Single-Walled Carbon Nanotubes (SWNTs) exhibit a number of unique mechanical, thermal, and electronic properties that render them useful for numerous applications, ranging from molecular electronics to nano-scale construction materials.  Although these numerous potential applications can have a significant impact on future technologies, the commercial exploitation of SWNTs has, thus far, been extremely limited.  The highly insoluble nature of these materials is one of the major limitations to their applications, as they cannot be manipulated in solution at practical concentrations using any known solvents.  In addition, the presence of both metallic and semiconducting SWNTs within all commercially available samples poses a major challenge in electronic applications.  Supramolecular functionalization of SWNTs provides a versatile method to address many of these limitations.  Specifically, the p-stacking interactions between conjugated polymers and SWNTs has been proven effective not only in dispersing individual nanotubes in a variety of solvents, but also in selectively interacting with semiconducting SWNTs.  However, the selectivity of this polymer-SWNT interaction is still poorly understood, and requires improvement.  Thus, investigation of new polymer structures that exhibit selective interactions with different nanotube types and diameters is warranted.  We have devoted significant effort toward developing an understanding of the subtle impact that polymer structure has on nanotube selectivity, and have designed new polymers that can bind and release SWNTs upon application of a stimulus.  Specifically, we have prepared high molecular weight polycarbazoles that exhibit selectivity for semiconducting SWNTs, but this selectivity is dependent on polymer molecular weight.  In addition, a copolymer of vinylogous tetrathiafulvalene and fluorene was found to exhibit selective interactions with SWNTs. These interactions could be eliminated upon protonation of the polymer with trifluoroacetic acid, which causes a conformational change in the polymer backbone, and results in polymer desorption.

Interactions of p-conjugated polymers with single-walled carbon nanotubes

248th National Meeting (2014)

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