Precise Control of Polyaniline Nanohelices with Chirality Continuum and Their Correlation on Catalytic Performance

Abstract

Left-and right-handed chiral molecule inducers have been frequently used to guide the formation of chiral nanomaterials with binary chiral shapes. However, the transition of chiral nanomaterials from discrete to continuously tunable chiral shapes is imperative but challenging and will contribute to a deep understanding of the fundamental relations between chiral nanostructures and their chemical properties. This study shows that chiral polyaniline nanohelices (PANI NHs) with similar aspect ratios (∼5.0) but continuously tunable screw pitches (293 to ∞ nm) and tilt angles (33°to 0°) can be fabricated by adjusting the enantiomer excess of S/R-camphorsulfonic acid used as a chiral molecule inducer. After Au nanoparticles were loaded on the surface of chiral PANI NHs, the chiral morphology-dependent catalytic performances of PANI-Au NHs are studied in reduction, oxidation, and enantioselective catalytic reactions, showing that the larger the helical twist degree, the higher the catalytic activity and enantioselectivity of PANI-Au NHs.