Oxireductases in the Enzymatic Synthesis of Water-Soluble Conducting Polymers

Abstract

This chapter reviews recent advances in the field of biocatalytic synthesis of water-soluble conducting polymers. Biocatalysis is proposed as a versatile tool for synthesis of conducting polymers. First, the enzymatic synthesis of conducting polymers and its mechanism is discussed as well as the use of different type of enzymes. Next, we describe the use of a new bifunctional template (sodium dodecyl diphenyloxide disulfonate) in the synthesis of polyaniline as a strategy to improve the water solubility and electrical conductivity in the obtained polymer. The recent development of enzyme-catalyzed polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of polystyrenesulfonate is discussed. This method results in PEDOT materials that show an electrical conductivity of 2 × 10 −3 S cm −1 and posses excellent film formation ability, as confirmed by atomic force microscopy images. Finally, a simple method for immobilizing horseradish peroxidases in the biocatalytic synthesis of water-soluble conducting polymers is presented. This method is based on a biphasic catalytic system in which the enzyme is encapsulated inside the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, while other components remain in the aqueous phase. The enzyme is easily recovered after reaction and can be reused several times.

Insight into the template effect of vesicles on the laccase-catalyzed oligomerization of N-phenyl-1,4-phenylenediamine from Raman spectroscopy and cyclic voltammetry measurements

“…Similar effects of soft interfaces as “reaction regulators” (templates) of enzyme-catalyzed oxidative polymerizations have been known for several years 16 17 18 19 . They have been found with anionic micelles, as another type of molecular assemblies 13 18 20 21 22 , or with anionic polymers, such as sulfonated polystyrene (SPS) 18 23 24 25 26 27 28 29 . For all these previous examples, the regulating effect of the templates is still not completely understood.…”

Enzymatic Synthesis of Highly Electroactive Oligoanilines from a p-Aminodiphenylamine/Aniline Mixture with Anionic Vesicles as Templates

“…One of the most intensively investigated enzymatic polymerizations is that of aniline − to yield polyaniline (PANI) in its conductive, half-reduced, and protonated half-oxidized emeraldine salt form (PANI-ES), with delocalized unpaired electrons on every second nitrogen atom and fully aromatic benzene rings, the so-called polaron state. − The chemical structure of a constitutional repeating unit of PANI-ES with bipolarons, separated polarons, or polaron pairs is shown in Scheme . This is a highly idealized representation of the actual PANI-ES chains obtained.…”

“…Polymers or oligomers with characteristic features of polaronic PANI-ES units, with maximal absorption λ max at ≈1000 nm (assigned to the π → polaron transition) and ≈420 nm (polaron → π* transition) , can be obtained from aniline with oxidative enzymes and enzyme-specific oxidants, e.g., a peroxidase and H 2 O 2 or a laccase and O 2 . − Conceptually, there are two conditions that need to be fulfilled for a successful enzymatic polymerization of aniline into PANI-ES products. One is related to the property of the enzyme, the other is related to the property of the reaction medium.…”

Mechanistic aspects of the horseradish peroxidase-catalysed polymerisation of aniline in the presence of AOT vesicles as templates

“…oxidise) the monomers. 8 Therefore, the application of peroxidases [1][2][3][4][9][10][11][12] to obtain polymeric products with a desired and defined chemical structure is more challenging. One example is the peroxidase-catalysed polymerisation of aromatic monomers, such as the polymerisation of aniline with horseradish peroxidase (HRP) and H 2 O 2 as oxidant.…”