Carbon Nanotube Thin Film Coating for Improved Thermal Management in Piezoceramic Sheet Actuators

Minimally intrusive carbon nanotube coatings are used to demonstrate improved thermal management in piezoceramic actuators. Because of their nanoscale cylindrical structure, carbon nanotubes provide an order of magnitude increase in the exposed surface area compared to the uncoated piezoceramic sheet. This along with their excellent thermal conductivity allows the nanotube coating to act as a heat sink, drawing energy away from the bulk piezoceramic material and dissipating it to the atmosphere. Reduced self-heating of the actuator minimizes capacitive losses and reduces actuator power consumption. To demonstrate the concept, carbon nanotube films are deposited on the surfaces of 0.025 cm thick, commercially available PZT-5H sheets. Two types of carbon-based nanostructures are used to construct the coatings - (1) fluorine functionalized single-walled nanotubes (F-SWNTs) and (2) multiwalled nanotubes (MWNTs). The F-SWNT coating performs better than the MWNT coating and gives up to 40% reduction in surface temperature and 25% reduction in power consumption compared to the baseline uncoated actuator (for the same induced-strain level).