Self-Assembly of Nanoparticles Functionalized with Mesogens

Assembly on metallic nanoparticles has attracted great interest due to their wide potential applications in semiconductors and nanocatalysis. Recent theories also suggest that they have the promises in providing materials base for metamaterials with interesting optical properties such as negative refractive index. While most previous attempts to design metamaterials rely on top-down techniques, in contrast, the bottom-up approaches based on the self-assembly of nanoparticles provide feasible and promising alternatives. Due to the combination of order and mobility at the molecular level, liquid crystalline molecules are perfect candidates for the synthesis and self-assembly of nanomaterials. It has been demonstrated that by covering nanoparticles with liquid crystalline molecules, strong anisotropy could be induced to affect the packing geometry of spherical nanoparticles, and long-range order could be achieved. These successful attempts include covering nanoparticles with rod-like mesogens, discotic mesogens and bent-core mesogens. In this thesis, nanoparticles covered with hemi-phasmids as well as dendrimeric liquid crystal forming molecules, and some relevant liquid crystal compounds have been comprehensively investigated by Small-angle X-ray Scattering (SAXS), Grazing Incidence Small-angle X-ray Scattering (GISAXS) and Polarized Optical Microscopy (POM). A number of 1-D lamellar, 2-D hexagonal columnar, and 3-D cubic nanostructures have been successfully achieved. The electron density maps for those liquid crystalline phases are reconstructed based on the integrated diffraction intensities. The corresponding models of self-assembled nanostructures are proposed depending on the electron density maps and molecular structures. Molecular modelling and molecular dynamics simulation have been carried out to verify the credibility of proposed models.