Separation of Single-Walled Carbon Nanotubes by Amine-Functionalized Polydimethylsiloxane

Abstract

In the present study, utilizing the selective adsorption characteristic of amine groups, metallic single-walled carbon nanotubes (SWNTs) are selectively removed from the HiPco SWNT mixture arranged on a SiO2/Si substrate using a surface-functionalized polydimethylsiloxane (PDMS) stamp with amine groups for the successful separation of metallic and semiconducting SWNTs. To enhance the separation efficiency, HiPco SWNTs originally dispersed in aqueous solution with sodium dodecyl sulfate (SDS) are arranged in high density on a SiO2/Si using dielectrophoresis, and it is demonstrated that high-yield SWNT separation was possible even with a single stamping process. We find negatively charged SDS predominately exists on metallic SWNTs rather than on semiconducting SWNTs; it strongly combines with positively charged H atoms in amine groups on PDMS and, thus, can be peeled off and separated using an amine-functionalized PDMS stamp together with metallic SWNTs