This Award was received in response to Nanoscale Science and Engineering Initiative, NSF04-043, Category NER. The objective of this research is to explore a novel approach to control the distribution of droplet sizes produced in an electrospray. The approach is to use a controlled dose of electrons to charge the droplets to a point where electrostatic repulsive forces, which tend to break up the droplet, overcome surface tension forces holding the droplet together. By controlling how the droplets are broken up into smaller droplets, one can precisely control the amount of material delivered by the droplet to a surface. Numerical simulations will be used in conjunction with the experiments as a proof-of-concept and will help guide identification of the optimal electron characteristics (current density and energy) for a given initial droplet population to produce the desired change in the size distribution. An electrospray provides a means of delivering droplets containing precursor materials for subsequent incorporation into an assembled nanostructure. Controlling the composition of nanostructures is one way to tailor their properties to meet the needs of emerging applications in a wide variety of industries. This approach, if successful, will allow the delivery of smaller sized droplets than is possible using the electrospray process alone. The work in this one year exploratory effort will address the feasibility of the concept as well as lay the groundwork for further development of the technique for nanofabrication. The experimental and computational investigations will involve both graduate and undergraduate students as active participants in the development of diagnostics and computational tools. Development of these tools will promote learning through WPI's project-based educational system that requires each undergraduate conduct a technical team-project.
