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

Rensselaer Polytechnic Institute, Troy NY

Investigators

Abstract

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.