(521h) Au/Conducting Polymer Volatile Organic Compounds (VOC) Sensors Based on Oxidative Chemical Vapor Deposition (oCVD)

Au/conducting
polymer volatile
organic compounds (VOC) sensors based on oxidative chemical vapor deposition
(oCVD)

Xiaoxue Wang and Karen K. Gleason

Sponsorship: Shell company

Volatile
organic compounds (VOCs) are important hazards in petroleum industry. Hazardous
chemicals such as hydrocarbons and alcohols may lead
to explosions in refinery¹. However, current methods
to detect VOCs, such as metal oxide sensors and infrared chemical detectors,
require high fabrication temperature, high operation temperature, complicated
fabrication methods or high cost. Therefore, it is important for industry to
develop an economic and efficient way to detect VOCs. At the same time,
incorporating the chemical sensors into wireless sensor network is an emerging
trend². Here, we demonstrate a room temperature gold
nanoparticle-conducting polymer composite sensor for the application in
wireless sensor network. Conducting polymer poly(3,4-ethylenedioxythiohene-co-3-thipheneacetic
acid)
(poly(EDOT-co-TAA)) is deposited on printed circuit boards(figure 1 (a)) using
oxidative chemical vapor deposition(oCVD)³ technology. Wet chemistry⁴
was used to covalently tether gold nanoparticles via a linker molecule on the
copolymer film(figure 1(b)).  The hybrid film of gold nanoparticles and copolymer
film was characterized by scanning electron microscopy (SEM)(figure 1 (c)),
UV-vis, FTIR and XPS. The resistive response was defined as (R-R₀)/R₀
*100%.  We tested the response of these sensors to methanol (figure 1(d)),
water, acetone and toluene. The selectivity of methanol over acetone and
toluene is demonstrated. With simple fabrication method and low cost, our
sensors respond to VOCs with fast and high response. In
addition, fabricated under a mild temperature, our sensor is capable to be
directly deposited on printed circuit boards for a sensor network. The
operating temperature of our sensor is room temperature, which provides safe
and energy efficient detection of VOCs.

Figure 1 (a) the printed circuit board used in this sensor;
(b) the chemical structure of the conducting copolymer, and the gold
nanoparticle covalently linked on the polymer thin film; (c) SEM image for the
Au-polymer composite; (4) the resistive response to methanol vapors.

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