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WW8.05/AAA10.05 - Thermo-Mechanical Behaviour of Polymer Nanocomposites Examined by In-situ near Edge X-Ray Absorption Fine Structure Spectroscopy 
April 24, 2014   4:15pm - 4:30pm

The extraordinary mechanical, thermal, electronic and optical properties of carbon nanotubes (CNTs) have garnered considerable interest in a wide range of academic fields. CNTs are attractive candidates as fillers in composite materials, considerably improving the properties of the host. Recently, vast research has been undertaken to investigate the active properties of some polymer-CNT composites, with potential applications ranging from Micro-opto-electro-mechanical systems (MOEMS) to neuroscience. The development of this field is hindered, however, as the mechanics of actuation at the molecular level in these composites is still not well understood and a unified model explaining this behaviour is missing. Consequently, there is no method to predict whether specific materials exhibit this “smart behaviour”.Near edge X-ray absorption fine structure (NEXAFS) spectroscopy is a valuable synchrotron technique for the study of nanocomposites, offering a wealth of information about local chemistry of the system, all with excellent energy resolution. Additionally, the use of a highly polarized beam allows for assessment of conformational arrangement of soft matter, which is of critical importance when the system is governed by non-covalent interactions.In this study, films of thermally active EVA|MWCNT composites are studied through in-situ NEXAFS spectroscopy in an attempt to correlate spectral progression of the system with macroscopic observations of mechanical actuation. The effects of straining to promote CNT alignment and the role of dispersants are also addressed. Systematic variations in NEXAFS spectra with increasing temperature identify emissions from specific chemical groups as possible actors in the actuation mechanism, and suggest a high degree of conformational effects. An actuation model based on molecular orientation is later proposed which supports our findings. These are the initial steps towards forming a systematic database aiming at active behaviour prediction of polymer nanocomposites, and the production of materials by design.

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Keynote Address
Panel Discussion - Different Approaches to Commercializing Materials Research
Business Challenges to Starting a Materials-Based Company
Fred Kavli Distinguished Lectureship in Nanoscience
Application of In-situ X-ray Absorption, Emission and Powder Diffraction Studies in Nanomaterials Research - From the Design of an In-situ Experiment to Data Analysis