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

非技术概述：该奖项为响应性液晶聚合物的理论研究提供支持，液晶聚合物是一种在加热或冷却时自发改变形状的塑料形式。与聚合物主链结合的棒状液晶分子在高温下取向无序，但在低温下排列一致，导致聚合物链沿平行方向延伸，因此材料在冷却时会拉伸。一些含有光敏染料的材料也会因光照而改变形状。由于诱导应力/应变不均匀，用局部分子取向的非均匀施加模式制备的样品，即所谓的蓝图绘制过程，显示出复杂的形状演变。因此，蓝印图案编码了从初始状态(例如平板薄膜)到折叠、弯曲或扭曲的最终状态的复杂运动轨迹，这是一种编程的自动折纸形式。对这一过程的计算机模拟研究将探索蓝图结构和由此产生的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。相关研究将检查脂膜和液晶中的形状变化、图案形成和相行为。外展工作，包括60多名高中生的研究实习和六个学区的年度科学博览会，吸引学生进入STEM职业生涯，旨在提高STEM劳动力的多样性。技术总结：该奖项支持软物质物理方面的理论/计算研究和教育。它将计算机模拟和基础理论相结合，研究软物质中微结构/形状演化和图案形成的机制。所提出的定向有序类脂膜和向列相固体的理论/模型研究通过微分几何、曲率、拓扑缺陷、复杂的有序和响应、拓扑和自组装等主题来统一。要研究的主要问题是：(1)自动折纸：向列型固体作为可编程的刺激响应材料；(2)类脂膜：拓扑缺陷和曲率的耦合；(3)液晶弹性体中的相变：多域结构的动力学演变；(4)液晶中的柔性电性：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。这项研究与自组装、非线性弹性、拓扑缺陷和微分几何等基本问题有关。这项研究成果的潜在应用可能包括软致动器、用于药物输送的脂囊的形状控制、用于光子晶体的囊泡的自组装、以及新的液晶显示技术和可切换的表面纹理。

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.