Site-Specific Selective Bending of Actuators using Radio Frequency Heating

In hazardous or microscale environments, it is valuable to have actuators that can be triggered without a direct connection to a power source and can exhibit site-specific actuation. Thermal actuators use temperature to initiate motion, and prior reports use heat sources such as direct current (DC) power or light, which have drawbacks of a limited movement and complexity in design for selective actuation. It is previously shown that carbon nanomaterials show remarkable heating rates in response to applied radio frequency (RF) fields. Herein, a noncontact, site-specific thermal actuation by using RF heating of carbon nanomaterials is demonstrated. The actuators based on two RF susceptors: carbon black tape and laser-induced graphene (LIG), are shown. The actuator shows stable and reproducible heating and bending over repeated cycles. The heating and bending performance of actuators using Comsol Multiphysics is also simulated. By simply manipulating the field frequency, it is able to create site-specific actuation in two different locations. As a proof of concept, a light emitting diode (LED) switch that can change colors at specific operating frequencies, where actuators are used as a barrier between lasers and receivers, is demonstrated. Such actuators have potential applications in soft robotics, and micromanipulation systems.