Spectroscopic analysis of two distinct equilibrium states for the exchange reaction of sodium cholate and oligo-DNA on single-walled carbon nanotubes

Abstract

Understanding the quantitative analysis of the transition adsorption structures of molecules on single-walled carbon nanotubes (SWNTs) is of importance from the point of view of both fundamental science and applications of nanotubes. Absorption spectroscopy reveals that two different equilibrium states are existent for the exchange reaction of sodium cholate (SC) and oligo-DNA (single-stranded 20-mer cytosine) on SWNTs. This is derived from the transitions of the adsorption structures of different chirality-types of SWNTs and SC/DNA at certain SC concentrations below the critical micelle concentration of SC.