UNCOS · Unique Nanocarbons from Critically Opalescent Solutions

Periodic Report Summary 1 - UNCOS (Unique Nanocarbons from Critically Opalescent Solutions)

UNCOS is a 4 year, 0.5 million Euro FP7 IAPP (Industry Academia Partnerships & Pathways) project, coordinated by the University of Brighton. The project draws on and exchanges key expertise between specialists from the Universities of Brighton and Future Carbon GmbH. The aim of UNCOS (http://www.brighton.ac.uk/uncos/) is use of critically opalescent and supercritical carbon dioxide to generate carbon nanomaterials, preferably with defined physicochemical properties and to use these carbons in a variety of applications from automotive industry to composites for biomaterials. It brings together a multidisciplinary group of specialists from different areas of nanotechnology, polymer, physical and analytical chemistry and mechanical and process engineering, working with a common aim of developing new improved materials in a cost-effective process, as well as maintaining a competitive advantage through transfer of knowledge exchanges allowing each workforce the opportunity to benefit from training and development schemes in both academia and industry organisations. Work performed since the beginning of the project has focused on the following key areas of: 1) stability of the critically opalescent CO2 phase over extended periods of time; 2) the reproducible dissociation of critically opalescent CO2 under varying changes of the parameters to control the yield and physicochemical properties of the carbon nanomaterials; 3) increasing the volume of carbon nanomaterial production. Further work in the second phase of the project was to continue research and development in these areas, and also will examine the potential risks (if any) of carbon naomaterials produced and use, and optimisation and scaling up of the production techniques towards real-world application. The project team have worked closely to ensure strong transfer of knowledge between industry and academia, and also with external stakeholders such as carbon nanomaterial production companies and existing technology providers, who have input (via networking and knowledge transfer events held within the UNCOS project at the University of Brighton and during external meetings) key information on industry and performance requirements for carbon nanomaterials. This is to ensure that any prototype testing, characterisation and analytical strategies work themes have been carried out with future project deliverables in mind. In terms of stability of the critically opalescent fluid, this has been successfully for a 10 ml volume reactor charged with carbon dioxide, where opalescence has been observed for greater than 24 hours. This has also been achieved when mixing the critical phase with other materials; though the critical conditions will change slightly, critical opalescence can be re-established. This enabled the system to be doped with potential catalysts and mixing the feedstock. Dissociation of critical carbon dioxide has been achieved, leading to the generation of carbon nanomaterials (mainly hemispheres of carbon on the substrates used, see Fig. 1). However, the yield of carbon production is low and the formation of carbon is not reproducible, despite achieving stable critical opalescence between successive experiments. This has caused a serious impact on the remaining intended work and required greater focus on understanding the lack of reproducibility in order to allow success to obtained for improving yield and scaling carbon production. (SEE ATTACHED FIGURE 1) Fig. 1. Scanning Electron Microscope image of carbon nanoparticles obtained from the UV-laser dissociation of critically opalescent carbon dioxide on the surface of aluminium. Ref: O. Aschenbrenner, et al., “Creation of 3-Dimensional Carbon Nanostructures from UV Irradiation of Carbon Dioxide at Room Temperature”, of Supercritical Fluids, accepted 2012. DOI: http://dx.doi.org/10.1016/j.supflu.2012.07.017 Future work will target the use of supercritical fluids as a medium for the production of carbon nanomaterial. Herein, copolymers based on polyacrylonitrile will be preheated to cause coalescence and expansion through to a carbonized monolith. The resulting monolith will be processed in supercritical carbon dioxide in order to separate out individual layers of graphene. The supercritical fluid will be mixed with appropriate solvents to aid graphene exfoliation. Moreover, the copolymer microstructure will be controlled through adjusting the monomer type and ratio, plus introducing additional molecules to the copolymer mix (prior to carbonization) will aid final separation. This approach lends itself to scalable production of single- and few-layer graphenes. Overall, the project is aimed at producing carbon nanomaterials from carbon dioxide and the significant challenges faced by use of carbon dioxide as a feedstock warrants a broader investigation to use the properties of supercritical carbon dioxide to assist the generation of carbon nanomaterials. For further information, contact the project co-ordinator, Dr Raymond Whitby at the University of Brighton (uncos@brighton.ac.uk).

Data: CORDIS, © European Union