Effect of Additives on the in situ Laccase-Catalyzed Polymerization of Aniline Onto Bacterial Cellulose

Abstract

Laccase-mediated systems are a green route to accelerate the oxidation of aniline and obtain polyaniline with conductive properties. The synthesis of green polyaniline (emeraldine salt) was herein improved by the inclusion of additives like sodiumbis (2-ethyl hexyl) sulfosuccinate (AOT) and potassium hexacyanoferrate (II) (KHCF) in the medium. The aniline polymerization was confirmed by the detection of the absorption band typical of emeraldine salt at 420 nm, typical of the semiquinoid radical cation, and of the polaron absorption band at 700-800 nm, corresponding to the distinctive signal of doped or partial doped aniline. The oligomers and/or polymers obtained were characterized by spectrometry techniques, namely H-1 NMR and MALDI-TOF, and the bacterial cellulose (BC) conductivity was assessed by means of a four-point probe electrical conductivity technique. The best polymerization results were obtained with 5mM AOT, 10mM KHCF, and 25 U/mL of laccase. The synergistic effect between both additives in the presence of a catalyst leads to obtaining BC samples coated with green polyaniline with promising electric conductive properties.