Highly Aligned Carbon Nanotube‐Based Bi‐Material Microactuators with Reduced Intertube Slipping

Abstract Bi‐material microcantilevers have been widely used as both thermal sensors and thermal actuators. Carbon nanotubes (CNT) are prominent candidates for bi‐material actuators due to the negative coefficient of thermal expansion (CTE) at the axial direction that allows for higher thermal sensitivity. However, CNT‐based actuators generally suffer not only from intertube slipping due to weak interactions between the assembled CNTs but also from poor control over orientation assembly. To address these challenges, a new class of closely packed, highly aligned CNT microcantilevers reinforced by ceramic interlocking is here proposed, followed with deposition of Al thin film to form the bi‐material actuators. The investigations of the mechanical properties and thermal response of CNT microcantilevers indicate that the slipping between the tubes limits both the strength and the thermal sensitivity of the bi‐material microcantilevers. Intertube deposition of Al₂O₃ as ceramic interlocking is used to reinforce the binding strength between the tubes, and increases in the mechanical strength as well as thermal sensitivity of the microcantilevers have been achieved.