Liquid-phase Synthesis, Characterizations, And Properties Investigation Of Hydroxyapatite, Silica And Their Hybrid Structural Material

Inorganic biomaterial (e.g., calcium carbonate, hydroxyapatite and silica) has attracted considerable attention due to its excellent biocompatibility. The synthesis of nano-inorganic biomaterial with uniform structure and novel morphology has essential significance and is still a challenge to date. The content of this thesis is synthesis of novel hierarchically porous silica superstructures. On the basis of mesoporous silica, functional silica based composites can be successfully synthesized via a layer-by-layer method. The catalytic performance of silica/CuO composites has been investigated. In addition, hydroxyapatite mesocrystals can be obtained via the induction of thermal effect. The detailed contents are as following:1. A novel kind of hierarchically porous silica superstructures was prepared using micelle-directed nucleation approach under mild conditions. Herein, magnetic colloid particles can act as heterogeneous-nucleation initiating centre, Poly (acrylic acid)(PAA) and Hexadecyl trimethyl ammonium bromide (CTAB) as dual-templates to precisely modulate the morphologies and surface textures of the prepared silica. Results demonstrated that the prepared porous silica displays three-branches-, calabash-, capsule-, and hollow sphere-like morphologies via simply changing mass ratios of PAA/CTAB. As a result, a plausible formation mechanism for the obtained hierarchical silica structures was proposed. Generally, it was considered that the synergetic assembly effects from among magnetic particles, PAA, CTAB, and silica precursors can significantly modulate early preferable nucleation modes and particle growth, and therefore causing the formation of novel hierarchically silica structures.2. A facile layer-by-layer assembly process to grow HKUST-1MOF on mesoporous SiO2substrate and the subsequent synthesis of porous SiO2/CuO composite and octahedron CuO by thermal-decomposition of HKUST-1@Meso-SiO2and HKUST-1, respectively. CuO nanoparticles in porous SiO2/CuO composite are well-crystallized and uniform dispersed with a narrow size distribution. In addition, the porous CuO-based samples serve as catalysts in CO oxidation; results demonstrated that both porous SiO2/CuO composite and octahedron CuO are active in catalyzing CO oxidation. However the presence of SiO2core alters the decomposition behavior of the HKUST-1shell and thus the microstructure of the resulting SiO2-supported CuO particles, and the intrinsic catalytic activity of octahedron CuO is higher than that of porous SiO2/CuO composite.3. Hydroxyapatite mesocrystals with diverse hierarchically surface textures have been successfully synthesized in the presence of non-ionic surfactant (Brij56) and urea at mild conditions. HAP samples with various surface morphologies, including, slices with smooth surface and novel nervation pattern, rectangular blocks with diverse aspect ratio, rectangular blocks with two symmetrically etched sides, three dimensional (3D) porous architectures, macroporous mesostructures and nanobelts, can be obtained by simply altering the reaction temperature that ranged from50to130℃. Moreover, the as-obtained HAP products can also display better crystalline feature and morphology evolution regulation with the reaction time prolonged. Specially, the thermal effect can effectively modulate the nucleation and crystal growth rate at present reaction systems. With reaction temperature increasing, the formed HAP samples can undergo crystallization-dissolution-recrystallization process, and finally lead to the formation of the HAP samples with distinct surface textures.