The research objective of this award is to investigate dynamically tunable nanostructured surfaces to manipulate multi-phase microfluidics for lab-on-a-chip, energy, and thermal management applications. The nanostructures will be fabricated in silicon with ferromagnetic tips, such that the inclination of the nanostructures will change upon the application of a magnetic field. Experimental investigations will be performed to understand how geometrically tunable nanostructures affect interfacial phenomena, apparent contact angles, and surface tension forces. Techniques used for these studies will include diffraction limited microscopy, scanning electron microscopy, and goniometry. The characterizations will be aimed to develop a correlation between nanostructure inclination angle and droplet/bubble contact angles. Experimental studies will subsequently be performed to examine the ability to modulate surface tension and to promote droplet/bubble departure in microchannels on demand.
The research will provide new methods to develop tunable nanostructures and fundamental understanding of the interactions of the liquid-air/vapor interface with these structures. Design guidelines for tunable nanostructured surfaces will be attained to achieve controlled droplet/bubble departure processes, which is one of the main challenges in many microfluidic systems. In addition, the results from these studies will provide the necessary framework, experimental techniques, and knowledge to allow investigations of related interfacial phenomena such as tunable surfaces for drag reduction, directional liquid spreading and draining, droplet manipulation, and liquid confinement.
