Preparation Of Zinc Oxide Using Polyamidoamine Dendrimer As Template

Zinc oxide is a functional inorganic material with an extensive foreground, it plays an important role in daily chemical industry and national defense industry. It also a new generation II-VI compound semiconductor with direct wide-band gap and a hexagonal wurtzite structure. With the high technology fast development and the demand for new compound material, more attention is paid to the development and application of high quality zinc oxide.The polyamidoamine(PAMAM) dendrimer is a kind of branch structure polymer with a special surface configuration and organic functional groups. The structure of polymer is very tidy and fine, the surface has abundant -NH2 or CH2CH2COOCH3 and the inner is cavity.In the thesis, PAMAM dendrimers from 0.5 generation to 4.0 generation were synthesized via the divergent method. Using dendrimer special space and surface structure as template, different sizes ZnO had been prepared. The results were characterized by FT-IR, XRD and SEM. The influential parameters such as dendrimer template, solvent and other condition were studied in detail.The results show that PAMAM dendrimer has been synthesized in methanol solvent by divergent synthesis using ethylenediamine and methyl acrylate as raw materials. Strictly controlling of reaction condition, the yield was high to 97% under 30℃reaction for 24 hours. Using different generation PAMAM dendrimer as template, the hexagonal wurtzite structure ZnO had been prepared after calcinated at 300℃. Different generation PAMAM dendrimer have great influence on ZnO. Under the same condition, using 2.0G PAMAM as template, the average size of crystal cluster ZnO particle was 1μm long with diameter 150nm; using 3.0G PAMAM as template, the average size of hexagon flake ZnO particle was about 400nm and the average thickness about 20nm. Solvent also has influence on the structure of ZnO. In ethanol solution, using LOG and 4.0G PAMAM dendrimer as template, the spherical zinc oxide with diameter less than 100nm and the shape of hexagonal prism with a diameter 400nm were prepared respectively; in water solution, irregular shaped zinc oxide with diameter between 50nm and 200nm and block zinc oxide with diameter about 400nm had been synthesized.