Design and Fabrication of Brochosome-Inspired Infrared Coatings (Tracking No.: FY2019-000067-AS)
Abstract
Surface coatings that can passively or actively control the reflectivity or emissivity of the target surfaces in the infrared regions are of paramount importance to a range of defense applications including night vision and LiDAR technologies, heat-seeking technologies, thermal signature management and camouflage, as well as astronomical sensing. Conventional optical coatings are mainly multilayered structures designed according to optical interference effects and the intrinsic optical absorption characteristics of different materials, which are typically limited by their optical responses to specific electromagnetic spectrum. In the biological world, many natural species, such as chameleons, butterflies, and beetles, utilize micro- and nanoscale architectures to interact with electromagnetic waves in the visible spectrum. Extending the concept of utilizing micro- and nanostructures to interacting with infrared spectrum may lead to a range of novel optical materials with tunable infrared reflectivity and thermal emission characteristics that cannot be replicated by the intrinsic optical characteristics of conventional materials. For example, it has recently been shown that the synthetic counterparts of the leafhopper-produced brochosomes, which are three-dimensional soccer ball-like microscale granules with distributed nanoscale cavities, have the ability to absorb broadband electromagnetic radiation of up to 99 percent of ultraviolet, visible, and near-infrared spectrum. Inspired by the light-absorbing capability of brochosomes, we propose to design and fabricate brochosome-inspired coatings that have tunable reflectivity and emissivity in the near-infrared to far-infrared range through combined numerical and experimental approaches. Specifically, we will perform parametric study to understand the relationship of the synthetic brochosome geometries and the optical reflectivity and emissivity in the infrared range through electromagnetic modelling and simulations. Based on the insights obtained from the numerical simulations, we will fabricate brochosome-inspired coatings and investigate their infrared reflectivity and thermal emission characteristics in air and in encapsulated forms. Scalable manufacturing of the brochosomeinspired coating films will also be developed. Ultimately, the proposed research will establish a solid foundation for the future development of passive and dynamic infrared coatings for various defense applications under a range of operating environments.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 17, 2020
- Source ID
- N000142012095
Entities
People
- Tak-Sing Wong
Organizations
- Office of Naval Research
- Pennsylvania State University
- United States Navy