Influence of added hydrogen bonding agents on the chiroptical properties of chiral polyaniline

The chiroptical properties of optically active polyaniline PAn.(−)-HCSA emeraldine salt (ES) products in NMP are stabilised by the presence of potential H-bonding additives such as l-arginine, l-tyrosine, l-alanine, l-valine, and glycine in the precursor emeraldine base/NMP solution prior to acid doping with (R)-(−)-10-camphorsulfonic acid. The stabilisation, i.e. absence of partial solvent-induced deprotonation of the ESs to emeraldine base is attributed to H-bonding interactions between the amino acids and the precursor emeraldine base.