Growth of hexagonal polyaniline fibers with polyacrylamide pendants

Abstract

A new concept of synthesizing hexagonal polyaniline (PANi) fibers with polyacrylamide (PAAm) pendants in PAAm oligomer (oligo-PAAm) colloid is proposed. The size and morphology of the composite fibers can be controlled by adjusting the synthesis conditions. A possible growth mechanism of the PANi microstructures based on typical PAAm–crystals interactions in a mild aqueous solution is proposed. The amide ligands decorated oligo-PAAm chains are able to coordinate with –C6H4–NH+C6H4NH+–C6H4–NH–C6H4–NH– sections, leading to a lower surface energy and growth along c-directions to form fibriform morphology. The fibers have uniform diameter ranging from 200 to 400 μm, and length varying from several millimeters to 6 cm. Fourier transform infrared measurement indicates that the fiber exhibits a main PANi chain with PAAm pendants, and ultraviolet–visible spectra reveal that the PANi is in high conductive emeraldine state. Acrylamide feed significantly affects the morphology, however, the conductivity and yield of the fiber depend on hydrochloric acid and potassium peroxydisulfate concentrations in the preparation process. The hexagonal composite fibers show an electrical conductivity of 2.2 S·cm−1 and yield of higher than 95%. Polymer-directed crystal growth may provide promising routes to rational synthesis of various ordered organic materials with complex form and structural specialization. POLYM. COMPOS., 35:253–262, 2014. © 2013 Society of Plastics Engineers