Experiment Research On The Orientation And Localization Of Carbon Nanotubes

The post-growth method of Carbon Nanotubes (CNTs) is widely applied on the fields of carbon nanotubes construction assembly. It is a manufacture means of Top-Down method. On the other hand, the self-assembled monolayers techniques are important and efficient measures for assembling the nanostructures from Bottom to Up. Excellent properties in mechanics and electronics, carbon nanotubes are becoming the candidate for the next generation nanomaterials of constructing the NEMS (Nano-Electromechanical System). Now the NEMS based on CNTs are paid more attentions and interests. Our works are mainly concentrated on the orientation and location alignment of carbon nanotubes using the methods combined Top-Down and Bottom-Up.First, some researches are done on the structures of carbon nanotubes and fabrication methods. The material qualities of carbon nanotubes may be different caused by the different fabrication methods. The raw materials of carbon nanotubes need to be pure treated by H2SO4 and HNO3. The carbon nanotubes treated by above methods can be easily dispersed into the solvents. Also deep studies are explored on the rheology and electronic properties of carbon nanotubes solution to guide the orientation and localization experiments followed.It is the effective measures for self-assembled technique to fabricate and assembly the nanostructures. Some studies on the APTES (Aminopropyltriethoxylsilane) and OTS (Aminopropyltriethoxylsilane) SAMs are made, respectively, and found that different polar self-assembled monolayers (SAMs) have different adsorption ability to carbon nanotubes. Using MCP (Micro-Contact Print), the different SAMs can be assembled on the same silicon substrate. Then carbon nanotubes can be selectively adsorbed onto the area assembled with amino terminated SAMs. Conclusions above can be applied to the selective adsorption of CNTs.The orientation alignment experiments of CNTs are carried out using gas to drive the CNTs suspension to flow along the silicon substrate. Based on the boundary layer theory and rheology properties, the orientation experiment set-up is designed. The orientation experiments are carried out and the large-scale orientation alignment of CNTs are achieved. As a supplementary, the CNTs orientation alignment using the rotation method is explored. Such method can improve the orientation alignment experiment results effectively.Based on the CNTs selective adsorption experiments, the localization alignment of carbon nanotubes are performed with the help of MCP. The CNTs are selectively adsorbed on the amino terminated self-assembled monolayers (SAMs). Then the orientation and localization alignment methods are combined to implement the orientation and localization alignment of CNTs. Finally the nanostructures are assembled with MWCNTs using methods as described above on the microstructures pre-fabricated.