Photo-Aligning Molecular Orientations in Liquid Crystal Polymers into Complex Patterns for Programmable Origami

受日本折纸艺术的启发，程序化折纸正在成为一种通过自动折叠二维材料来制造三维物体的新途径。要实现程序化的折纸，一个可编程的小尺寸折叠机构是关键，因此对折纸的要求很高。液晶聚合物是含有棒状或盘状分子单元的弱交联聚合物。当这些分子单元以非均匀的方向排列时，液晶聚合物可以在温度和光等外部刺激的触发下自我变形。该奖项支持基础研究，以开发在小尺寸复杂图案中对齐分子取向所需的技术，并就如何设计分子取向图案以实现所需的三维微结构获得基本了解。三维微结构在传感器、执行器、药物输送和光子器件等各种工业应用中具有重要的应用价值。这项研究的结果应该有助于美国经济，造福社会。这项多学科的研究为研究生和本科生提供了一个很好的机会，让他们掌握光子学、液晶科学与技术、纳米制造和数值建模方面的知识和技能，并通过让少数族裔和高中生参与进来来增强多样性。程序化折纸承诺通过二维材料或结构的自折叠来制造奇异的三维微结构和纳米结构。该项目旨在开发在液晶聚合物薄膜的分子取向领域中印记折叠轨迹的能力。它将研究一种新的光图案化技术来确定复杂的分子取向顺序。它将对分子取向和自折叠过程之间的关系有一个基本的理解。研究团队将(1)为所需的分子取向图案设计、模拟、制造和表征等离子体光掩模；(2)开发用于曝光光取向材料的光学曝光系统；(3)设计、建模和制造嵌入分子取向有序的液晶聚合物薄膜或微结构，并表征其在外部刺激下的形状演变。所提出的光刻蚀技术在以下几个方面具有优势：大规模图案化能力、单次曝光和放大可行性。这项研究将产生产生自折叠和扭曲微结构和可编程三维微/纳米制造的基本理解和新技术。

As inspired by the Japanese art of paper folding, programmed origami is emerging as a new avenue towards manufacturing three-dimensional objects via autonomous folding of two-dimensional sheets of materials. To realize the programmed origami, a programmable folding mechanism at the small length scales is the key and thus in high demand. Liquid crystal polymers are weakly cross-linked polymers incorporated with rod or disk-like molecular units. When these molecular units are aligned in non-uniform directional patterns, the liquid crystal polymers can be triggered to self-deform by external stimuli such as temperature and light. This award supports fundamental research to develop the needed technology for aligning the molecular orientations in complex patterns in small length scales and to gain basic understanding on how to design molecular orientation patterns to achieve desired three-dimensional microstructures. Three-dimensional microstructures are highly desired in a variety of industrial applications such as sensors, actuators, drug delivery and photonic devices. The outcome from this research should contribute to the U.S. economy and benefit society. This multidisciplinary research provides a great opportunity to educate graduate and undergraduate students with knowledge and skills in photonics, liquid crystal science and technology, nanomanufacturing and numerical modeling, and to enhance diversity by involving minority and high-school students.Programmed origami promises manufacturing of exotic three-dimensional micro and nanostructures by self-folding of two-dimensional materials or structures. This project aims to develop capabilities to imprint folding trajectories of liquid crystal polymer films in their molecular orientation fields. It will study a novel photo-patterning technique for defining complex molecular orientation order. It will develop a basic understanding of the relationship between molecular orientation and self-folding processes. The research team will (1) design, simulate, fabricate and characterize plasmonic photomasks for desired molecular orientation patterns; (2) develop an optical exposure system for exposing photoalignment materials; and (3) design, model and fabricate liquid crystal polymer films or microstructures with embedded molecular orientational orders and characterize their shape evolution under external stimuli. The proposed photopatterning technique is advantageous in several aspects: capability of large scale patterning, single exposure and scaling-up feasibility. This research will yield both fundamental understanding and new technologies to produce self-folding and twisting microstructures and programmable three-dimensional micro/nanomanufacturing.