High pressure chemistry of solids and liquids

Lead Research Organisation: University College London
Department Name: Chemistry

Abstract

We will explore new solid state chemistries occurring under extreme conditions of high pressure and high temperature, combining high-pressure synthesis in large-volume devices with in situ studies in the diamond anvil cell. We will focus our studies on developing the solid state chemistry of new light element , compounds, based on C, O, N, H, B etc. , These usually provide molecular gases, liquids and organic compounds, but they also give rise to superhard solids like diamond and cubic boron nitride. We will also explore metastable thermodynamic pathways to new materials prepared under high-pressure conditions, combining chemical precursor routes to yield unusual new compounds and materials, and metastable compression/decompression strategies to tune the properties of the resulting materials. We will study the physical chemistry of liquids and glasses at high pressure, to explore the new phenomena of density-driven phase transitions and polyamorphism that are reported to occur in liquids and glasses at constant chemical composition. This is a new area in the physical science of liquids that needs to be explored and developed.

Publications

10 25 50
 
Description We investigated synthesis of new nitride materials from chemical precursor routes using high pressure-high temperature approaches. We discovered a new carbon nitride hydride compound C2N3H that was recoverable to room pressure : this is the first example of a series of new dense light element phases. We produced titanium nitride amorphous-crystalline nanocomposites and tested their mechanical properties. These did not have high hardness as expected but showed signs of unusual brittle-ductile behaviour under applied load. We investigated high pressure structures and phase transitions in oxide pyrochlores to understand their dielectric properties and in photocatalytically active titanium oxonitride. We adapted our high pressure techniques to form polycrystalline discs of TiO2 for photocatalytic testing, and developed new encapsulation in Teflon containers for experiments to introduce and trap Cs+ ions inside zeolites. That work has implications for radioactive waste immobilisation. We also investigated the high pressure structural behaviour and amorphisation of zirconolite that is proposed as a refractory ceramic radionuclide host. We investigated pressure-induced amorphous-amorphous phase transitions between glasses and liquids with different density. That constitutes a new branch of physical chemistry research. We investigated the formation and recovery of high-density metallic and superconducting forms of amorphous silicon and germanium, and the emergence of a low density "polyamorph" of glassy yttria-alumina mixtures following a liquid-liquid phase transition. That project is leading to creation of new ceramic/matrix nanocomposite materials. We used the EPSRC Senior Research Fellowship to open up new areas in high pressure biology and biophysics as well as soft matter studies. We Investigated the mechanical properties of cellulose resolving a long-standing issue between compression resistance along and between the chains, and studied amyloid fibrils compressed in different media to help distinguish between different structural models. We used our new Teflon high pressure cells developed for the Cs incorporation study to begin new investigations of bacterial survival into the GigaPascal range, long thought to be impossible. Our first results showed existence of E. coli populations to at least 2 GPa following sequential cloning of pressure-adapted survivors. We also applied our facilities and expertise to investigate Raman and fluorescence spectroscopy applied to collagen and cartilage samples, and developed a new methodology for investigation of early cartilage disease. Likewise we brought the fibre-optic and microbeam Raman techniques to bear on operando and in situ studies of catalysis in microchannel flow conditions. These "spin-out" activities are now incorporated in other projects including commercial development.
Exploitation Route The new high pressure materials especially nitrides have potential applications in photocatalysis and other optoelectronic device applications : however the research results are still highly "upstream" and need more fundamental research and development to achieve potentially useful technology.



The work on liquid-liquid phase transitions and polyamorphism can lead to new generations of nanocomposite materials with designed mechanical and thermal properties. We are exploring this for ceramic aluminate-silicate-phosphate systems with colleagues in the USA.



The new area of high pressure biology can have major implications for bionanotechnology in areas ranging from environmental remediation, food processing to electrically conducting nanonetworks and nanomaterials fabrication. We are currently exploring these possible extensions of our research.



Our experience and expertise with optical spectroscopy along with high pressure techniques is leading to potentially new biomedical applications such as the patented process for cartilage disease detection. Our main route is via UCL Business that provides advice and support for developing patenting and licensing strategies, and interactions with potential industry partners and other institutions. We also seek to develop personal contacts and interactions with potential collaborators and development partners both informally and at organised workshops, seminars and conferences. Another main exploitation avenue for the research is in outreach to public/schools audiences, that we participate in regularly mainly through both organised talks and conference programmes and individually organised presentations.
Sectors Chemicals,Education,Energy,Environment,Healthcare

 
Description The award was designed to explore the chemistry and physical properties of new solids, liquids and amorphous materials under high pressure conditions. In the area of high pressure chemistry we developed new approaches based on combining designed chemical precursors with high pressure-high temperature treatment to achieve new nitrides and other materials, some have which have potential for future technological development. The techniques developed by our group are now being implemented in other research studies in the UK and internationally. Our work on liquids and solid amorphous materials has established a firm foundation for the new physical phenomena of liquid-liquid phase transitions and polyamorphism driven by the density rather than chemical composition. The outcomes at present are mainly academic but there could be technological potential development for creation of novel nanocomposite materials. Finally the new techniques and approaches allowed us to develop first studies in new areas of high pressure biophysics, soft matter research and experimental biology, as part of a rapidly emerging new field to understand the structure and function of biologically important macromolecules and organisms under extreme conditions. results have inspired others to follow similar approaches to discover new materials and physical phenomena. They have allowed us to initiate new fields of research in high pressure biology and biophysics studies.
First Year Of Impact 2003
Sector Chemicals,Education,Energy
Impact Types Societal,Economic

 
Description AWE
Amount £1,029,248 (GBP)
Funding ID Enhancement of AWEs hydrodynamics science capability 
Organisation Atomic Weapons Establishment 
Sector Private
Country United Kingdom
Start 06/2008 
End 06/2013
 
Description Leverhulme Research grant scheme
Amount £164,159 (GBP)
Funding ID RPG-350 
Organisation The Leverhulme Trust 
Sector Academic/University
Country United Kingdom
Start 02/2012 
End 09/2015
 
Description Materials Innovation Impact Acceleration
Amount £40,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 05/2014 
End 04/2015
 
Title Electrode for use in a lithum-ion electrochemical cell 
Description Carbon nitride materials to be developed for use a lithium ion battery electrodes 
IP Reference GB1311742.9 
Protection Patent application published
Year Protection Granted 2013
Licensed No
Impact None to date
 
Title Tissue assessment 
Description A method to evaluate cartilage disease grade using Raman spectroscopy. 
IP Reference GB0808711.6 
Protection Patent granted
Year Protection Granted 2009
Licensed No
Impact The application has been tested in vivo but no partners have expressed interest to date.
 
Description Schools and public lectures 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Presentations including demonstration lectures about materials chemistry, high pressure science, glasses and amorphous materials to schools and general public audiences, throughout the UK, in France and the USA
Year(s) Of Engagement Activity Pre-2006,2006,2007,2008,