Atomization of Viscous Fluids for Digital Scent Technology Using An Integrated Micro-droplet Generation Platform

Project: Research

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Our team will develop a novel wearable digital scent-generation device for applications in enhancing Virtually Reality user experience. Currently, no widely-accepted technology to reliably and accurately dispense smell on-demand exists, especially for wearable devices. We will usemicroelectromechanical systems(MEMS) technologies to fabricate arrays of microheaters and nozzle orifices to realize a wearableviscous fluid atomization platformfor digital scent generation. An important feature of this atomization platform is its ability to produce 10µm (or smaller diameter) fluid droplets as mist, because droplets larger than 10µm are less likely to be absorbed by the olfactory tissues. The device could also release multiple scents to enhance the users’ experience by activating their sense ofsmell. One of our ultimate goals for this device is to integrate it with ECG (electrocardiography), EEG (electroencephalogram), and skin conductance sensors to quantify emotional changes such as heart rate variation, relaxation, and stress when different scents are activated.Currently, the most prevalent portable atomizers are based on using lead-zirconium-titanate (PZT) as a high-frequency piezo-actuator to generate small fluidic droplets. A major drawback of this technology is that lead is a harmful material that can damage the nervous system and cause brain disorders, particularly in young children. The fine particles generated by PZT-based technology may be contaminated and are thus not suitable for daily life applications. Furthermore, common piezoelectric atomizers such as ultrasonic nebulizers are unable to aerosolizeviscousfluids, whereas jet atomizers are inefficient and inconvenient because they require compressed air. Our team has already demonstrated the feasibility of a lead-free atomizer to atomize fluids with viscosity about 200 times greater than water. Based on that platform, we will demonstrate a silicon-based viscous fluid atomizer for on-demand generation of droplets that can be efficiently absorbed by olfactory tissues in this project. There are several critical engineering challenges and scientific issues that will be addressed in this project in order to realize a small footprint and reliable viscous fluid atomizer: 1) enhancement of capillary flow rate in the atomizer’s chambers by controlling fluid viscosity via temperature; 2) determination of optimal ejection duty cycle to ensure long-term operability of the atomizer without significant reduction in droplet ejection time response; 3) optimal chamber geometric design to control the size of bubble nucleation in order to ensure stable mode of droplet ejection. Details of our methodologies to address these issues are discussed in the proposal.


Project number9042639
Grant typeGRF
Effective start/end date1/01/19 → …