Collaborative Research: Using Boundaries to Create and Control Pathways for Photomechanical Actuation

合作研究：利用边界创建和控制光机械驱动路径

• 批准号: 1635926
• 负责人: M Ravi Shankar
• 金额: $ 20万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635926&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Boundaries; Create; Collaborative; Research; Using; Boundaries; Create

This award supports fundamental research into new ways to hold and constrain liquid crystal elastomers that will cause thin sheets to change shape in discrete steps as the sheets are illuminated. Liquid crystal elastomers are a class of polymers that can be tailored to undergo changes in shape when they are illuminated with light, thereby enabling the direct conversion of light into directed mechanical work. An important advantage of using light is that wiring, circuitry, and mechanical contacts are not needed; devices made of these materials can be operated remotely. This property can enable applications in a range of technologies, including light-operated microsurgical tools, display technologies integrated with touch feedback, and robotics that harness light for manipulation. However, the mechanical force generated by these materials is small and the shape change during irradiation with light is difficult to control. The new shape change mechanisms will simultaneously generate fast response times and large forces during the transition between the shapes. Therefore, the results of this research can enable new device architectures and bring these materials closer to widespread application, thereby benefitting the US economy and society. Outreach to underrepresented K-12 students through local Pittsburgh organizations will also be integrated with the research program. Light-driven shape change observed in liquid crystal elastomers can enable a class of next-generation of remotely-driven actuators. This research will explore the interplay between the photomechanical adaptivity and localized constraints applied at the boundary. In particular, this interplay triggers a cascade of discrete transitions from a prior flat state into non-self-similar shapes. Integrated experiments and modeling will be used to understand the interactions between microstructural heterogeneity, boundary conditions, material anisotropy and photostrains on the emergent multimorphism and actuation. The resulting core contribution to mechanics will be the deeper fundamental understanding of the interplay between instabilities and boundary conditions in two-dimensional objects with complex curvature and heterogeneity, using shell and membrane theories from mechanics. The research tasks include synthesis of thin-film specimens, characterization of light-induced mechanical deformation, development of mathematical models, and numerical and analytical analysis of the models. The feedback between experiment and theory will enable the formulation of predictive and accurate models, as well as provide physics-based guidance to the experiments.

该奖项支持针对持有和限制液晶弹性体的新方法的基本研究，这将导致薄板在发光时以离散步骤改变形状。 液晶弹性体是一类聚合物，可以在用光照亮时量身定制以经历形状的变化，从而使光转化为有向机械工作。使用光的一个重要优点是不需要接线，电路和机械接触。这些材料制造的设备可以远程操作。 该属性可以在一系列技术中启用应用程序，包括灯光的微型手术工具，展示与触摸反馈集成的技术，以及可利用操纵光线的机器人技术。 但是，这些材料产生的机械力很小，在光照射期间的形状变化很难控制。在形状之间的过渡期间，新的形状变化机制将同时产生快速的响应时间和较大的力。 因此，这项研究的结果可以实现新的设备架构，并使这些材料更接近广泛应用，从而使美国经济和社会受益。通过匹兹堡当地组织向代表性不足的K-12学生推广也将与研究计划集成。在液晶弹性体中观察到的光驱动形状变化可以使一类远程驱动的致动器的下一代。 这项研究将探讨在边界上应用的光学适应性与局部约束之间的相互作用。 特别是，这种相互作用触发了一系列从先前平坦状态到非相似形状的离散过渡。综合实验和建模将用于了解微结构异质性，边界条件，材料各向异性和在新兴的多态性和驱动上的相互作用之间的相互作用。 最终对力学的核心贡献将是使用机械师的壳和膜理论，对具有复杂曲率和异质性的二维对象中不稳定性和边界条件之间的相互作用的基本了解。 研究任务包括薄膜标本的合成，光诱导的机械变形的表征，数学模型的发展以及模型的数值和分析分析。 实验与理论之间的反馈将使预测和准确模型的制定，并为实验提供基于物理的指导。