Chairs
Professor Fiona Meldrum, University of Leeds, UK
Professor Fiona Meldrum, University of Leeds, UK
Fiona Meldrum obtained her undergraduate degree from the University of Cambridge in 1989, and her doctorate in biological crystallization from the University of Bath in 1992. Following a postdoctoral position at the University of Syracuse, USA she carried out further postdoctoral work at the Max Plank Institute of Polymerforschung, Germany, before joining the Australian National University in Canberra as a Research Fellow. She returned to the UK to take up a lectureship at Queen Mary, University of London in 1998 and moved to the School of Chemistry, University of Bristol in 2003. She joined the University of Leeds in 2009 where she holds a Chair in Inorganic Chemistry. Her research focuses on crystallization, with particular emphasis on biomineralisation and bio-inspired crystal growth, and includes the major themes of additive-directed crystallisation, effects of confinement and topography on crystallisation, and crystals with composite structures and their structure-property relationships.
09:00-09:45
Clusters, complexes and primary particles in the early stages of bioinspired mineral growth
Professor Nico Sommerdijk, Technische Universiteit Eindhoven, The Netherlands
Abstract
Biominerals possess shapes, structures and properties not found in synthetic minerals. The dream of exploiting the biological principles of controlled mineral formation in materials chemistry inspires a large community to investigate the underlying mechanisms through biomimetic mineralisation experiments.[1] The defining characteristics of biominerals arise from the interplay of the mineral with a macromolecular matrix, which directs crystal nucleation and growth. Within this three dimensional biomolecular assembly, the developing mineral interacts with acidic macromolecules, either dissolved in the crystallisation medium or associated with an insoluble templating structure.[2]
CryoTEM has proven to be a powerful tool to investigate – with great detail – the nucleation and growth of different mineral systems, including calcium carbonate[3], calcium phosphate,[4] iron oxide[5] and silica.[6] It also allows us to study how organic-inorganic interactions at interfaces affect the crystallisation from solution.[7-9] Interestingly we find that all these pathways involve nanometer sized building blocks that have been termed prenucleation clusters,[7-9] prenucleation complexes[4] and primary particles.[5-6] Using time resolved cryoTEM we now also demonstrate how multistep nucleation pathways are altered through the influence of polypeptide based additives.[10] Controlling the pathways of nucleation and growth may help us to ultimately to control the size, shape and orientation of the crystals and optimise them for specific technological applications.[11]
[1] Nudelman and Sommerdijk, Angewandte Chemie-International Edition 2012, 51, 6582.
[2] Chem. Rev. 2008, 108, 4329.
[3] Pouget, et al., J. Am. Chem. Soc. 2010, 132, 11560.
[4] Habraken, et al., Nat. Commun. 2013, 4.
[5] Baumgartner, et al., Nat. Mater. 2013, 12, 310.
[6] Carcouet, et al., Nano Lett. 2014, 14, 1433.
[7] Pouget, et al., Science 2009, 323, 1455.
[8] Dey, et al., Nat. Mater. 2010, 9, 1010.
[9] Nudelman, et al., Nat. Mater. 2010, 9, 1004.
[10] Dey, et al., Faraday Discuss. 2015, 179, 215.
[11] De Yoreo, et al., Science 2015, 349, 498.
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Professor Nico Sommerdijk, Technische Universiteit Eindhoven, The Netherlands
Professor Nico Sommerdijk, Technische Universiteit Eindhoven, The Netherlands
Nico Sommerdijk is full professor at Eindhoven University of Technology and head of the Laboratory of Materials and Interface Chemistry. In 1995 he obtained his PhD (Cum Laude) from the University of Nijmegen for his work on chiral amphiphiles. He did postdoctoral work on sol-gel silicates (1995-1997, University of Kent-UK), on bio-inspired crystallisation (1997, Keele University-UK) and on macromolecular self-assembly (1997-1998, Nijmegen-NL). In 1999 he moved to Eindhoven to work on bio-inspired hybrid materials through biomimetic mineralisation and self- organisation. He studies these processes combining (macro)molecular self-assembly and advanced electron microscopy. Professor Sommerdijk’s work has been supported by VIDI and VICI Awards from the Netherlands Science Foundation, and he is winner of the RSC Soft Matter and Biophysics Award 2015. He is director of Centre of Multiscale Electron Microscopy , core member of the Institute for Complex Molecular Systems, and member of the Eindhoven Polymer Laboratories and the Eindhoven Multiscale Institute.
09:45-10:30
Challenges for the simulation of nucleation pathways for biominerals
Professor Julian Gale, Curtin University, Australia
Abstract
The nucleation of biominerals, such as calcium carbonate and calcium phosphate, has attracted significant attention in the last decade following the proposal of so-called 'non-classical' mechanisms. For the case of calcium carbonate it has been proposed that the pathway to formation under homogeneous conditions can include stable pre-nucleation clusters (PNCs) [1], liquid-liquid phase separation [2] and the formation of amorphous calcium carbonate as a thermodynamically stable phase for nanoparticles in a given size range [3]. Given the difficulties of probing such species in situ with experimental techniques, atomistic simulation is a valuable complementary approach. However, simulation faces a number of challenges of it’s own due to the limitations of molecular dynamics with the currently available computing power. For example, the concentrations of ions at saturation for most biominerals are below 1 mM, meaning that unbiased sampling of ion association in aqueous solution at experimental conditions is unfeasible. In this presentation several challenges for simulation of ion association from ion pairing, through pre-nucleation species, to determining critical nucleus size will be examined. This includes issues spanning the underlying accuracy of the free energy landscape through to how to map cluster stability in terms of a manageable set of collective variables that capture the association/dissociation pathways and connect them to identifiable thermodynamic states. Here examples will be drawn from aqueous calcium systems with carbonate, phosphate and oxalate.
[1] D. Gebauer et al, Science, 322, 1819 (2008)
[2] A.F. Wallace et al, Science, 341, 885 (2013)
[3] P. Raiteri & J.D. Gale, J. Am. Chem. Soc., 132, 17623 (2010)
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Professor Julian Gale, Curtin University, Australia
Professor Julian Gale, Curtin University, Australia
Professor Julian Gale obtained his first degree from the University of Oxford in Natural Sciences (Chemistry), where he continued on to study for a DPhil in the Department of Chemical Crystallography. After a postdoctoral position at the Royal Institution of Great Britain he moved to Imperial College London as a Royal Society University Research Fellow and subsequently Reader in Theoretical and Computational Chemistry. In 2003 he moved to his current location, Curtin University, as a Premier’s Research Fellow and now holds the position of John Curtin Distinguished Professor of Computational Chemistry. Research interests include the development and application of computational techniques to problems in areas including materials science, geochemistry and mineralogy.
11:00-11:45
Nucleation and growth processes of gas clathrate hydrates
Professor Carolyn Ann Koh, Colorado School of Mines, USA
Abstract
Gas clathrate hydrates are crystalline inclusion compounds comprised of a three-dimensional network of hydrogen-bonded water molecules that can trap small gas molecules in the water cavities. The ability to control clathrate hydrate nucleation and growth processes is important in several energy applications, including during the production and transportation of oil/gas in subsea flowlines where gas hydrates can form blockages in the flowline, as well as energy storage of fuels in gas hydrate crystals. The nucleation and growth processes and inter-particle interactions of gas hydrate crystals on gas bubbles and water droplets in water and oil continuous systems are examined at high pressure and low temperature conditions. Addition of polymers and surface-active molecules can be used to modify these processes, e.g. delaying the nucleation and growth processes, or reducing the inter-particle interactions. The clathrate hydrate formation synthesis pathways can be a key strategy to designing higher storage capacity materials, and/or stabilising new stable and metastable crystal structures. Structure metastability has been observed through spectroscopic and computational studies. Examples of the use of different promoter guest molecules, synthesis methods, and pressure conditions are presented for the production of stable and metastable clathrate hydrate phases. These studies can help further our knowledge for developing clathrate materials for storage and other technologies.
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Professor Carolyn Ann Koh, Colorado School of Mines, USA
Professor Carolyn Ann Koh, Colorado School of Mines, USA
Carolyn A. Koh is Professor of Chemical and Biological Engineering and Director of the Center for Hydrate Research at the Colorado School of Mines (CSM). She obtained her BSc (Hons) and PhD degrees from University of West London and postdoctoral training at Cornell University. She was a Reader at King’s College, London before joining the Colorado School of Mines. She has been visiting Professor at Cornell, Penn State and London University. She was a consultant for the Gas Research Institute in Chicago and is a Fellow of the Royal Society of Chemistry, Associate Editor of the Society for Petroleum Engineers Journal, a member of the Editorial Advisory Board of the ACS J. Chem. Eng. Data, US DOE Methane Hydrate Advisory Committee member, and served on the National Academies NRC committee assessing the US DOE National Methane Hydrate Program. She is also an active member of the joint ASME-AIChE Committee on Thermophysical Properties and organised/chaired/co-chaired sessions of the joint ASME-AIChE Thermophysical Properties Conferences. She has been elected co-Chair and Chair of the Gordon Research Conferences on Gas Hydrates in 2016 and 2018, respectively. She has established internationally recognized gas hydrate research programs over the last two decades at King’s College, University of London and the Colorado School of Mines. Her research is focused on understanding the nucleation, crystallisation and inhibition mechanisms and thermophysical properties of natural gas hydrates. She was awarded the Young Scientist Award of the British Association for Crystal Growth, the CSM Outstanding Faculty Member Award, Senior Class (2013) and Young Faculty Research Excellence Award (2012). She has over 140 publications in refereed journals, including Science, Physics Today, J. American Chemical Society, and two books, including Clathrate Hydrates of Natural Gases (the “third edition of a best seller” – quote from CRC Press publishers, co-authored with E.D. Sloan).
11:45-12:30
Free energy landscape and molecular pathways of ice and gas hydrate nucleation
Professor Tianshu Li, George Washington University, USA
Abstract
Gas hydrate and ice are similar in many aspects: both appear 'ice-like', and both form in aqueous environments as a result of ordering of water molecules. However the nucleation processes of two solids could proceed with very different pathways. Employing advanced molecular simulation methods, this talk explores the free energy landscape and molecular pathways of both ice and hydrate nucleation. This talk shows that ice nucleation, both homogeneous and heterogeneous, appears to follow a pathway described very well by classical nucleation theory (CNT). The nucleation of hydrate, on the other hand, has been often found to involve multiple steps, thus appearing non-classical. Indeed, structural analysis show that on average, hydrate formation is facilitated by a 'two-step' like mechanism involving a gradual transition from amorphous to crystalline structure. However analysis also shows the existence of direct nucleation pathways where hydrate crystallises without going through the amorphous stage. Interestingly, the calculated free energy profile was also found to fit reasonably well against CNT. The structural diversity and the CNT-like free energy profile imply that hydrate nucleation could be an entropically driven, kinetic process that proceeds via multiple pathways that have similar free energy profiles.
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Professor Tianshu Li, George Washington University, USA
Professor Tianshu Li, George Washington University, USA
Tianshu Li received his PhD in Materials Science from University of California, Berkeley in 2005. From 2006 to 2010, he continued his research as a post-doctoral scientist in Professor Giulia Galli’s group at University of California, Davis. He then joined the faculty of civil and environmental engineering department at the George Washington University in 2010. One of his main research interests is to understand nucleation process through molecular modelling, with current focus on ice and clathrate hydrate. Besides nucleation, his group is also interested in low-dimensional materials and energy materials under extreme conditions.