Hollow Microstructured Polyaniline Prepared Using Cuprous Oxide Crystals as Templates

Summary: Hollow octahedrons or microspheres of polyaniline (PANI) were successfully prepared using cuprous oxide (Cu 2 O) crystals as new templates in the presence of H 3 PO 4 and ammonium peroxydisulfate as a dopant and an oxidant, respectively. Interestingly, the hollow octahedrons (in the reduced form with a conductivity of <10 −8 S · cm −1 ) could transform into conductive microspheres (in the emeraldine salt form with a conductivity of 10 −2 S · cm −1 ) when the [APS]/[An] ratio was changed from 1:1 to 2:1. Compared with the common template reported, Cu 2 O crystal is not only a new type of template in terms of both shape and quality, but also omits post‐treatment due to soluble Cu 2+ formed by the reaction of Cu 2 O with APS during the polymerization process. The universality of Cu 2 O as a template to prepare microstructured PANI was proved by changing the morphology of the Cu 2 O crystal. It was found that the morphology, oxidation and protonation state of PANI microstructures prepared with octahedral Cu 2 O as the template were affected by the [Cu 2 O]/[An] and [APS]/[An] ratio due to the competitive reaction of aniline and Cu 2 O with APS.TEM images of PANI microspheres prepared using Cu 2 O as a template in the presence of H 3 PO 4 and APS as a dopant and an oxidant.