| Materials in confined geometries show remarkable difference in static and dynamic properties from the correspondent bulk, because of the introduction of finite size effect, the restriction in the dimensionality, and the competition between the molecule-wall and molecule-molecule interaction forces. Understanding the molecular origin of confinement-induced changes is of fundamental interest to many processes, such as lubrication, adhesion, coating, chromatography, and membrane separation. In this dissertation, the one-dimensional confined silicate galleries are used as the template. The confinement effect on the behaviors of hexadecylamine and polystyrene molecules are studied by the combination of differential scanning calorimetry (DSC), X-ray diffraction, and Fourier transform Infrared spectroscopy (FTIR).; Contrary to the assumption that has been followed for tens of years where amine molecules are considered to form completely ordered structure within the silicate galleries, the crystallinity of confined hexadecylamine is only up to 35%. The confined amine shows multiple melting transitions at temperatures much higher than the melting temperature of pure amine. Temperature-dependent FTIR confirmed that the melting of confined amine is not related to the melting of the three-dimensional crystal structure. Instead, it is related to the chain melting process: order to disorder or disorder to more disordered chain conformational transition. The ordering of the amine chain within the silicate galleries strongly depends on the amine concentration, the orientation of the amine, and the type of headgroup.; The behavior of polystyrene chains within the silicate layers is studied with and without the presence of solvent molecules. d-Spacing of the polystyrene nanocomposites has a minimum value when the residual solvent concentration is between 2–4 wt%. Different interaction level between the solvent molecules and polymer chains is considered to be the reason for this special d-pacing change behavior. By analyzing the ΔCp as a function of polystyrene concentration for the polystyrene nanocomposites, it is confirmed that the polystyrene chains confined within the silicate layers does not contribute to the ΔCp. The total amount of intercalated polystyrene is about 40 wt% of the clay amount and this amount would not change as polystyrene concentration changes. |
