Calcium Carbonate Biomimetic Materials And Reversible Heat Caused By The Preparation Of Photochromic Materials

Calcium carbonate is the most widely used biomineral in the world. There are three distinct crystalline phases, which have their respective morphologies: calcite (rhombohedra), aragonite (needle) and vaterite (polymorph sphere).In the dissertation, soft-templates were used to regulate and control the growth progress of calcium carbonate. Versatile morphologies and different polymorph of calcium carbonate were produced in the experiences, and the mechanisms of these results were investigated. The main information is as follows:1 The crystallization of calcium carbonate in the presence of mixed ethonal-water solvents and the effect of stirring time on the morphologies have been investigated.2 The aqueous solution of anionic surfactant DDS was used as an effective soft-template to regulate and control the crystallization of CaCO₃. The important parameters, such as the concentrations of reactant and DDS were systematically studied. The results indicate that DDS has effect on the morphology and size of CaCO3 crystal.3 The aqueous solution of sucrose was used as an effective soft-template to regulate and control the crystallization of CaCO₃. The results indicate that the sucrose has effect not only on the polymorph but also on their morphology and size of CaCO₃ crystal.4 The effects of magnesium ions on the growth of calcium carbonate were investigated under different molar ratio of magnesium ions to calcium ions, and the mechanism of effect was also discussed.Thermochromic material is a special functional material, which is made from chromic substance and other accessorial components. It has the characteristics that the color changes with temperature.In the dissertation, a series of reversible thermochromic materials were prepared with different pH value and proportioning, cresol red as chromophoricreagent, boric acid as delomorphic reagent and AI2O3 as filler. The results indicate that with the increasing of pH value, the temperature of color changing gradually grows. Based on the IR spectra, it is presumed that the thermochromic mechanism of the material is that cresol red is lactone form at low temperature and in quinoid form at high temperature. The main innovative point:In the presence of soft-template, we obtained pure CaCCh particles without additive.