Fundamental Study of Photo-Thermo-Mechanical Actuation in Carbon Nanotubes and their Composites

该项目建议开发一类新的光致动活性复合材料，与传统致动器相比，它有可能提供几个数量级的行程和力能力增加。执行器将通过将碳纳米管添加剂渗透到主体结构矩阵中来构建。纳米管的驱动机制与量子约束效应在纳米管中心核中产生的能量捕获有关，量子约束效应产生了强烈的热量；纳米管的加热引起键膨胀，导致纳米复合材料中的拉伸应变。与这些新材料有关的几个基本问题将被系统地处理和回答。这些包括：(1)光激活信号的最佳波长和强度（功率）是什么；(2)纳米管的几何形状和形貌对光响应的影响；(3)研究纳米管取向和纳米管-基质界面耦合的影响；(4)建立多尺度热力学模型来预测执行器的响应，并对这些模型进行实验验证；(5)将优化后的纳米复合材料执行器的受力、行程、频响和驱动功率要求进行量化，并与工业上使用的传统执行器进行比较。这一研究成果将有助于开发紧凑、轻量化、高权威的光致活性复合材料。重要的是，通过将最小侵入性碳纳米管驱动元件渗透到宿主结构矩阵中，可以直接将驱动能力设计到感兴趣的结构中。从降低复杂性、重量和提供紧凑性的角度来看，这种驱动方案是理想的，并且可以在最小的重量损失下实现大的形状变化和变形能力。

This project proposes to develop a new class of photo-actuated active composite materials that show potential to offer several orders of magnitude increase in stroke and force capability compared with traditional actuators. The actuators will be constructed by infiltrating carbon nanotube additives into a host structure matrix. The actuation mechanism is related to energy entrapment in the central core of the nanotube due to quantum confinement effects which generates intense heat; the heating of the nanotube causes bond expansion resulting in an extensional strain in the nano-composite. Several fundamental questions related to these new materials will be systematically addressed and answered. These include: (1) what is the optimal wavelength and intensity (power) of the photo-activation signal; (2) what are the effects of the nanotube geometry and morphology on the photo-response; (3) the effect of nanotube alignment and nanotube-matrix interfacial coupling will be investigated; (4) multiscale thermo-mechanical models will be developed to predict the actuator response and these models will be validated experimentally; (5) the force, stroke, frequency response and actuation power requirements of the optimized nano-composite actuators will be quantified and compared with traditional actuators used by industry.The outcome of this research can lead to the development of compact, light-weight and high authority photo-actuated active composite materials. Importantly the actuation capabilities can be directly engineered into the structure of interest by infiltrating minimally intrusive carbon nanotube actuation elements into the host structure matrix. Such an actuation scheme is ideal from the point of view of reducing complexity, weight and providing compactness and could enable large shape changes and morphing capability with minimal weight penalty.