Conformationally switchable TTFV–phenylacetylene polymers: synthesis, properties, and supramolecular interactions with single-walled carbon nanotubes

Abstract

A series of π-conjugated polymers made up of tetrathiafulvalene vinylogue (TTFV) and phenylacetylene repeat units was synthesized and investigated as supramolecular hosts for non-covalent functionalization of single-walled carbon nanotubes (SWNTs). Adopting a folding conformation in the neutral state, these polymers can effectively interact with individual SWNTs forming supramolecular complexes with good solubility in organic solvents. Responding to certain external chemical stimuli (e.g., oxidation or protonation), however, the polymers change their molecular shapes into a linear structure driven by the formation of TTFV cations and hence result in reversible dissociation of the polymers from SWNTs. Such a process allows the efficient releasing of pristine SWNTs from polymer dispersants. The detailed polymer–SWNT interactions and relevant selectivity for certain types of SWNTs were examined by various spectroscopic analyses. Intriguing bulk materials, such as “bucky gels” and conductive “bucky films”, were obtained from the polymer–SWNT composites and their structural and physical properties were characterized as well.