ERI: Engineering self-assembled responsive materials by employing light-driven shapeshifting of colloidal particles

能够响应环境刺激而改变形状的微观响应性材料具有许多变革性的应用。由于高分辨率3D打印机等昂贵工具的成本以及目标3D形状多样性的限制，当前制造响应性微结构的技术面临着巨大的挑战。该奖项将调查一种基于自组装工艺的廉价替代制造方法的潜力。在自组装过程中，材料的小积木在没有人工干预的情况下自行组织成一个功能结构。通过使用响应性积木，自组装结构的形状可以根据需要进行重新配置。由于自组装提供了积木级别的材料响应以及按需组装和拆卸的灵活性，因此它是解决小规模响应性材料设计的工程挑战的一个有前途的候选方案。这一奖项将提供机会，将CSUF(一家拉美裔服务机构)的本科生和硕士学生培养成高技能的研究人员和未来的工程研究领导者。它还将让更广泛的社区参与尖端软材料研究。对光作出反应而改变形状的胶体粒子将被用于研究响应性的自组装，重点是通过粒子形状的局部调整来塑造全球结构。将开发一种新的实验系统，允许在胶体组件上进行静态和动态图案化照明。该奖项的具体目标是(1)检验有序胶体晶体可以通过位错的发射和迁移来形成的假说，以及(2)研究无序胶体团簇的形状移位。此外，还将建立一个数值模型，以了解胶体相互作用的范围和强度对变形动力学的影响。到目前为止，响应性自组装的实验只在全局形状重新配置的背景下进行研究。该奖项将允许测试理论预测，该预测表明对局部颗粒形状的控制将导致有趣的全球行为，应用于缺陷工程、胶体机器人和活动物质研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Microscopic responsive materials that can change their shapes in response to stimuli from the environment have many transformative applications. The current technology of manufacturing responsive microstructures faces significant challenges due to the cost of expensive tools, such as high-resolution 3D printers, and limitation in the diversity of target 3D shapes. This award will investigate the potential of an inexpensive alternative manufacturing method based on self-assembly process. In a self-assembly process, the small building blocks of a material organize themselves into a functional structure without human intervention. By using responsive building blocks, the shape of a self-assembled structure can be reconfigured on demand. Because self-assembly provides access to the material response at a building-block level and the flexibility to assemble and disassemble on demand, it is a promising candidate for solving the engineering challenges of responsive material design at small scales. This award will provide opportunities to train undergraduate and Masters’ students at CSUF (a Hispanic-serving Institution) into highly skilled researchers and future leaders of engineering research. It will also engage the broader community in cutting-edge soft materials research. Colloidal particles that change their shape in response to light will be employed to investigate responsive self-assembly, with a focus on shaping the global structure using local tuning of particle shapes. A new experimental system will be developed that allows for static and dynamic patterned light illumination on colloidal assemblies. The specific goals of this award are (1) to test the hypothesis that ordered colloidal crystals can be shaped through emission and migration of dislocations, and (2) to investigate shapeshifting of disordered colloidal clusters. In addition, a numerical model will be developed to understand the impact of colloidal interaction range and strength on the shapeshifting dynamics. To date, experiments on responsive self-assembly have been studied only in the context of global shape reconfiguration. This award will allow testing of theoretical predictions suggesting that control over local particle shapes will lead to intriguing global behavior with applications in defect engineering, colloidal robotics, and the study of active matter.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.