Biocatalytic synthesis of polypyrrole powder, colloids, and films using horseradish peroxidase.
Polypyrrole was synthesized in high yield by a biocatalytic method in mild aqueous media using hydrogen peroxide as oxidizer. A redox mediator, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) diammonium salt, was used to oxidize the pyrrole. ABTS is a very effective peroxidase substrate, which was enzymatically oxidized to generate a radical cation that in turn was able to chemically oxidize pyrrole. This indirect biocatalytic method was implemented because pyrrole is not a substrate of horseradish peroxidase, however, the polymerization process was successfully optimized and later adapted to prepare also polypyrrole thin films and water dispersible polypyrrole colloids. The polypyrrole powder and colloids were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, electrical conductivity, and thermogravimetric analysis. In addition, the deposition of the polypyrrole thin film was monitored using a quartz-crystal microbalance and its morphology studied by optical and scanning electron microscopy. The biocatalytic polymerization of pyrrole results in a polymer spectroscopically very similar to chemically synthesized polypyrrole.
Centro de Investigación en Ingeniería y Ciencias Aplicadas, UAEM, Av. Universidad 1001, Col. Chamilpa, CP 62210 Cuernavaca, Morelos, Mexico. rcruzsilva@uaem.mx
R
R
Cruz-Silva
E
E
Amaro
A
A
Escamilla
M E
ME
Nicho
S
S
Sepulveda-Guzman
L
L
Arizmendi
J
J
Romero-Garcia
F F
FF
Castillon-Barraza
M H
MH
Farias
D055162:Biocatalysis; D003102:Colloids / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D011208:Powders; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties
D003102:Colloids; D011108:Polymers; D011208:Powders; D011758:Pyrroles; C067635:polypyrrole; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase