Enzymatically Synthesized Conducting Polyaniline

Abstract

A novel strategy for the enzymatic synthesis of a water-soluble, conducting polyaniline (PANI)/sulfonated polystyrene (SPS) complex is presented. The enzyme horseradish peroxidase (HRP) is used to polymerize aniline in the presence of a polyanionic template, sulfonated polystyrene. The synthesis is simple, and the conditions are mild in that the polymerization may be carried out in a 4.3 pH buffered aqueous solution, with a stoichiometric amount of hydrogen peroxide and a catalytic amount of enzyme. UV−visible absorption, FTIR, GPC, elemental analysis, and conductivity measurements all confirm that the electroactive form of PANI, similar to that which is traditionally chemically synthesized, is formed and complexed to the SPS. The reversible redox activity of the polyaniline displays a unique hysteresis loop with pH change. Cyclic voltammetry studies show only one set of redox peaks over the potential range of −0.2 to 1.2V, which suggests that the PANI/SPS complex is oxidatively more stable. The conductivity of the complex is found to increase with the molar ratio of PANI to SPS. Conductivities of 0.005 S/cm are obtained with the pure complex and may be increased to 0.15 S/cm after additional doping by exposure to HCl vapor. This enzymatic approach offers unsurpassed ease of synthesis, processability, stability (electrical and chemical), and environmental compatibility.

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].…”

“…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.…”

“…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].To study the electrical conductivity, the composite fibers were coated on a glass wafer ( =10 Ω·cm) by casting 200 μL of a 0.2 mg/mL composite fiber solution and drying overnight at room temperature. solution and was found to be crucial for the success of the synthesis [36].…”

“…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.…”

Manipulating DNA Conformation Using Intertwined Conducting Polymer Chains

“…The pK a of the benzenesulfonic group in SPS is much lower than that of the phosphate group in DNA. 21 Therefore, at pH 4, the DNA is less dissociated when compared with the SPS, therefore affecting the degree and reversibility of the doping/dedoping process. It is important to note however that observance of this doping/dedoping process further supports both the presence and electroactivity of polyaniline with the DNA template.…”