An absorption complex or compound between boron nitride and chromyl chloride was discovered and studied in some detail. The method used to prepare the boron nitride had some effect on the composition of the complex but for a given sample of boron nitride the equilibrium composition for temperatures from 0°C to 160°C was constant. The kinetics of formation were studied at 24.1°C, 67.1°C, and 117.0°C. The reaction was interpreted as diffusion controlled with two diffusion coefficients--each for a certain concentration range. The corresponding two energies of activation were 5.0 and 6.1 kcal. These are of the same order of magnitude as for similar processes. X-ray studies of the complex showed a strong reflection line at the same place as for the main layer separation in boron nitride itself. There could have been a small amount of reflection due to a greater layer spacing, but it was not detected. Water hydrolyses the chromyl chloride in the complex, leaving the original boron nitride and a solution of dichromate and HCl. Carbon tetrachloride would not dissolve out the chromyl chloride from the complex. Similar complexes of chromyl chloride with disulfides of molybdenum, tungsten and uranium and of cupric and aluminum chlorides with boron nitride were discovered but the kinetics of their formation were not studied. The theory of formation of lamellar compounds is discussed. / Science, Faculty of / Chemistry, Department of / Graduate

Polyhedral boranes and carboranes have acquired their popularity for constructing meso and nano-size structures for an array of applications from pharmaceuticals to material science. These three-dimensional boranes range from 4 to 22 boron atom per molecules with delocalized bonding analogous to aromatic compounds. The unique vibrational spectroscopy of the BH function allows for possible application of these species to bioimaging. Silver nanoparticles functionalized with ortho-carboranes have been reported for bioimaging using Surface-enhanced Raman scattering (SERS). The silver nanoparticles were functionalized with antibodies specific to cancer cell receptors. Bonding thiol-substituted carboranes to these particles allowed for observation of enhanced Raman signals as the imaging mode. Here, attempts to synthesize second generation carborane molecules with additional Raman-active group such as nitrile were conducted. Hybrid diblock copolymers have the ability to self-assemble in different morphological patterns depending on the type and ratio of monomers and the compatibilities in various solvents. Linear hybrid diblock copolymers were synthesized by ring-opening metathesis polymerization (ROMP) reactions with norbornenyl-based decaborane and various amounts of norbornene and norbornenyl-ester derivative monomers. Their self-assembly behaviour in various solvents were characterized by NMR, TGA, DSC, and SEM. P(norbornene)60-b-p(norbornenyl-decaborane)40 polymers showed lamellar morphology patterns when slowly evaporated from chloroform. Based on results and the SEM images, a few of these diblock copolymers were used as ceramic precursors and pyrolyzed to elevated temperatures forming boron nitride and boron carbonitride nano-ordered ceramics

Polyhedral boranes and carboranes have acquired their popularity for constructing meso and nano-size structures for an array of applications from pharmaceuticals to material science. These three-dimensional boranes range from 4 to 22 boron atom per molecules with delocalized bonding analogous to aromatic compounds. The unique vibrational spectroscopy of the BH function allows for possible application of these species to bioimaging. Silver nanoparticles functionalized with ortho-carboranes have been reported for bioimaging using Surface-enhanced Raman scattering (SERS). The silver nanoparticles were functionalized with antibodies specific to cancer cell receptors. Bonding thiol-substituted carboranes to these particles allowed for observation of enhanced Raman signals as the imaging mode. Here, attempts to synthesize second generation carborane molecules with additional Raman-active group such as nitrile were conducted. Hybrid diblock copolymers have the ability to self-assemble in different morphological patterns depending on the type and ratio of monomers and the compatibilities in various solvents. Linear hybrid diblock copolymers were synthesized by ring-opening metathesis polymerization (ROMP) reactions with norbornenyl-based decaborane and various amounts of norbornene and norbornenyl-ester derivative monomers. Their self-assembly behaviour in various solvents were characterized by NMR, TGA, DSC, and SEM. P(norbornene)60-b-p(norbornenyl-decaborane)40 polymers showed lamellar morphology patterns when slowly evaporated from chloroform. Based on results and the SEM images, a few of these diblock copolymers were used as ceramic precursors and pyrolyzed to elevated temperatures forming boron nitride and boron carbonitride nano-ordered ceramics

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Thesis (M.S.)--University of North Texas, Aug., 2007. / Title from title page display. Includes bibliographical references.

Thesis (Ph.D.)--City University of Hong Kong, 2005. / "Submitted to Department of Physics and Materials Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy" Includes bibliographical references (leaves 147-154)

Thesis (M.Sc.)--City University of Hong Kong, 2005. / At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Aug. 31, 2006) Includes bibliographical references.

Thesis (M.Sc.)--City University of Hong Kong, 2005. / At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 1, 2006) Includes bibliographical references.

Graphene and monoatomic boron nitride as members of the new class of two dimensional materials are discussed in this thesis. Since the discovery of graphene in 2004, various aspects of this one atom thick material have been studied with previously unexpected results. Out of many outstanding amazing properties of graphene, its elastic properties are remarkable as graphene can bear strain up to 20% of its actual size without breaking. This is the record value amongst all known materials. In this work experiments were conducted to study the mechanical behaviour of graphene under compression and tension. For this purpose graphene monolayers were prepared on top of polymer (PMMA) substrates. They were then successfully subjected to uniaxial deformation (tension- compression) using a micromechanical technique known as cantilever beam analysis. The mechanical response of graphene was monitored by Raman spectroscopy. A nonlinear behaviour of the graphene G and 2D Raman bands was observed under uniaxial deformation of the graphene monolayers. Furthermore the buckling strength of graphene monolayers embedded in the Polymer was determined. The critical buckling strain as the moment of the final failure of the graphene was found to be dependent on the size and the geometry of the graphene monolayer flakes. Classical Euler analysis show that graphene monolayers embedded in the polymer provide higher values of the critical buckling strain as compared to the suspended graphene monolayers. From these studies we find that the lateral support provided by the polymer substrate enhances the buckling strain more than 6 orders of magnitude as compared to the suspended graphene. This property of bearing stress more than any other material can be utilized in different applications including graphene polymer nanocomposites and strain engineering on graphene based devices. The second part of the thesis focuses on a two dimensional insulator, single layer boron nitride. These novel two dimensional crystals have been successfully isolated and thoroughly characterized. Large area boron nitride layers were prepared by mechanical exfoliation from bulk boron nitride onto an oxidized silicon wafer. For their detection, it is described that how varying the thickness of SiO2 and using optical filters improves the low optical contrast of ultrathin boron nitride layers. Raman spectroscopy studies are presented showing how this technique allows to identify the number of boron nitride layers. The Raman frequency shift and intensity of the characteristic Raman peak of boron nitride layers of different thickness was analyzed for this purpose. Monolayer boron nitride shows an upward shift as compared to the other thicknesses up to bulk boron nitride. The Raman intensity decreases as the number of boron nitride layers decreases. Complementary studies have been carried out using atomic force microscopy. With the achieved results it is now possible to successfully employ ultrathin boron nitride crystals for precise fabrication of artificial heterostrutures such as graphene-boron nitride heterostrutures.