Biomimetic Synthesis Of Novel Carbonate Nanofibers And Their Patterning Arrays

In this dissertation, we have enriched and further developed the biomimetic approach to synthesize inorganic biomaterials. Some new synthesis strategies have been proposed to fabricate novel mineral materials as those in nature. Especially, the combination of a functional polymer with a patterned substrate allows it possible to grow micropatterned nanofibers under mild condition. The main results can be summarized as follows:1. Micropatterned calcite fibers have been fabricated by the combination of microcontact printing, the so-called polymer-induced liquid-precursor (PILP) and solution-precursor-solid (SPS) growth process. Organic frameworks on the substrate enable the mineral precursor deposit on the substrate selectively. Upon subsequent solidification and crystallization, the mineral precursor retains their morphologies and arrays on the substrate, providing a secondary template for patterning the location and morphology of two-dimensional calcite fibers. The detailed structures of novel fibers indicate they are in fact "mesocrystals". This biomimetic approach is expected for patterning growth of other functional inorganic materials in future.2. High aspect ratio, luminescent BaCO₃ nanowires and their micropatterned arrays have been synthesized in the presence of mixed additives of the copolymer and organic dye. The hybrid nanofibers show a time-dependent tendency of self-assembly into ordered structures. Combining with the copolymer, most dye molecules are kept in the nano-space between the nanofibers in a form of J-aggregate. The patterned nanowires display microregions-enhanced photoluminescent property under ultraviolet illumination.3. Double-stranded and cylindrical helical BaCO₃ nanofibers have been synthesized by using a phosphonated block copolymer as additive. The suitable growth conditions for the helical nanofibers have been studied. Most helical nanofibers are favorable to grow from the mineral films on the OTS-coated substrate in the solution with starting pH values from 3.5 to 4.5. A mechanism involving polymer-induced liquid precursors (PILP) and self-assembly process of nanoparticles for the formation of helical BaCO₃ fibers is proposed. These fascinating curved, spiral biomimetic superstructures have same morphologies as biogenic materials in nature. These results provide new insights into understanding of complex biomineralization processes in nature. This synthesis method could be extended to synthesize other inorganic materials with fascinating morphologies and structures.