A nanometer (nm) is one billionth (10-9) of a meter. When the dimension of a material drops within this nm length scale, the nature of the interactions between molecules and atoms within this material becomes different from that of the bulk. Such materials are not only fundamentally unique but also useful as “nano-scaled building-blocks” for a variety of applications.

     The dispersion of nanomaterials is crucial for understanding the fundamentals because aggregation significantly suppresses their superior properties. Also, dispersed nanomaterials have enormous surface and interfacial areas, which are essential for their intended applications, such as gas storage, energy conversion efficiency, transportation property, thermal stability, mechanical and optical properties. In our group, we study three classes of nanomaterials: 0-dimensional ZnO quantum dots, 1-dimensional carbon nanotubes, and 2-dimensional a-zirconium phosphate nanoplatelets.

ZnO quantum dots (QDs): ZnO is an important and attractive material. Its large bandgap of 3.3 eV and high exciton binding energy of 60 meV at room temperature are ideal for short-wavelength optoelectronic applications. We have developed a simple colloidal method to prepare monodisperse ZnO QDs with high purity. Recently, we have accomplished individually dispersed ZnO QDs in various polymer matrices without using organic surfactants. More recently, we successfully achieved the self-assembly of ZnO QDs into crystalline solids. Significant efforts have also been made on understanding the antimicrobial and cytotoxicity of ZnO QDs.

Carbon nanotubes (CNTs): De-bundling of CNTs into individual tubes is of tremendous importance. Recently, our group has developed a simple colloidal method to achieve individually dispersed CNTs in various solvents and polymers in large quantities. Exfoliated CNT network has been built. Significant effort is now underway to take the best advantage of exfoliated CNTs for various applications including mechanical reinforcement, electrical conductivity, nano- and micro- electronics and devices, and aerospace applications.

a-zirconium phosphate nanoplatelets (ZrP): Polymer nanocomposites containing exfoliated layered structure materials exhibit greatly improved mechanical, thermal, and barrier properties. Our group prepares synthetic layered compound based on ZrP with controlled aspect ratios. Fully exfoliated ZrP nanoplatelets have been achieved in polymer matrices. Future work will focus on fundamental understanding of the physical and mechanical behavior of nanoplatelets based polymer nanocomposites.