A π-conjugated polymer gelator from polyfluorene-based poly(tertiary alcohol) via the hydrogen-bonded supramolecular functionalization

The supramolecular approach of π-conjugated polymers imparts excellent self-assembly behaviour to construct organogels and simultaneously affords superstructured thin films, which allow for uncovering structure-function relationships. Herein, a polyfluorene-based poly(tertiary alcohol), poly(9-(4-(octyloxy)phenyl)-2,7-fluoren-9-ol) (PPFOH), has been synthesized to investigate the organic solvent effect on the gelation at room temperature. The driving force of hydrogen bonding and π-π stacking interactions in the aggregate processing of PPFOH has been investigated using nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and photoluminescence (PL). Aggregated structures of PPFOH in gelation solvents have been correlated with the characteristic emission peak at 440 nm in PL spectra. Large effects of the number molecular weight (M_n) on critical gel concentration (CGC) and green emissions of the organogels and nanostructured thin films have been observed. Finally, the emission colour of PPFOH from supramolecular thin films can be tuned flexibly from blue to yellow via selecting different types of solvent and M_n, which are promising approaches to control the optoelectronic functionalities of supramolecular π-conjugated polymers with potential applications in organic thin film electronics, optoelectronics and mechano-electronics.