25 May 2017: Rob Atkins

Thu 25 May 2017 3:30pm (Murdoch University, ECL Postgraduate Suite, 460.2.031)

Structure, Solutes and Surfaces in Ionic Liquids

Rob Atkin

School of Molecular Sciences, The University of Western Australia, WA 6009, Australia

Ionic Liquids (ILs) are a subset of molten salts, distinguished by having melting points below 100 °C. Their low melting points are brought about by weakening electrostatic interactions between the ions and hindering their packing into a crystal lattice. Electrostatic forces are reduced by engineering their molecular structure so that at least one of the ions is large and organic, which increases the distance between neighbouring charged centres, and by delocalising the ionic charge over a large molecular volume. Ionic liquids have some unusual and remarkable properties, including pronounced nanostructures, which is one of their unique, yet unifying, characteristicss.

Neutron diffraction measurements modelled with reverse Monte Carlo simulations will be used to show that ILs have a sponge-like (bicontinuous) nanostructure; IL cation alkyl chains and ionic groups are segregated into domains that percolate throughout the bulk liquid.1-3 A snapshot of the simulation box for ethylammonium nitrate (EAN, a protic IL) is shown in Figure 1 (left). Varying the structure of the ions changes way inter-ionic forces are expressed, which leads to changes in nanostructure. The effect of dissolved water, glycerol and octanol on bulk IL nanostructure will be examined.4,5

High resolution amplitude modulated atomic force microscope images (c.f. Figure 1) will be used to demonstrate how IL nanostructure changes at a solid surface with the ion structure, and the effect of dissolved solutes.6-8 A 20 nm × 20 nm topographic AM-AFM images of the 1-Ethyl-3-methylimidazolium bis(trifluoromethyl- sulfonyl) imide – graphite Stern layer is shown in Figure 1 (middle), with the position of the ions shown in the magnified area in Figure 1 (right). The effect of applying a potential to a conducting solid surface on the IL interfacial nanostructure will also be discussed, and recent results for the spontaneous exfoliation of graphene into an ionic liquid will be described.9

Figure 1. (left) Snap shot of simulation box used to fit neutron diffraction data for EAN. (middle and right) AM-AFM image of the 1-Ethyl-3-methylimidazolium bis(trifluoromethyl- sulfonyl) imide – graphite Stern layer.

References

(1) Atkin, R.; Warr, G. G. J. Phys. Chem. B 2008, 112, 4164.

(2) Hayes, R.; Imberti, S.; Warr, G. G.; Atkin, R. Physical Chemistry Chemical Physics 2011, 13, 3237.

(3) Hayes, R.; Imberti, S.; Warr, G. G.; Atkin, R. Angewandte Chemie International Edition 2013, 52, 4623.

(4) Hayes, R.; Imberti, S.; Warr, G. G.; Atkin, R. Angewandte Chemie International Edition 2012, 51, 7468.

(5) Murphy, T.; Hayes, R.; Imberti, S.; Warr, G. G.; Atkin, R. Physical Chemistry Chemical Physics 2014, 16, 13182.

(6) Elbourne, A.; Voitchovsky, K.; Warr, G. G.; Atkin, R. Chemical Science 2015, 6, 527.

(7) Page, A. J.; Elbourne, A.; Stefanovic, R.; Addicoat, M. A.; Warr, G. G.; Voitchovsky, K.; Atkin, R. Nanoscale 2014, 6, 8100.

(8) Elbourne, A.; McDonald, S.; Voïchovsky, K.; Endres, F.; Warr, G. G.; Atkin, R. ACS Nano 2015, 9, 7608.

(9) Elnourne, A.; Mclean, B. D.; Voïchovsky, K.; Warr, G. G.; Atkin, R J. Phys. Chem. Lett., 2016, 7, 3118

 

Rob Atkin is a Professor of Chemistry at the University of Western Australia. Rob obtained his PhD from the University of Newcastle (Australia) in 2003 under the supervision of Prof Simon Biggs, then joined the group of Prof. Brian Vincent at Bristol University as a postdoctoral fellow, working on polymer microencapsulation. In 2005 he was awarded an Australian Research Council (ARC) Postdoctoral Fellowship to study surfactant self-assembly in ionic liquids at the University of Sydney in collaboration with Prof Greg Warr. He returned to Newcastle in 2007 as a University of Newcastle Research Fellow, was awarded an ARC Future Fellowship in 2012, and promoted to Professor in 2015. In March 2017 Rob moved to his current position at the University of Western Australia. Rob has published 6 book chapters and 130 journal articles and collaborates with groups in Australia and in the UK, Sweden, Germany, the USA, Japan and France.

18 Feb 2016 : Jacob Kirkensgaard

Complex self-assembly morphologies of multicomponent miktoarm star copolymers

Speaker : Dr Jacob Kirkensgaard – University of Copenhagen
Date       : 18 Feb 2016, 4:15pm  (Murdoch University, ECL2.031)
The self-assembly morphologies of various complex architectured miktoarm star copolymers consisting of more than two components has been investigated using dissipative particle dynamics simulations. The star topology of such molecules allow a wealth of new structures to be controllably realized as a function of composition, interaction parameters and molecular architecture. Here a number of highlights are presented showing many novel kaleidoscopic morphologies, including 2D tiling patters and 3D networks many of which show hierarchical features, i.e. ordering on multiple length scales. Several examples are extensions of the well-known bicontinuous structures P, D and G found in many natural and synthetic two-component systems.

31 Mar 2016: Paul Dalton

3D Printing of High Fidelity Tissue Engineering Scaffolds

Speaker   : Prof Paul Dalton – Würzburg University / Germany

Venue      : 31 March 2016 @ 15:00  (Murdoch University, Senate Conference Room)

Considering the complexity of the structure and the organization of the natural tissues, a major challenge in tissue engineering applications is to produce three-dimensional (3D) structures that are anatomically accurate. Consequently, there has been a significant effort in developing techniques to manufacture substrates with a defined organization, however resolutions remain limited. Melt electrospinning writing is an additive manufacturing process that electrostatically stabilizes a molten thread, placing it accurately onto a collector. It can generate organized 3D scaffolds with a precise and predictable layer-by-layer deposition with finely resolved fibers. This solvent-free approach provides a pathways to clinical products while addressing the need for 3D architecture requirements for a variety of tissue engineering applications.

Biography: Paul Dalton is a Professor in Biofabrication at the University of Würzburg, Germany. He has 20 years’ of interdisciplinary experie2016_03_31_PaulDaltonBionce in biomedical materials, including polymer processing, surgery, nanotechnology and surface science. Originally from Perth, Australia, and trained as a materials scientist, he was part of a successful team in the 1990s taking an artificial cornea from concept to the clinic. Paul post-docced at the University of Toronto, Canada, and RWTH Aachen, Germany, working in neural tissue engineering and applying nanotechnology to life science applications. As an independent fellow at the University of Southampton, he invented melt electrospinning writing as a new 3D printing technology and performed experimental surgery to understand the neuroinflammation of hydrogels in the spinal cord. Between 2010 and 2013, he split his time between Shanghai Jiao Tong University in China and Queensland University of Technology in Australia. Paul has an H-Index of 36 from only 70 research articles published in journals including Advanced Materials, Progress in Polymer Science, Nature Communications and Nature Materials.