- Email: [email protected]
The Australian national university, Canberra, ACT
835
epitaxiality (i.e. axis relations?) has not been The integrity of the carbon capsule established. produces remarkable resistance of the aerosol towards ambient oxidation of the metal, a surprising result given the extremely high surface-area-to-volume ratio of the population of tiny platelets and the susceptibility of most if not all of these metals to oxidation by air. Capsule integrity is also graphically illustrated by the resilience of a mercury fulleroid under the high vacuum Electron-beam heating while of a TEM column. imaging in the Hg case leads to some fascinating microstructures as the liquid metal separates from the carbon shell and agglomerates with nearby droplets. (T. J. Senden, K. H. Moock, J. D. FitzGerald, W. M. Burch, R. D. Browitt, C. D. Ling, and G. A. Heath) Faculty of Engineering
and Information
Technoloav
We have previously studied in detail the quantitative kinetics of the chemical cross-linking reactions in epoxy resins, and the phase separation in modified resins during the curing process. Presently we are extending these studies to include a third phase, namely highlyoriented pyrolitic graphite (HOPG). Preliminary results indicate that the curing of the resins in contact with the HOPG (0002) basal plane causes depletion of the segregated (particulate) phase in the region within 100 microns of the epoxy-HOPG interface. The next step is investigation of the effects that could arise when curing on interfaces that are oriented perpendicular to (0002) of HOPG. A study of the microstructure of the HOPG reveals plate-shaped domains of near perfect threedimensional graphite crystal stucture, extending approximately 100 mn perpendicular to the basal planes, but tens of microns or more in the graphite plane. All domains share a common (0002) orientation, but the crystal axes are misoriented at every domain boundary. Some of the domain boundaries appear to have parted slightly and now exist as microcracks. In bonding of epoxy onto a macroscopic HOPG face perpendicular to (0002), atomic configuration at the interface could therefore be changing on the 100 nm scale due to the presence of domains and domain boundaries. The group continues studies of the interlaminar strength between carbon fibres and polymer matrix, in particular in relation to marine environment. This year the first prepregging laboratory in Australia for advanced composite materials will be made operational with the installation of a WEB drum winder with high temperature capability, a twin screw extruder, and a high temperature/high pressure autoclave. (Zbigniew
Stachurski)
Research School of Chemistry Professor J. W. White and co-workers have completed a number of projects, mainly relating to superconductivity and fullerenes. Topics include the following:
Structures of ammoniated A$,, superconductors (R. J. N. Durand, W. K. Fullagar, G. A. Lindsell, P. A. Reynolds, J. W. White). Superconductivity measurement W. K. Fullagar, J. W. White).
- (R.
Bramley,
Low temperature gas intercalation in alkali graphite intercalates - (G. A. Lindsell, G. Lockhart, P. A. Reynolds, J. W. White). Inelastic neutron scattering and superconductivity of Rb,C,,(NH,)x - (C. J. Carlile, R. J. N. Durand, W. K. Fullagar, P. A. Reynolds, F. Trouw). Structures and vibrations of alkali metal fullerides (W. K. Fullagar, P. A. Reynolds, J. W. White).
-
Vibronically resolved absorption spectra in C,, anions - (W. K. Fullagar, J. W. White, G. Heath). Low temperature gas intercalation in alkali graphite intercalates - (G. A. Lindsell, P. A. Reynolds, J. W. White). Research School of Earth Sciences The main topic of research has been the interaction of mesophase with metal surfaces. For example, under particular conditions, mesophase readily wets and coats the surface of a copper plate, whereas an aluminium plate does not wet. The nature of the surface interactions is being investigated with emphasis on the true nature of the interface-whether there is an oxide or other film, for example. (A. Lee, G. H. Taylor) Research School of Phvsical Sciences and Engineering A new defect-based model for the growth of the fullerene molecule, C,,, assembling from a hot, homogeneous and dense ensemble of carbon atoms, or ‘primeval soup,’ has been presented in a paper entitled “Fullerene genesis by ion beams II: Disclinations and the corranulene road.” Routes, comprising swift open channels to fullerene, pass through a succession of carbon clusters which are characterised by ‘magic’ numbers related to high reactivity and maximisation of the number of dangling bonds per cluster. There is a critical high temperature nucleation leap into three dimensions at the corranulene kernel C,,,. This is determined by the appearance of a pentagon-based defect-the wedge disclination-which is then in turn responsible for the growth of C,,, multiple (or “hedgehog”) disclinations, higher order fullerenes, nested (and seeded) onion-like clusters and, ultimately, tiny crystalline stable polyhedra. Disclinations play a role in the development of three-dimensional aromatic molecules similar to that of screw dislocations in crystal growth. (Lewis T. Chadderton
and Eugene G. Gamaly)
epitaxiality (i.e. axis relations?) has not been The integrity of the carbon capsule established. produces remarkable resistance of the aerosol towards ambient oxidation of the metal, a surprising result given the extremely high surface-area-to-volume ratio of the population of tiny platelets and the susceptibility of most if not all of these metals to oxidation by air. Capsule integrity is also graphically illustrated by the resilience of a mercury fulleroid under the high vacuum Electron-beam heating while of a TEM column. imaging in the Hg case leads to some fascinating microstructures as the liquid metal separates from the carbon shell and agglomerates with nearby droplets. (T. J. Senden, K. H. Moock, J. D. FitzGerald, W. M. Burch, R. D. Browitt, C. D. Ling, and G. A. Heath) Faculty of Engineering
and Information
Technoloav
We have previously studied in detail the quantitative kinetics of the chemical cross-linking reactions in epoxy resins, and the phase separation in modified resins during the curing process. Presently we are extending these studies to include a third phase, namely highlyoriented pyrolitic graphite (HOPG). Preliminary results indicate that the curing of the resins in contact with the HOPG (0002) basal plane causes depletion of the segregated (particulate) phase in the region within 100 microns of the epoxy-HOPG interface. The next step is investigation of the effects that could arise when curing on interfaces that are oriented perpendicular to (0002) of HOPG. A study of the microstructure of the HOPG reveals plate-shaped domains of near perfect threedimensional graphite crystal stucture, extending approximately 100 mn perpendicular to the basal planes, but tens of microns or more in the graphite plane. All domains share a common (0002) orientation, but the crystal axes are misoriented at every domain boundary. Some of the domain boundaries appear to have parted slightly and now exist as microcracks. In bonding of epoxy onto a macroscopic HOPG face perpendicular to (0002), atomic configuration at the interface could therefore be changing on the 100 nm scale due to the presence of domains and domain boundaries. The group continues studies of the interlaminar strength between carbon fibres and polymer matrix, in particular in relation to marine environment. This year the first prepregging laboratory in Australia for advanced composite materials will be made operational with the installation of a WEB drum winder with high temperature capability, a twin screw extruder, and a high temperature/high pressure autoclave. (Zbigniew
Stachurski)
Research School of Chemistry Professor J. W. White and co-workers have completed a number of projects, mainly relating to superconductivity and fullerenes. Topics include the following:
Structures of ammoniated A$,, superconductors (R. J. N. Durand, W. K. Fullagar, G. A. Lindsell, P. A. Reynolds, J. W. White). Superconductivity measurement W. K. Fullagar, J. W. White).
- (R.
Bramley,
Low temperature gas intercalation in alkali graphite intercalates - (G. A. Lindsell, G. Lockhart, P. A. Reynolds, J. W. White). Inelastic neutron scattering and superconductivity of Rb,C,,(NH,)x - (C. J. Carlile, R. J. N. Durand, W. K. Fullagar, P. A. Reynolds, F. Trouw). Structures and vibrations of alkali metal fullerides (W. K. Fullagar, P. A. Reynolds, J. W. White).
-
Vibronically resolved absorption spectra in C,, anions - (W. K. Fullagar, J. W. White, G. Heath). Low temperature gas intercalation in alkali graphite intercalates - (G. A. Lindsell, P. A. Reynolds, J. W. White). Research School of Earth Sciences The main topic of research has been the interaction of mesophase with metal surfaces. For example, under particular conditions, mesophase readily wets and coats the surface of a copper plate, whereas an aluminium plate does not wet. The nature of the surface interactions is being investigated with emphasis on the true nature of the interface-whether there is an oxide or other film, for example. (A. Lee, G. H. Taylor) Research School of Phvsical Sciences and Engineering A new defect-based model for the growth of the fullerene molecule, C,,, assembling from a hot, homogeneous and dense ensemble of carbon atoms, or ‘primeval soup,’ has been presented in a paper entitled “Fullerene genesis by ion beams II: Disclinations and the corranulene road.” Routes, comprising swift open channels to fullerene, pass through a succession of carbon clusters which are characterised by ‘magic’ numbers related to high reactivity and maximisation of the number of dangling bonds per cluster. There is a critical high temperature nucleation leap into three dimensions at the corranulene kernel C,,,. This is determined by the appearance of a pentagon-based defect-the wedge disclination-which is then in turn responsible for the growth of C,,, multiple (or “hedgehog”) disclinations, higher order fullerenes, nested (and seeded) onion-like clusters and, ultimately, tiny crystalline stable polyhedra. Disclinations play a role in the development of three-dimensional aromatic molecules similar to that of screw dislocations in crystal growth. (Lewis T. Chadderton
and Eugene G. Gamaly)