CAREER: Nanoscale Surficial Disordered Films: Multilayer Adsorbates in Oxide Ceramics

这个CAREER项目将研究一类具有自选择厚度为0.5-5纳米的氧化材料表面薄膜。这些表面膜，最近被发现是平衡厚度晶间膜的自由表面对应物，其成分和结构既不像体相那样观察到也不稳定。这些纳米级薄膜的温度/化学依赖平衡-厚度，组成和结构（包括偏序）将在几种模型氧化物系统中使用高分辨率和扫描透射电子显微镜结合其他表面分析方法进行表征。探讨表面相变和静电空间电荷的存在性。在平行理论研究中，将建立相场和晶格-气体模型来模拟表面膜的稳定性。平衡表面膜作为一种以前未被认识的离子共价吸附剂的成功研究将增强多层吸附理论，并为理解一些相关的界面现象，如预润湿、预熔和平衡晶间膜提供新的视角。此外，该项目将使这些表面薄膜作为二维纳米材料在催化剂、烧结和纳米器件中的应用成为可能。研究结果还将在界面科学的更广泛背景下进行处理，并用于材料科学教育。教育和研究的整合活动将包括：1)开发一系列免费的、基于网络的材料科学迷你课程，其中本项目的成果将用作基于研究的教育材料；2)建立高中外展和研究曝光计划；3)在学生进行研究时对他们进行教育、激励和指导。这个CAREER项目将为氧化物表面的新型吸附和薄膜行为建立基础科学知识。预计它将对陶瓷、表面科学、催化剂和微电子等几个科技领域产生广泛的影响。该项目将研究与教育相结合。将在K-12阶段做出特别努力，以激励南卡罗来纳州的高中生继续在高等院校接受教育。专业教育和提高公众对科学的理解也在基于网络的教育子项目中得到解决，在这个子项目中，将为世界各地的自学者开发开放和免费的材料科学教育资源。

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.