The interwall spacing of multi-walled carbon nanotubes has an effect on their physical and chemical properties. Tubes with larger interwall spacing - compared to the spacing where the carbon atoms are in their natural distance to each other - are for instance expected to be mechanically less stable. Considering the MWCNT interwall spacing’s dependence on the tube size, three interesting previous studies with slightly different conclusions can be found. All of them conclude an increase of the interwall spacing with a decreasing tube size. We describe their analysis procedure, compare them to each other and to our own measured data. In the beginning of our analyses, we determine the expected inaccuracy for measured distances out of TEM images being up to 10 % and we show the impacts of the TEM’s defocus, a powerful setting in TEM imaging. Finally, we suppose that the interwall spacings are not as strongly varying as one previous study concludes, but our analyses are relatively in harmony with the two other studies. The interwall spacings from tubes with an inner diameter larger than 5 nm are relatively constant within the whole tube. Furthermore, it appears that the middle spacings (excluding the outer- and innermost ones) show values that are most consistent with the interlayer spacings of turbostratic graphite. In underfocused images, the outer- and innermost spacings tend to have values being slightly smaller than the middle ones from the same tube.

During recent decades metallic nanoparticles have been found very interesting due to their unique characteristics which make them suitable for different applications. In this research, for the very first time, we tried to perform selective surface photo activation chemistry on the targeted facets of nanoparticles while they are in suspension. This technique enabled us to form desired assemblies of nanoparticles. We focused on elongated shaped gold nanorod due to its unique surface plasmon resonance and probable biomedical applications. In this research we formed a dumbbell shape assembly of nanoparticles in suspension. A probable application for these assemblies can be in vivo imaging. Initially, we reproduced gold nanorods using existing techniques in prior papers and optimized them according to our research needs. A low rpm centrifugal separation technique was developed to efficiently separate synthesized gold nanorods from other shapes. Several characterization techniques were utilized to characterize nanoparticles at each step including UV-absorbance, zeta potential, and dynamic light scattering. Different generations of oligomers were synthesized to be used as gold nanorods coating, and each coating was tested and characterized using appropriate techniques. Our two-step coating replacement method using one of these photocleavable oligomers enabled us to achieve, for the very first time, selective UV photo activation of gold nanorod tips. The photo activated tips were then exposed to oppositely charged gold nanospheres to form dumbbell shape assemblies of gold nanorods and nanospheres. Furthermore, dumbbell shape assembly of nanoparticles was investigated and characterized. / Master of Science