Mechanics of Interfacial Assemblies

CBET 1438425本项目研究由小颗粒包裹的液体界面的机械性能。当液体界面上的颗粒数量较多时，颗粒会形成被称为细观结构的排列，这可能会改变界面的机械硬度、渗透性、外观或其他属性。该项目将使用实验、理论和数值计算相结合的方法来展示介观结构的形成如何影响界面的机械性能。覆盖着颗粒的界面出现在广泛的技术和生物应用中，包括用于食品和药物输送的微胶囊配方、采矿作业中的分离以及用于处理水体中油类污染的改进的低毒分散剂。该项目中获得的信息将为科学家和工程师提供新的方法来预测、分析和控制界面的机械性能，从而产生创新和机械坚固的产品。该项目还将支持本科生和研究生在科学或工程领域的职业培训，并将支持与K-12学生和教师的接触。将制造被称为粒子片的粒子涂层界面，并测量其拉伸和弯曲的硬度(模数)。颗粒片材将受到应力或几何变形的影响，以识别三种不同的反应：起皱或屈曲、撕裂或破裂，以及颗粒堆积缺陷的形成，如错位或位错。颗粒片材对单轴压缩的响应将提供弯曲模数。通过拨动施加在薄板上的点状力的响应将提供拉伸模数。通过将颗粒片限制在弯曲的界面上来改变颗粒片的曲率，将阐明褶皱、裂纹和颗粒填充缺陷之间的竞争。该项目的实验和理论活动将导致建立由颗粒组成的薄板的结构松弛相图。

CBET 1438425This project examines the mechanical properties of liquid interfaces that are coated by small particles. When the number of particles on a liquid interface is large, the particles can form arrangements called mesostructures, which can change the mechanical stiffness, permeability, appearance, or other properties of the interface. The project will use a combination of experiments, theory, and numerical calculations to show how mesostructure formation affects mechanical properties of the interface. Interfaces covered with particles appear in a wide variety of technological and biological applications including microcapsule formulations for food products and drug delivery, separations in mining operations, and improved, low-toxicity dispersants for treating oil contamination in bodies of water. The information obtained in this project will provide new methods for scientists and engineers to predict, analyze, and control the mechanical properties of interfaces, which can lead to innovative and mechanically robust products. This project will also support the training of undergraduate and graduate students for careers in science or engineering, and it will support outreach to K-12 students and teachers.Particle-coated interfaces, called particle sheets, will be fabricated and their stiffness (moduli) for stretching and bending will be measured. Particle sheets will be subjected to stress or geometric distortion to identify three distinct responses, wrinkling or buckling, tearing or cracking, and the formation of particle-packing defects such as disclinations or dislocations. The response of a particle sheet to uniaxial compression will provide the bending modulus. The response to point-like forces imposed on the sheet by poking will provide the stretching modulus. Changing the curvature of a particle sheet by confining it on a curved interface will elucidate the competition among wrinkles, cracks and particle-packing defects. The experimental and theoretical activities in this project will lead to the development of a structural relaxation phase diagram for thin sheets composed of particles.