Controlled growth of polypyrrole hydrogels

Tailoring the morphology and swelling-shrinking behaviors of the conducting polymer hydrogels is vital to realizing enhanced performance. Here, we demonstrate an effective approach for the controlled growth of polypyrrole hydrogels with both electrical properties and hydrogel characteristics. Under the static synthetic conditions, the polypyrrole nanotubes are self-assembled to form mesoscale networks of the hydrogels. The effect of the kind and amount of the oxidants on the morphology and swelling-shrinking behaviors of the polypyrrole hydrogels is investigated in detail. The strength of polypyrrole hydrogel is enhanced with the increase of the amount of the oxidant. In the case of Fe(NO3)3as the oxidant, the swelling-shrinking properties of the polypyrrole hydrogels are improved due to the more polypyrrole granules as a mesoscale cross-linker on the surface of polypyrrole nanotubes.