This CAREER project will investigate a class of surficial films in oxide materials that exhibit self-selecting thicknesses of 0.5-5 nanometers. These surficial films, recently discovered as a free-surface counterpart to equilibrium-thickness intergranular films, have compositions and structures that are neither observed nor stable as bulk phases. The temperature/chemistry dependent equilibrium-thickness, composition, and structure (including partial order) of these nanoscale films will be characterized in several model oxide systems using high resolution and scanning transmission electron microscopy in conjunction with other surface analysis methods. The existence of surface phase transitions and electrostatic space-charge will be explored. In a parallel theoretical study, phase-field and lattice-gas models will be developed to simulate the surficial film stability. Successful investigation of equilibrium surficial films as a previously-unrecognized class of ionocovalent adsorbates will enhance multilayer adsorption theories, as well as provide new perspectives for understanding several related interfacial phenomena such as prewetting, premelting, and equilibrium intergranular films. Moreover, the project will make possible exciting applications of these surficial films as two-dimensional nanomaterials in catalysts, sintering, and nano-devices. The research findings will also be treated in the broader context of interfacial science and utilized in materials science education. Education and research integration activities will include 1) developing a series of free, web-based, materials science minicourse in which the results of this project will be utilized as research-based education materials; 2) establishing a high school outreach and research exposure program; and 3) educating, inspiring, and mentoring students while they perform research.
This CAREER project will build the fundamental scientific knowledge for a new class of adsorption and thin-film behaviors on oxide surfaces. It is expected to have a broad impact on several scientific and technological fields including ceramics, surface science, catalysts, and microelectronics. The project integrates research and education. Special effort will be made at the K-12 level to motivate high school students in South Carolina to continue their education at institutions of higher learning. Professional education and enhancement of public scientific understanding are also addressed in the web-based educational subproject, where open and free materials science education resources will be developed for self-learners around the world.
