The Role of Template in the Enzymatic Synthesis of Conducting Polyaniline

Abstract

It was recently reported that water soluble conducting polyaniline may be prepared using a new template-guided enzymatic approach. To address the mechanistic role of the template in this reaction, various macromolecular and surfactant templates were investigated. It was found that the template provides a necessary type of “local” environment where the pH and charge density near the template molecule is different from that of the bulk solution. 13C and 1H NMR studies showed that this “local” environment serves as a type of nano-reactor that is critical in anchoring, aligning, and reacting the aniline monomers and ultimately controls what form of polyaniline (conducting or insulating) is obtained during reaction. Strong acid polyelectrolytes, such as sulfonated polystyrene (SPS), are the most favorable because they provide a lower, local pH environment that serves to both charge and preferentially align the aniline monomers through electrostatic and hydrophobic interactions to promote the desired head-to-tail coupling. Interestingly, it was found that micelles formed from aggregating, strong acid surfactant molecules such as sodium dodecylbenzenesulfonic acid (SDBS) also provide suitable local template environments that lead to the formation of conducting polyaniline. 1H NMR spectral data showed that the aniline monomers in these micelle systems intercalate between the sulfonated styrene headgroups of the micelles. However, if the reaction media was such that micelles were not formed or if the distance between the sulfonated headgroups in the mixed micelle systems was too large, then the conducting form of polyaniline could not be obtained. The information gained from this study strongly supports the existence and importance of “local” template environments in guiding the enzymatic synthesis of polyaniline. A fundamental understanding of these types of mechanisms should lead to the design and optimization of a broad range of other interesting template-guided reactions.

Bacteriophage M13 as a scaffold for preparing conductive polymeric composite fibers

“…570 nm suggests that, at pH 10, PANi has been completely de-doped to the base form. These results are comparable to those previously observed for both chemically and enzymatically synthesized PANi [27,28,30,37].…”

“…The conductivity is similar to literature reports where PSS was used as the doping agent [27,28]. The PSS-PANi/m-M13 composite fibers could be easily fabricated into thin fi lms via a spincoating process (Fig.…”

“…3(a), upon modifi cation, m-M13 239 Nano Res (2008) 1: 235 241 Composite fiber conductivity was determined to be 5×10 4 S/cm using a standard four-point probe technique. The conductivity is similar to literature reports where PSS was used as the doping agent [27,28]. The PSS-PANi/m-M13 composite fibers could be easily fabricated into thin fi lms via a spincoating process (Fig.…”

“…solution and was found to be crucial for the success of the synthesis [36]. In addition, PSS served as an acidic dopant to enhance the conductivity of PANi [27,28]. As shown in Fig.…”

Enzymatic synthesis of water‐soluble conducting poly(3,4‐ethylenedioxythiophene): A simple enzyme immobilization strategy for recycling and reusing

“…7 The use of enzymes as biocatalysts for the synthesis of conducting polymers has been studied in last years as a ''green synthesis process'' alternative. [8][9][10][11] Enzymes can offer environmentally benign reaction conditions, 2,12 a high yield of polymerization, and higher control in regioregularity and stereochemistry, 8,13 consequently resulting in soluble and processable conducting polymers.…”