Dry Powder Dispersion; It’s Only Up From Here
Research team led by associate professor in mechanical engineering discovers dry powder dispersion method—leads to new patent and endless real-world applications
“Imagine it’s like driving down a dusty road. Your car tires are breaking up the dust, with plumes of it going up into the air. Now, how do we make that type of action sustainable and steady for dry powders?”
Within seconds, Dr. Ranganathan Gopalakrishnan describes his multiyear study of aerosol generation and powder dispersion in a visually striking way. It’s taken years, however, of dedicated, disciplined research for him and his team to study and replicate continuous, scalable generation of aerosol from commercial powders using ultrasonic dispersion. (Think of those tires spreading the steady plume of dust.)
Gopalakrishnan is the R. Eugene Smith Associate Professor and Graduate Program Coordinator in the Department of Mechanical Engineering. He received his Ph.D. in mechanical engineering from the University of Minnesota in 2013 and Bachelor of Technology degree in mechanical engineering from the National Institute of Technology in Tiruchirappalli, India.
Since 2017, Gopalakrishnan and his team at the University of Memphis have been studying a powder dispersion method that uses ultrasonic waves to disperse dry powders as aerosols. “What we were trying to do then and now is use ultrasonic waves and lift up dry powder particles without touching them,” Gopalakrishnan says.
The key is not having to touch them. That’s why dry powder dispersion is often favored over wet dispersion or other conversion methods. If offers a better ability to preserve chemical purity and crystalline structure from the powder to aerosol phase and to work “cleaner” in a solvent-free and room-temperature operation.
“Powders that are used industrially are often sticky during handling. To better maintain purity and sterility, powders should be handled with minimum or no contact with surfaces,” Gopalakrishnan says.
The Herff College of Engineering at the University of Memphis initially funded Gopalakrishnan’s aerosol generation and powder dispersion study. In 2018, the FedEx Institute of Technology stepped in as well and helped fund continuation of the study.
Making Headway
To date, Gopalakrishnan and his team have been able to demonstrate tunable high concentrations of microparticles that were steady for periods beyond one hour. Their studies and resulting findings have garnered publication in two academic journals, Aerosol Science and Technology and Powder Technology.
More notably, in June 2022, Gopalakrishnan and his team were granted a patent for a powder dispersion device from the U.S. Patent and Trademark Office—a patent that enables future commercialization of this powder-diversion device.
“The Office of Technology Transfer at FedEx has been supportive in this area as well, leading the patent-application process. It’s been immensely helpful,” Gopalakrishnan says.
The Impact
While initial talk of microparticles, dispersion and devices may produce a head scratch or two, the impact of Gopalakrishnan’s research on our daily lives is real—and fascinating. “Aerosols play a role in everyone’s lives,” he says.
Consider that we use many products, almost every day, that could be affected in terms of cost, quality and availability as a result of this study and Gopalakrishnan’s dedicated team. That turns the dial toward a real-world application.
“Powders are the basic blocks from which many consumer products are made. Many pharmaceuticals, food and agricultural products start as powders. Think, for example, of medication, like nebulizers and pills, or food for newborns and infants, like baby formula—even ag products, like fertilizer and feed stock. They all started out as a dry powder,” Gopalakrishnan says.
Powders that are highly cohesive, or “wet,” are “stickier” and difficult to detach from the walls of process equipment or while dispersing with moving parts, like blades, mixers or fans. Simply put, they can clog up the process, like a slow-moving drain. This, in turn, can result in an increase in handling and clean-up costs, and how much energy is used to produce the end product.
Dry powders, however, are easier to source, store and handle. As a result, they offer wider and more cost-effective applications ranging from medical and environmental science to manufacturing technology.
Where This Could Lead
On the application side, Gopalakrishnan says, the newly patented device opens doors to new manufacturing conversations. One example of a possibility? Talking to manufacturers that use powders for feed stock. Their manufacturing costs ultimately could be reduced by using this new device, but that’s down the road, he cautions, as trials still need to be completed.
Additionally, securing the patent means protection to talk more publicly about this project and device, including in scientific journals and conferences. Or even starting a company or license it to other companies and groups that see the device’s potential.
From a scientific standpoint, Gopalakrishnan and his team already see research extending into learning more about why and how the particles lift up—what’s going on at the fundamental level to perhaps spur new discoveries.