Enhanced stability of conductive polyacetylene in ladder-like surface-grafted brushes

Abstract

Formation and characterization of polyacetylene-based brushes that exhibit exceptional long term stability in air is presented here. Polyacetylene, structurally the simplest conjugated polymer, exhibits the highest conductivity among conjugated polymers but also very low stability. Both instability and difficulties in processing have ruled out polyacetylene from commercial applications so far. The brushes grafted here from gold via a self-templating surface-initiated method and having a ladder-like architecture showed after iodine doping high directional conductivity reaching up to 10⁻² S cm⁻¹ (measured using conductive atomic force microscopy) that was also practically independent of the grafting density. More importantly, conductivities of the brushes after 6 months storage in air at room temperature were reduced only by one order of magnitude as compared to the initial values. The surface grafting of ladder-like brushes containing polyacetylene chains reported here by addressing the instability and processability problems may again attract interest in this conductive polymer several decades after its discovery.