| Since the birth of nanomaterial in the last 90s, lots of attention has been paid to its nucleation, crystallization, oriented growth, stability, assembly and applied into a number of areas, such as physics, chemistry, materials and biomedical science. In various fields, compared with bulk materials, nanoscale and nanostructured materials with new structure and superior functional properties have demonstrated theri excellent performance, and have a vast market and prospects. Among them, much concern has been paied to the polymer induced inorganic nanoscale assembly and crystallization process. Nanomaterials with different structures and properties can be prepared when familiar with the design and assembly procedure. The nanoscale and nanostructured materials on the one hand retain the characteristics of their parent nanoparticles, such as large external surface, rich structural properties and active sites, and on the other hand, can solve control deficiency and bring convenient in the specific application field because of their large size and adjustable assembly process.However, there are still lots of gaps due to a range of issues, such as the inherent defects for various assembly methods, lack consideration for application, insufficient understanding to the synthesis process, and vague crystallization mechanism. Together with little know about how to fully embody the advantages, these problems have severely impeded the further development into related areas. Thus, it will be meaningful to deepen polymerization process and obtain the nanoscale assembly with a certain shape and structure of polymer. Due to aspiring significance, this will favor for the design and provide more choice of nanomaterials with outstanding specific features.This thesis is focus on "polymer induced nanoscale assembly, nanostructure transformation and crystallization". Based on this, three aspects have been put forward, i.e. "design and control of polymer structure and polymerization", "nanoscale assembly and its formation mechanism" and "functional inorganic nanomaterials". In detail, nanozeolite colloidal solution without any further purification and treatment has been used in the improved polymerization induced colloid aggregation (im-PICA). Through a full study of the reaction conditions and nanosurface properties, precise control and regulation have been paid into the urea-formaldehyde resin polymerization process. The morphology and composition of poducts were finely controlled through simply adjusting the acidity of the polymeric system. A polymerization-velocity-match (PVM) mechanism was proposed to explain the morphology variation of the samples under different polymerization conditions. Owing to their stacking secondary pores and large external surface inherited from nanozeolite, the as-prepared zeolite microspheres (ZMSs) displayed an improved catalytic performance to various catalysis reactions. Moreover, induced by polyaspartic acid with a changing charge density on its molecular structure, the assembly and crystallization process of calcium phosphate have been investigated in the solution. And combining with positive charged chitosan as matrix, further study has been paid to the interfacial deposition process. The above researches extend the synthesis methodology of nanoscale and nanostructured materials, and also enrich the existing theory and mechanism. All of these lighten the new structure materials with outstanding performance for catalytic and biological appication. The dissertation will be divided and discussed into seven chapters:Chapter III discussed the preparation of P-ZMS using im-PICA. It is the first time that using nanozeolite colloid solution just after hydrothermal process without any treatment in PICA method,?-60 was taken as the typical nano-unit in the one-step assembly and synthesis procedure. The method is a simple and convenient to attain ZMSs with a prospect of low cost and large scale. By the variation of components, ZMS with different morphologies and structures can be assemblied, and acidity in this synthetic system is viewed as a crucial control element. Through the probe to the changes of zeta potential, it may indicate how/what will take place in polymerrization process. And PVM mechanism can explain the assembly process and structure transformation. Retained with properties of nanozeolites and inherited mesopores after removing UF polymer, ZMS may show broad prospects in catalysis particularly in the reaction controlled by diffusion, interfered largely by side-reactions, and taken at low temperature.Chapter IV investigated the im-PICA assembly process further using nanozeolite with different Si/Al2 ratios and structures. Inspite of changes of the synthetic condition and nanosurface properties, the morphologies and structures evolution confirmed the correctness of PVM mechanism. Also, through the control of polymerization process, urea formaldehyde resin protecting (UFP) method can be used to synthesis template-free mono-dispersed nanozeolite with different sizes and structures. Using urea formaldehyde resin moulding (UFM) method can acquire zeolite monolith with macropores and micropores. Furthermore, combined with metal salts in the synthetic system, metal@ZMS can be prepared simply.Chapter?studied four useful reactions catalyzed by ZMS. The two of them are liquid phase reactions under low-temperature, i.e. dynamic kinetic resolution and fructose dehydration into 5-hydroxymethyl furfural. The other two are gas phase reactions, i.e. C4-olefin cracking at high temperature and alkylation at low temperature. Compared to commercial zeolite, ZMS maintains unique advantages such as the retained larger external surface, short channel, accessible active sites, and characteristic mesopores. So, reactants and products have little diffusion limit, quick access and escape from the active sites. Thereby, due to slow carbon deposition and larger carbon capacity, catalyst life will increase. And based on the probe to the four different reactions at various conditions, ZMS catalyst showed a better catalytic effect than commercial zeolite.Chapter?described polymer induced mesoscale assembly and transformation process for calcium phosphate crystallization. Firstly, polyaspartic acid with different charged density was used to study the assembly process in solution. The system with different conditions was applied to investigate the morphology and structure evolution, such as concentration, temperature, induction time, and organic compound content. Also, the successful capture and observation of the detailed process elucidated two competing reactions existing in the crystallization and further verified the classic "polymer induced mesoscale transformation". Moreover, through positive charged polymer matrix-chitosan, the crystallization process was introduced to interface. Induced by the two kinds of polymers, morphology and structure changes were investigated, and the competitive crystallization between solution and interface was put forward. The as-synthesized calcium phosphate membranes with different structures showed different response in the cell adhesion and proliferation in biocompatibility test.In summary, polymer induced nanoscale assembly and nanostructured crystallization were studied through the regulation of the charge density of polymer and polymerization process. Various inorganic materials with different nanoscales and nanostructures were attained and their polymer induced assembly crystallization was dicussed in elaboration. Through the proposed "polymerization-velocity-match" mechanism can explain the whole assembly procedure and structure variation. The two competing reactions and crystallization between solution and interface reaction further illustrated the mesoscale transformation. Besides the novel nanostructures with functional properties, several mechanism and synthetic strategies have been proposed in this work, which will open up opportunities for the synthesis and design of new nanomaterials and provide a reference and instructive sight for catalytic reactions. |
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