Mechanism And Experiment On The Crystal Growth Controlled By The Biomineralizational Template Method

Biological mineral is the step which minerals are becoming in organism, infact, they are very important components of organism and high-performancecomposite materials. The most immediately striking aspect of biomaterials is therange of exquisite and unique morphologies, which are frequently disparate fromtheir synthetic counterpart. Typical products of biomineralization are bones, teeth,shells, pearls, and so on. The general principles of biomineralization are introducedinto the synthesis process of inorganic materials. Simulating the biomineralizationprocess of the nucleation and growth of inorganic materials mediated by organicmatrixes and biomimetic synthesis of inorganic materials with higher performanceand more exquisite morphologies have become the focus of material science.Biomineralization is mother natures approach to advanced materials synthesis,and it attempts to chemically control the growth of inorganic crystals in theorganicsubstrate by adapting or imitating biological mineralization strategies. Thekey to the successful synthesis of an inorganic-organic composite is an understandingof the parameters that control the nucleation and growth of inorganic crystals underthe substrate in aqueous solution. In this thesis, we try some new substrates to controlthe polymorphism and morphology of crystal.1. We study the behavior of the CuSO4·5H2Ocrystals grown on the different state film. Theexperimental results demonstrated that the LB film in the liquid state has the ability of directingthe nucleation and grow of crystals. Moreover, the CuSO4·5H2O crystals grown on the liquid filmhave quite different orientation and morphology from those grown on the solid film.2. Control of crystal polymorph and size is very important in many applicationfields. In the present study, Au and Si substrates were used as solid templates tocontrol the growth of calcium carbonate (CaCO3) crystals have been described. The obtained composite CaCO3were characterized by using X-ray powder diffraction(XRD) analysis, Scanning electron microscopy (SEM) and Fourier transforminfrared spectroscopy (FTIR) measurement.3. The MPTS SAMS films is used as template to induce the nucleation andgrowth of KCl crystals. X-ray diffraction (XRD) patterns and optical microscopyimages show that the orientation and morphology of the crystals have successfullybeen controlled by changing the orientation and position of the self-assembly films inthe solutions.4. In the present study, uniform and rather flat melanin films with the dendritesstructure obtained using self-assembly technique on Si substrate. The structure offilm was confirmed by Fourier-transformed infrared spectrometry (FTIR), X-raydiffraction (XRD) and Scanning Electron Microscopy (SEM). Experimental resultsshowed that the grown on the Si substrate, self-assembly film had oriented quality.Furthermore, according to the results，a model of the secondary structure in themelanin films was suggested. Then the SAMS films are used to serve as templates toinduce glycine crystal growth. The results of experiment proved that it is not onlythat morphology and orientation of crystal can be controlled by the optimization ofthe structure and chemistry of the SAMS film.5.The control of crystal polymorphism of the trimorphic crystals of glutamicacid (Glu) grown in solutionsin the presence of formic acid、acetic acid，propionicacid，methanol，ethanol，propanol，butanol，acetone. The presence of acids insolutions induces-polymorphs of glutamic acid when the temperature of solutionsranges from70°C to0°C. At the same experiment conditions, the other additivesinduce α-polymorphs of glutamic acid.6. We demonstrate that silver colloid can serve as additive and induced theγ-form polymorph of glycine crystals in the netural solution. The silver colloid couldquickly affect the packing arrangements of glycine molecules in aqueous solutionleading to the competitive nucleation of the two polymorphs.