Theoretic optimisation of microfluidic and magnetic self-assembly of carbon nanotubes

In this reported work, a magnetic and fluidic analysis has been performed to theoretically analyse the self-assembly mechanism of carbon nanotubes (CNTs) and to characterise the assembling environments for the high-density integration of individual CNTs. In previous work by the present author, the residual iron (Fe) catalyst at one end of a CNT was magnetically captured and the captured CNT was aligned along the flow direction by fluid drag force, leading to precise individual integration of CNTs between electrodes. To advance the previous work and technique, theoretic characterisations were executed to optimise the assembling conditions which increased the number of attached CNTs with a high density of integration. For calculating the fluidic force applied to the individual CNT, the slender-body theory was adopted by modelling the CNT as a slender object. Moreover, magnetic simulation was performed to calculate the magnetic force applied to the residual Fe catalysis at one end of the CNT. These simulation results were combined and used to determine the critical height where the fluidic force was equal to the magnetic force. On the basis of these analyses, the array of CNT-assembled electrodes was implemented with a 2 m interval, whereas only a single CNT-assembled electrode was achieved in the previous work. A result of the present work, enables dense integration of the CNT circuit as a highly functional nanodevice.