Novel processes to reinforce the piezoelectric actuator interface with carbon nanotubes

A study was performed to develop a novel technique to enhance the bond strength between a piezoelectric (PZT) actuator and a hosting structure. The bond interface has been considered to be a critical linkage between the structure and the surface-mounted actuators. The loss of interface integrity can have a detrimental effect on the performance of the PZT actuators. The key feature of the proposed technique is to embed a high-density array of oriented carbon nanotubes (CNTs film) into the adhesive layer between the structure and the actuators to enhance the interfacial strength. This presentation focuses primarily on the two fabrication techniques that were developed during the investigation: one is to grow the CNTs directly on the PZT surface at elevated temperatures and the other is to grow the CNTs film on a substrate and then transfer it into the bonding layer at significantly lower temperatures. The latter method is a cost-effective and easy technique which has the potential to be used for structural (as the one proposed here) and for high-performance electronic applications. Through a microscopic examination of the adhesive, it was found that CNTs were uniformly dispersed and aligned into the bonding adhesive. Mechanical tests were performed to investigate the shear strength of the adhesive layer with the embedded CNTs film. Preliminary results show that an increase of the bondline strength up to nearly 300% could be achieved. However a wide data dispersion was also observed and might be attributable to the ratio between the length of the CNTs and the actual PZT-structure gap [1].