The first use of electrospun nanofibrous membranes as highly responsive fluorescence quenching-based optical sensors for metal ions (Fe3+ and Hg2+) and 2,4-dinitrotoluene (DNT) is reported. A fluorescent polymer, poly(acrylic acid)−poly(pyrene methanol) (PAA−PM), was used as a sensing material. Optical chemical sensors were fabricated by electrospinning PAA−PM and thermally cross-linkable polyurethane latex mixture solutions. These sensors showed high sensitivities due to the high surface area-to-volume ratio of the nanofibrous membrane structures.

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.

SYNOPSISPolymers were synthesized from substituted phenolic and aromatic amine compounds with hydrogen peroxide as the source of an oxidizing agent and horseradish peroxidase enzyme as the catalyst. The polymerization reaction was carried out in a monophasic organic solvent with small amounts of water at room temperature. Conditions for the synthesis of polymers with respect to reaction time and yield were studied with a number of monomers at different concentrations and in solvents with different buffers with pH range of 5.0-7.5. Physical and chemical properties of these homo-and copolymers were determined with respect to melting point, solubility, elemental analysis, molecular weight distribution, infrared absorption (including FTIR) , solid-state 13C nuclear magnetic resonance, thermal gravimetric analysis, and differential scanning calorimetry. The enzyme catalyzed reactions produced polymers of molecular weight greater than 400,000 which were further fractionated by differential solubility in solvent mixtures and the molecular weight distribution of the polymer fractions were determined. In general, the polymers synthesized have low solubilities, high melting points, and some degree of branching.