Carbon nanotube micropatterns and cantilever arrays fabricated with layer-by-layer nano self-assembly

The two-dimensional (2D) microstructures and three-dimensional (3D) cantilever arrays based on single-walled carbon nanotube (SWNT) multilayer were fabricated by combining electrostatic layer-by-layer (LbL) nano self-assembly, microlithography, and lift-off. The combinative technique provides a simple, effective, low-cost, and low-temperature fabrication method with a short processing time. The 2D SWNT micropatterns with a feature size of 5 μm were fabricated and characterized. The thickness of a (PDDA/SWNT) bi-layer was measured approximately as 76 Å. SWNTs were randomly deposited on the substrate, and they were interconnected and formed as a dense network. To investigate the potential applications of SWNTs, magnetic cantilever arrays formed with SWNTs, iron oxide (Fe₂O₃) nanoparticles, and polyelectrolytes were developed. A modified lift-off process was developed to provide additional protection for the cantilever arrays. Due to the outstanding mechanical properties of the SWNTs, the fabricated cantilevers are very strong and highly flexible. The cantilever arrays can be used in applications such as biosensors and microvalves.