Paper strips coated with polypyrrole-wrapped carbon nanotube composites for chemi-resistive gas sensing

Low-cost, conductive Pap@CNT-NH2@PPy composites were prepared through sonochemical polymerization of pyrrole in the presence of oxidizing agent and tosylate co-dopant (TS) on cellulosic paper strips decorated with aminophenyl-modified multiwalled carbon nanotubes (CNT-NH2). The modified paper electrodes were examined by XPS, Raman, and SEM. The characterization of the electrochemical properties of the paper electrodes was conducted by cyclic voltammetry and electrochemical impedance spectroscopy. The Pap@CNT-NH2@PPy end materials served as chemiresistive NH3 sensors and exhibited an outstanding response of 525% to 0.1 ppm level of NH3 at RT with good stability for a long period of time. The LOD was found to be as low as 0.04 ppb. To sum up, this work demonstrates that combining aryl diazonium-modified carbon nanotubes and in situ sonochemical polymerization on paper surface permits to provide low cost, functional materials for gas sensors other paper electronic applications.