PVA cryogels obtained by biomimetic synthesis of polyaniline using hematin supported on halloysite nanotubes as catalyst

P. Jiménez-Cárdenas, J. Romero-García, A. Ledezma-Pérez, C. Alvarado-Canché, A. De León-Santillán, C. Gallardo-Vega
Centro de Investigación en Química Aplicada,

Keywords: poly(vinyl alcohol) cryogels, polyaniline, biomimetic polymerization, halloysite nanotubes, hematin


Polyaniline is one of the most interesting conductive polymers. In this work, we studied the biomimetic synthesis of polyaniline as an alternate route to prepare electrical conductive cryogels (ECC). For that purpose, hematin a natural porphyrin with peroxidase-like activity was supported in the lumen of natural geological halloysite nanotubes. The prepared materials were used as a biomimetic catalyst to polymerize aniline. Experiments using the biomimetic catalysts were carried out to probe the “in situ” and “ex situ” synthesis of polyaniline (PANi) in the presence of poly(vinyl alcohol) to further obtain cryogel structures. UV-vis, FTIR spectroscopies and swelling behavior were used to characterize ECC. Both the “in situ” and “ex situ” biomimetic synthesis of polyaniline allow the cryogel structure formation. The synthesized PANi corresponds to the emeraldine salt, the best result of swelling behavior was obtained when the PANi was synthesized “in situ”. These type of structures are unique in the sense that they combine the intrinsic electrical conductivity and the material properties of hydrogels. Besides, it is expected that such materials could be innocuous and free of any toxic contaminant, due to the synthesis method.