Triptycene-based fluorescent polymers with pendant alkyl chains: interaction with fullerenes and morphology of thin films

We report unique triptycene-based alternating copolymers bearing long alkyl chains as pendants. Syntheses utilized 2,6-diethynyltriptycene and appropriate alkyloxyarene monomers polymerized via Sonogashira cross-coupling reaction to yield triptycene-based poly(phenylene ethynylene)s. Resulting polymers are soluble in organic solvents and were characterized using various techniques. Experimental results suggest the polymers are thermally stable and fluorescent. The fluorescence emission is quenched in the presence of fullerenes (C ₆₀ and C ₇₀ ) suggesting strong host–guest interactions. The magnitude of the binding constant between the polymers and these fullerenes was determined to be of the order of 10 ⁵ mol L ⁻¹ . The effects of chain length on the morphology and wettability of the polymers on silicon substrates were studied using atomic force microscopy. Three distinct dewetting patterns, i.e. spherical domains, fractal structures and ring structures, were observed with variation in the pendant chain length. This ability to control the thin-film morphology of the polymers may have potential technological applications, which include but are not limited to sensors, fluorescent coatings and organic electronics.