Abstract
Summary: Water‐processable conducting polyaniline derivatives (PANIs), such as polyaniline (PANI), poly(o‐methylaniline) and poly(o‐methoxyaniline), were synthesized by in situ chemical polymerization of the corresponding achiral monomer in the presence of the novel chiral polymeric template, chondroitin sulfate. The resulting conducting PANIs were doped and complexed with chondroitin sulfate (CHS) to form intertwined intermacromolecular complexes of PANIs‐CHS, which was confirmed by UV‐vis and FTIR spectroscopy. The induction of the excess one‐handed helical structure into PANIs was confirmed by circular dichroism (CD) spectroscopy with the characteristic bisignate bands at approximately 400 and 450 nm for the emeraldine salt. The effect of ionic strength was investigated on the formation of the intertwined PANI‐CHS complex and the induction of chirality into PANI by adding NaCl to the reaction solution. The CD spectral change of PANI‐CHS in the cycle of dedoping and redoping was also studied, and it was found that intermacromolecular complexation helps to stabilize the chiral conformation in PANI against racemization. Interestingly enough, it was found that optically active PANI‐CHS exhibited pH‐sensitive chiroptical properties. A study of the conductivity, electrochemical activity and the chiroptical properties in different redox states of PANIs provided proof for their use as chiral electrode and electroactively chiral material.
Structure of the complexes of PANIs‐CHS.
magnified imageStructure of the complexes of PANIs‐CHS.