The research objective of this project is to investigate new methods to direct colloidal assembly for robust, controllable and scalable manufacturing of various structured functional nanomaterials. Specifically, dielectrophoresis (DEP)-directed assembly of nanocolloidal building blocks under ac-electric fields of varied frequency and voltage will be explored to produce hierarchical nanostructured materials and devices, aiming to a development of prototypical nanoscale manufacturing schemes. Owing to the currently inadequate understanding of nanocolloidal DEP behaviors, the fundamental of nanoscale ac-polarization and DEP-induced dynamics will be examined and understood with latex nanoparticles of varied size from 10-100 nm in aqueous media as a model system. To enable in-situ and sensitive experimental characterization, ultrafast singe-particle fluorescence spectroscopy technique integrated with microfluidic devices will be employed to examine the scaling of nanocolloidal DEP characteristics with colloidal size and conductance and medium conductivity, which can be used to effectively scale the nanomanufacturing of hierarchical nanocolloidal assembly with varied colloidal dimension and suspension condition.
If successful, directed assembly of various nanocolloidal building blocks under ac-electric fields can be developed as a practical and versatile method to achieve robust, controllable and scalable nanofabrication and nanomanufacturing of structured functional nanomaterials, composites and coatings. When combined with current microfluidics technology, the DEP-based approach for nanocolloidal manipulation and assembly can be transformative and broadly applied to emerging bio/nanotechnology, such as the synthesis of novel photonic materials and porous separation membranes, rapid fabrication of biosensors and protein crystal arrays. Graduate and undergraduate student participants, as well as underrepresented minorities including female students in engineering majors, will be trained with new and advanced nanomaterials synthesis and characterization techniques through classroom instruction and laboratory research. This project also seeks to establish a strong coalition with relevant industrial corporations to help students, scientists and engineers work well together.