This US/France collaborative project funded by the Division of Materials Research will focus on fundamental studies of a novel class of sustainable reactive composite nanolaminates containing a metal (commonly aluminum) and metal oxide (commonly copper oxide, iron(III) oxide, and zinc oxide). The materials attracted great interest in the energetic material community since they are characterized by a high energy and power density (superior to supercapacitors), and are low cost and safe, useful for micro-thermal sources, micro-actuators and enablers for environmentally clean primers, miniature safe detonators, in-situ welding and soldering, and also chemical neutralization agents. Yet, interfaces play a critical role during the synthesis and the utilization of these reactive layered nanostructures. The formation of interfacial layers is not only poorly understood but uncontrolled at present. A fundamental understanding of the formation and role of these aluminum/metal-oxide interfacial layers would not only bring control of such systems, but also be transformative for fundamental and practical advances in this field. This project aims at developing an atomic-level understanding of the interface formation process between Aluminum/Metal-oxide by combining in-situ spectroscopy and imaging with Density Functional Theory calculations for a variety of deposition methods. To this end, model surfaces and atomically precise deposition methods (e.g. atomic layer deposition) will be used to derive detailed atomic information, in combination with nanopatterning processes to quantify the contribution of the interfacial layers for both the reaction kinetics and the stability at low temperatures. Deposition/synthesis issues specifically associated with highly reactive materials are unraveled by the development of novel theoretical methods coupled with extensive and unique in situ characterization methods. Thermal characterization techniques combustion tests combined with high resolution imaging and x-ray diffraction will be used to quantitatively evaluate the role of such interfaces in operating conditions. This project constitutes a first step in understanding the role of interfaces in reactive hetero-structures. Aluminum, copper, iron and zinc are all widely available and recyclable resources and common materials in microelectronics. These Aluminum/metal oxide nanolaminates are therefore sustainable, totally safe and not toxic for the environment and human health, requiring no hazardous substances and releasing no pollutant chemicals for their productions. The social, environmental and economic benefits are clear since these nanomaterials and nanostructures will contribute to reducing the use of many dangerous and polluting energetic materials (containing lead salt for example or synthesized using polluting chemistry).
NON-TECHNICAL SUMMARY: Reactive materials are critical for defense and energy. Ultra-thin layers of reactive materials, called reactive composite nanolaminates (e.g. aluminum and copper oxide), have attracted great interest in the energetic material community since they are characterized by a high energy and power density and are low cost and safe, useful for miniature thermal sources, actuators, detonators, and chemical neutralization agents. Most investigations have focused on the relationship between the structure and thermal properties of these reactive and metastable nanolaminates. Yet, interfaces play a critical role during their synthesis and utilization. The nature of interfaces is not only poorly understood but uncontrolled at present. A fundamental understanding of the formation and role of these interfacial layers would not only bring control of such systems, but also be transformative for fundamental and practical advances in energy and defense fields. By combining growth, characterization and theoretical studies, this project provides the foundation towards the design of future tailored reactive nanostructures by interface optimization using atomically precise technologies. It establishes a bridge between the fields of reactive materials and solid state and material chemistry. It provides a multidisciplinary environment for the students, besides the benefits of cultural exchange. There is a focused integration of the research topic into educational programs (graduate courses, tutorials, certificates) both in the US and in France. At UT Dallas, this project engages underrepresented minority and women graduate students, and is a backbone for targeted outreach within the greater Dallas area. It supports existing programs developed by the UT Dallas Office of Diversity and Community Engagement, and programs to mentor and engage undergraduates in research such as the Academic Bridge and the Louis Stokes Alliances for Minority Participation programs.
