This dissertation work addresses two important aspects of nanotechnology -
stable dispersion and self-assembly of colloidal nanostructures. Three distinctly
different types of nano-scaled materials have been studied: 0-dimensional ZnO quantum
dots (QDs), 1-dimensional carbon nanotubes (CNTs), and 2-dimensional alpha-zirconium
phosphate (ZrP) nanoplatelets. Specifically, highly crystalline ZrP layered compounds
with differences in diameters have been synthesized and fully exfoliated into monolayer
platelets with uniform thickness, followed by their self-assembly into liquid crystalline
structures, i.e., nematic and smectic. A novel colloidal approach to debundle and
disperse CNTs has been developed by utilizing nanoplatelets to gather and concentrate
sonication energy onto nanotube bundles. In such a fashion, CNTs are fully exfoliated
into individual tubes through physical means to preserve their exceptional physical
properties. Moreover, monodisperse ZnO QDs with high purity have been synthesized
through a simple colloidal approach. Exfoliated ZrP nanoplatelets are used to tune the
dispersion of ligand-free ZnO QDs from micron-sized aggregates to an individual QD level depending on the ratio between nanoplatelets and QDs. Dynamic analysis suggests
that the dispersion mechanism mainly involves the change of QD dispersion free energy
due to the presence of nanoplatelets, so that QDs can interact favorably with the
surrounding media. In addition, the nanoplatelet-assisted dispersion approach has been
utilized to disperse QDs and CNTs into polymeric matrices. Dispersion - property
relationship in polymer nanocomposites has been systematically investigated with
emphasis on optical properties for QDs and mechanical properties for CNTs.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/150919 |
| Date | 16 December 2013 |
| Creators | Sun, Dazhi |
| Contributors | Su, Hung-Jue, Cheng, Xing, Cheng, Zhengdong, Teizer, Winfried |
| Source Sets | Texas A and M University |
| Language | English |
| Detected Language | English |
| Type | Thesis, text |
| Format | application/pdf |
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