Programmable and Emergent Structures in Soft Matter: Chirality, Polarity, and Auto-Origami

软物质中的可编程和紧急结构：手性、极性和自动折纸

• 批准号: 1409658
• 负责人: Robin Selinger
• 金额: $ 37.5万
• 依托单位: Kent State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1409658&HistoricalAwards=false
• 关键词: Programmable; Emergent; Structures; Soft; Matter

Non-technical Summary:This award provides support for theoretical studies of responsive liquid crystal polymers, a form of plastic that spontaneously changes shape under heating or cooling. Rod-shaped liquid crystal molecules bonded to the polymer's main chains are disordered in orientation at high temperature but align at low temperature, inducing the polymer chains to extend in a parallel direction, and as a result the material stretches when cooled. Some materials containing light-sensitive dyes also change shape in response to illumination. A sample prepared with a non-uniform imposed pattern of local molecular orientation, a process known as blueprinting, shows complex shape evolution as the induced stress/strain is not uniform. The blueprinted pattern thus encodes a complex trajectory of movement from an initial state, e.g. a flat thin film, to a final state that is folded, curved, or twisted, a form of programmed auto-origami. Computer simulation studies of this process will explore the mathematical relationship between blueprinted structures and the resulting shape change. These materials have potential application in robotics, light-driven mechanical devices, touch displays, biomedical devices, and switchable surface textures. Related studies will examine shape change, pattern formation, and phase behavior in lipid membranes and liquid crystals. Outreach efforts, including research internships for 60+ high school students and annual science fair for six school districts, attract students to STEM careers and aim to improve the diversity of the STEM workforce.Technical Summary:This award supports theoretical/computational research and education in soft matter physics. It combines computer simulation and fundamental theory to investigate mechanisms of microstructural/shape evolution and pattern formation in soft matter. The proposed theory/modeling studies of orientationally ordered lipid membranes and nematic solids are united by themes of differential geometry, curvature, topological defects, complex ordering and response, topology, and self-assembly. The principal problems to be investigated are: (1) Auto-origami: nematic solids as programmable, stimuli-responsive materials; (2) Lipid membranes: coupling of topological defects and curvature; (3) Phase transitions in liquid-crystal elastomers: kinetic evolution of polydomain structures; (4) Flexoelectricity in liquid crystals: formation of complex modulated phases. In all of these cases, the PI's will collaborate with experimental scientists to compare predictions with experiments on physical and biological systems.This research is connected to fundamental problems in self-assembly, nonlinear elasticity, topological defects, and differential geometry. Potential applications of outcome of this research could include soft actuators, shape control of lipid vesicles for drug delivery, self-assembly of vesicles for photonic crystals, and new liquid-crystal display technologies and switchable surface textures.

非技术总结：该奖项为响应性液晶聚合物的理论研究提供支持，液晶聚合物是一种塑料，在加热或冷却下会自发改变形状。与聚合物主链结合的棒状液晶分子在高温下方向紊乱，但在低温下排列整齐，诱导聚合物链向平行方向延伸，因此材料在冷却时拉伸。一些含有光敏染料的材料也会根据光照改变形状。用局部分子取向的非均匀施加模式制备样品，这一过程被称为蓝图，由于诱导的应力/应变不均匀，显示出复杂的形状演变。因此，蓝图图案编码了从初始状态（例如平面薄膜）到折叠、弯曲或扭曲的最终状态（一种程序化自动折纸形式）的复杂运动轨迹。这一过程的计算机模拟研究将探索蓝图结构和最终形状变化之间的数学关系。这些材料在机器人、光驱动机械设备、触摸显示器、生物医学设备和可切换表面纹理方面具有潜在的应用前景。相关研究将检查脂膜和液晶的形状变化、模式形成和相行为。推广工作，包括为60多名高中生提供研究实习机会，为六个学区举办年度科学博览会，吸引学生从事STEM职业，旨在提高STEM劳动力的多样性。技术概述：该奖项支持软物质物理学的理论/计算研究和教育。它将计算机模拟与基础理论相结合，研究软物质微观结构/形态演化和模式形成的机制。提出的定向有序脂质膜和向列固体的理论/建模研究是由微分几何、曲率、拓扑缺陷、复杂有序和响应、拓扑和自组装等主题联合起来的。要研究的主要问题是：(1)自折纸：向列固体作为可编程的、刺激响应的材料；(2)脂质膜：拓扑缺陷与曲率耦合；(3)液晶弹性体的相变：多畴结构的动力学演化；(4)液晶中的柔性电：复杂调制相的形成。在所有这些情况下，PI将与实验科学家合作，将预测与物理和生物系统的实验进行比较。本研究涉及自组装、非线性弹性、拓扑缺陷和微分几何等基本问题。本研究成果的潜在应用包括软致动器、用于药物传递的脂质囊泡的形状控制、用于光子晶体的囊泡自组装以及新的液晶显示技术和可切换的表面纹理。