Participants/Project Abstracts
Summer 2007 Bioanalytical Science REU Participants
POLY(STYRENE-SULFONATE)-DOPED
POLY(ANILINE) NANOWIRE GAS SENSOR
Brian
Lunt, C. L. Aravinda, Syed Mubeen, and Ashok Mulchandani
Department
of Chemical & Environmental Engineering, University of California,
Riverside, CA 92521 and Arizona State University, Tempe, AZ 85287
Abstract
The
fabrication and application of a nanowire conducting polymer ammonia gas sensor
is demonstrated. Polyaniline
nanowires doped with polystyrene-sulfonate were grown potentiostatically and
electrochemically in alumina templates etched in phosphoric acid or sodium
hydroxide. The wires were placed
on wafers in a glass chamber through which ammonia gas was flowed at
concentrations between 0.1 and 10 ppm. Detection at various concentrations was measured in a chemiresistive
mode by measuring wire resistance change as a function of ammonia
concentration. The nanowires
produced by phosphoric acid etching demonstrated a decrease in resistance at
concentrations up to 0.5 ppm and an increase at greater concentrations, with
the sensor recovering slowly.The
sodium hydroxide template-etched wires showed a decrease in resistance at
concentrations up to 0.25 ppm with an increase at greater concentrations.This sensor did not recover as the
resistance did not return to its original value after pure argon was flowed
over the sensor for many hours. It
is concluded that polystyrene-sulfonate-doped polyaniline nanowires grown
template-assisted can be used as sensors capable of detecting ammonia at
concentrations as low as 0.1 ppm.
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