Ice-Templating Synthesis of Polyaniline Microflakes Stacked by One-Dimensional Nanofibers

In this paper, a facile and environmentally friendly route, an ice-templating method, has been developed to prepare polyaniline (PANI) microflakes stacked by one-dimensional (1D) uniform nanofibers with diameters in the range 22−32 nm. Although the ice-templating method has been used for preparing ultrapure materials with unique structures in recent years, to our knowledge, this is the first report on using the ice-templating method to direct the polymerization of aniline. Platelet-shaped ice crystals with high aspect ratios provide a particularly novel template to microscopically confine PANI microflakes. The concentration of reagents (aniline, H 4 SiW 12 O 40 doping acid, and ferric chloride oxidant) and the growth mechanism of PANI flakes are investigated in our experiment. The structure and morphology of the PANI microflakes are characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) patterns, energy-dispersive X-ray analysis (EDX), and scanning electron microscopy (SEM). The conductivity of the doped PANI microflakes is 0.120 S/cm. The PANI microflakes piled up with nanofibers have super performance in sensitivity, time response, and reversibility to NH 3 .