Electrorheological properties of polypyrrole prepared by the action of mineral acids on pyrrole

Abstract

Polypyrrole was prepared in high yield by the polymerisation of pyrrole in strongly acidic conditions using hydrofluoric, hydrochloric (at 20 °C and 100 °C), hydrobromic, nitric and orthophosphoric acids. The polymer products incorporated significant amounts of the anion from the acid used. The particulate morphology of the polymer products chiefly consisted of agglomerated µm-sized spheres. The rheological properties of dispersions of polymers prepared from pyrrole using hydrochloric and hydrobromic acids, suspended in 1-chloronaphthalene–l-bromonaphthalene, were found to be electric-field dependent. Fluids prepared from the polypyrrole products derived from hydrofluoric, nitric and orthophosphoric acids did not exhibit an electrorheoloeical response.