The nanometer-sized particles that are part of aerosol sprays and gases can be difficult to see and study. But by developing a new way to create aerosol gases with particles that are smaller than a wavelength of light but still optically visible, researchers at the Air Force Research Laboratory have found the means to study the behaviors of such aerosol gases and their nanometer-dimensioned particles and how they might be best applied in different applications.
Jake Fontana, the principal investigator for the patent-pending technique, notes that it brings the study of such aerosol gases to the benchtop: “We made an instrument which efficiently creates aerosols with nanometer-size particles. Because the particles are plasmonic, we can see them in real time,” he said. “This opens up a new world in being able to study nanoparticle gases at the benchtop.”
Plasmonic materials, such as gold, silver, and platinum particles, have long been a part of helping artists and photographers lend greater visibility to fine details in drawings and photographs. Plasmonic materials have oscillating electrons that couple efficiently to light. As a result, the materials can be integrated into certain fluids and spread across a surface to make it more visible. Silver iodide, for example, has been used in early photography, in daguerreotypes, to deposit tiny silver particles on surfaces for greater visibility.
By closely characterizing the natures of plasmonic materials in the liquid phase or on solid two-dimensional (2D) surfaces, Fontana and his team found new ways of working with the materials and their highly visible natures and turning them into homogeneous and stable gases. As Fontana explains: “The tiny particles in aerosols have been very difficult to see in real time because they tend to couple poorly to light or are inhomogeneous in size and composition. Now that we can see how they interact with their environment we can look at how they influence cloud formation, convection, and other remote sensing applications.”
Researchers are already looking at how these particles influence the weather as well as how aerosols linked to maritime traffic influence lightning and the intensity of storms at sea. They also hope to understand how they might impact research in microelectronic and medical areas. “It’s fantastic how quickly the team pulled this together,” Fontana said. “We’re excited to make this accessible for other labs for their work.” The U.S. Patent Office designated the measurement instrument for generating and optically characterizing an aerosol as pending patent 110326-US3; work on the research and instrument was funded by the Office of Naval Research (ONR).