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi

Faculty Publications

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the …