Polymers for Light-Activated Mechanical Actuators

用于光激活机械致动器的聚合物

• 批准号: 1435489
• 负责人: M Ravi Shankar
• 金额: $ 34.68万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1435489&HistoricalAwards=false
• 关键词: Polymers; Light; Activated; Mechanical; Actuators

Polymers composed of molecular segments that can distort when irradiated with light offer a framework for directly converting light into mechanical work. Such materials can be used to engineer new classes of mechanical actuators that are triggered and controlled exclusively with light. One of the more promising light-responsive polymers being studied can generate significant forces upon irradiation with light but is plagued by slow actuation speeds. This award will support fundamental research into the effect of the molecular structure on the photomechanical properties for liquid crystalline copolymers. The insights that emerge can spawn a new class of polymers that could be deployed in systems over a range of length scales where contactless actuation could be enabled such as "soft machines", integrated optomechanical devices, optically-driven microfluidics and microrobots.This research will test the hypothesis that in azobenzene-functionalized liquid crystal polymers (ALCP), controlling the structure of the flexible spacer in mesogenic azobenzene-functionalized crosslinkers can modulate photomechanical actuation and help realize step-changes in actuation rates, work densities and photomechanical stresses. To study this, acrylate-based crosslinking mesogens with azobenzene-group in the rigid core and flexible spacers of various chain lengths will be synthesized. Using these, a range of liquid crystal polymer films will be created, their photomechanical actuation will be measured and their utility in actuators will be examined. During these studies, the physical underpinnings of inducing/erasing photomechanical strains as a function of intensity and polarization of actinic light will be examined. Ultimately, customized nematic directors will be engineered to enable new actuation modes and set the foundation for novel photomechanical machine elements.

由分子片段组成的聚合物在用光照射时可能会变形的分子段提供了一个直接将光转化为机械工作的框架。此类材料可用于设计新的机械执行器类别，这些机械执行器仅由光触发和控制。所研究的更有前途的轻度响应性聚合物之一可以在光线照射后产生重要的力，但由于驱动速度缓慢而困扰。该奖项将支持对分子结构对液晶共聚物光学特性的影响的基础研究。出现的见解可以产生一类新的聚合物，这些聚合物可以在一系列长度范围内部署在系统中，在这些范围内可以启用无接触式驱动，例如“软机器”，集成的光学机械设备，光学驱动的微流体和微驱动的微动物。介质偶氮苯官能化的交联器中的垫片可以调节光机械驱动，并有助于实现致动率，工作密度和光学应力的逐步变化。为了研究这一点，将合成基于丙烯酸酯的交联中胶，并在刚性核心中与偶氮组中的偶氮组和各种链长度的柔性垫片合成。使用这些，将创建一系列液晶聚合物膜，将测量它们的光学致动，并将检查其在执行器中的效用。在这些研究中，将检查诱导/擦除光机械菌株的物理基础，这是阳光光的强度和极化的函数。最终，定制的nematic导演将被设计为启用新的驱动模式，并为新型的光学机器元素奠定了基础。