Final Activity Report Summary - YURICO (Synthesis, chemical functionalisation, modification, and applications of nanodiamonds and carbon onions) Nanodiamond powder, produced by the detonation of explosives is a widely available material. It consists of nanodiamond crystallites with a very narrow size distribution (2-20 nm). However, their exploitation in different fields is strongly limited due to their tight aggregation during synthesis. Results of our work have shown that atomic hydrogen treatments upon nanodiamond surfaces can be successfully used to not only to deaggregate nanodiamonds but also to produce hydrogen terminated nanodiamonds. The relative chemical inertness of carbon-hydrogen bonds hinders the formation of chemical bonding between hydrogenated nanodiamond crystallites, and therefore prevents their reaggregation. An alternative technique based on mechanically activated chemical functionalisation of nanodiamonds has been shown to be very successful for deaggregation and passivation of diamond nanocrystalltes. Additionally, several techniques for controllable chemical nanodiamond functionalisation and attachment of nanodiamond monolayers to gold surface have been developed during the project.The developed techniques of deaggregation and chemical functionalisation of nanodiamonds give wide possibilities for development of their industrial applications in electronics, medicine and for designing of new materials: a combination of lithography techniques and attachment of nanodiamonds to gold surfaces will allow diamond nanocrystallites to be precisely positioned in desired places and therefore allow nanodiamond crystallites to be used as building blocks for new electronic or mechanical devices; functional groups on nanodiamond surfaces can be used for attachment of biologically active molecules (proteins, DNA) and therefore enable development of new drug delivery systems; attached functional groups can serve as bridges between nanodiamond crystallites to other nanoparticles or polymer molecules and therefore can be used for development of new composite and polymer materials. We have also found that detonation nanodiamonds contain nitrogen as substitutional atoms which act as a donor centres and modify the electronic and optical properties of the diamond crystallites and could give origin to the blue luminescence from nanodiamonds, which can be utilised for an in-vivo imaging technique. Investigation of nanodiamond properties is of interest not only for its practical implications, but also because they can help solve important theoretical problems related to the thermodynamical stability of diamond crystals at nanoscale dimensions and in the origin of nanodiamonds in the interstellar media.Carbon onions consist of fullerene-like shells enclosed within one another (multishell fullerenes). Carbon onions have fascinating properties, due to their highly symmetric structure. In the project the onion-like carbon (OLC) consisting of aggregates of carbon onions was synthesised via annealing of nanodiamonds. Fullerene-like shells in initial OLC are closed. To develop surface area of OLC a technique of 'carbon onion opening' has been developed. Since sizes of carbon onions, number of their fullerene-like shells and diameter of the internal shell in carbon onions can be controlled by the sizes of initial diamond nanocrystallites and by the variation of annealing temperatures, this technique can be used as a method to prepare a variety of carbon nanocapsules for different substances. Since the process of the opening of carbon onions is performed separately from their filling, a wide range of filling substances can be used. During the project OLC have been proposed as catalysts for styrene synthesis by oxidative dehydrogenation of ethylbenzene and as a model system for investigations of carbon nanoparticles in interstellar media and for carbon air pollutants in cities.
