Faculty Sponsor's Department:
Photo-thermal actuators are a type of stimuli responsive materials, also known as smart materials, that convert light into mechanical energy. The oscillating materials I studied are liquid crystal networks (LCN) with splay configuration. These thin films can be easily fabricated using commercially available mesogens mixed with dyes that can absorb light and dissipate heat. By irradiating the hinge of a cantilever shaped actuator, continuous oscillation can be achieved due to a feedback loop based on self shadowing. Placing two oscillating films 2mm apart causes the two films to couple and oscillate in phase or out of phase. The mechanism of synchronization was studied and linked to air as the medium for coupling. Under vacuum, these two oscillators show no coupling and move independently to each other. This result shows that the frequency and degree of coupling of the system are dependent on the environment. We hope to take advantage of this phenomenon to make new type of sensors sensitive to surrounding gas. Understanding the dynamics of multi-oscillating LCN systems will hopefully give new opportunities for the development of automated systems with potential interest in soft robotics and sensors.