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.

由分子链段组成的聚合物在受到光照射时会变形，这为直接将光转化为机械功提供了一个框架。这种材料可以用来设计新型的机械致动器，这些致动器仅由光触发和控制。正在研究的一种更有前途的光响应聚合物在用光照射时可以产生显著的力，但受到驱动速度缓慢的困扰。该奖项将支持对液晶共聚物的分子结构对光机械性能的影响的基础研究。出现的见解可以产生一类新的聚合物，这些聚合物可以部署在一系列长度尺度的系统中，其中可以实现非接触式驱动，例如“软机器”，集成光机械设备，光学驱动微流体和微机器人。这项研究将测试假设，在偶氮苯官能化液晶聚合物（ALCP）中，在介晶偶氮苯官能化交联剂中控制柔性间隔物的结构可以调节光机械致动并有助于实现致动速率、工作密度和光机械应力的阶跃变化。为了研究这一点，将合成在刚性核中具有偶氮苯基团和各种链长的柔性间隔基的丙烯酸酯基交联液晶基元。使用这些，一系列的液晶聚合物薄膜将被创建，他们的光机械致动将被测量和他们的效用在致动器将被检查。在这些研究中，诱导/擦除作为光化光的强度和偏振的函数的照相机械应变的物理基础将被检查。最终，定制的微控制器将被设计成能够实现新的驱动模式，并为新颖的照相机械元件奠定基础。