Electrosynthesis of polyurethane-based core-shell PAn • (+)-HCSA colloids

The formation of core-shell colloidal particles based on polyurethane with a polyaniline coating has been investigated using an electrohydrodynamic processing method. It has been found that stable dispersions of highly optically active colloids can be formed both in the presence and absence of polystyrene sulfonate when one hand of camphorsulfonate is used. In both cases, the optical activity increased upon standing after polymerisation. This was accompanied by transformation from the "tight coil" to "expanded coil" conformation as reflected in changes in the UV-visible spectra upon standing. In all cases, particle size increased with polymerisation time. This was initially due to coating of single particles at shorter times and agglomeration of these into much larger particles at longer times. (C) 2000 Elsevier Science S.A. All rights reserved.