NER: Manipulation and 3D Organization of Nanoparticles Using Dielectrophoresis

This project was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NER, and it addresses the manipulation and organization of nanoparticles. The organization of colloidal particles into one-, two- and three-dimensional ordered structures represents the first step towards the fabrication of a large number of miniaturized products of great technological importance. Structural attributes such as long-range order, high packing density, high surface-to-volume ratio, and reproducible shape and dimensions are highly desirable. Force microscopy and optical tweezers have been used for the manipulation of a small number of individual particles, while colloidal crystallization and templating have been used for particle organization; however, big challenges remain. Our goal is to develop a methodology that utilizes nonuniform electric fields (dielectrophoresis, DEP) to direct the organization of nanoparticles into well-defined two- and three-dimensional ordered structures (e.g., pyramids, parallelepipeds) with prescribed length scales and composition. Such methodology is scalable and readily automated, and would allow the manufacturing of functional materials with nanometer-scale order that can be used for their structural properties, e.g., photonic materials or high density data recording devices, and/or their structure, e.g., prefabricated blocks towards more complicated devices ("bottom up" strategy). We will follow a systematic approach, from 2D to 3D order and from microparticles to nanoparticles. This research is exploratory and high risk since forces developed during the organization process may nullify the DEP effect, and the dimensions of the electrodes required for the efficient organization of nanoparticles may be challenging to fabricate. This research should lead to significant advancements in the field of nanotechnology by the (a) fabrication of nanostructures having hierarchical-order using DEP, and (b) development of process design tools for efficient implementation of DEP in large-scale manufacturing. The graduate and undergraduate students who will be involved in the project will gain valuable experience, while industry (and the community) will benefit from the expertise on nanostructures and nanomanufacturing developed at the university through this research.