Love Wave Sensors with Silver Modified Polypyrrole Nanoparticles for VOCs Monitoring

Abstract

Love wave sensors with silver-modified polypyrrole nanoparticles are developed in this work. These systems prove functional at room temperature with enhanced response, sensitivity and response time, as compared to other state-of-the-art surface acoustic wave (SAW) sensors, towards volatile organic compounds (VOCs). Results demonstrate the monitoring of hundreds of ppb of compounds such as acetone, ethanol and toluene with low estimated limits of detection (~3 ppb for acetone). These results are attributed to the use of silver-modified polypyrrole as a second guiding/sensitive layer in the Love wave sensor structure, which provides further chemically active sites for the gas-solid interactions. The sensing of low VOCs concentrations by micro sensing elements as those presented here could be beneficial in future systems for air quality control, food quality control or disease diagnosis via exhaled breath as the limits of detection obtained are within those required in these applications.

Nanostructured Metal Oxide-Based Acetone Gas Sensors: A Review

“…Furthermore, damage to eyes and nose are other effects of long-term exposure to acetone [6]. Accordingly, the occupational threshold limit value for acetone has been set to 250 ppm, considering an 8 h time weighted average [7]. Along with the negative effects to human body, it is a flammable substance with low explosive limit (LEL) of 2.6% and upper explosive limit (UEL) of 12.8% [8].…”

VOCs Sensing by Metal Oxides, Conductive Polymers, and Carbon-Based Materials

“…The reports related to POMs modification also point out improved functionality by their combination with other materials. In this line, a study of nanocomposites in which small amounts of Au [ 113 ] or Ag [ 107 ] were embedded into PPy showed improvement in the sensing properties of PPy to low ethylene and acetone concentrations, respectively. A similar approach also indicated potential advantages on acetone detection for PPy modified with CdTe quantum dots [ 108 ] and polytetrafluoroethylene (PTFE) modified with Ti [ 109 ].…”

Equivalent Circuit Model Extraction for a SAW Resonator: Below and above Room Temperature

“…Such variations can be measured with high-accuracy frequency estimation algorithms [ 17 ] and easily related to the physical quantity of interest [ 18 ]. SAW resonators have been successfully employed for temperature and humidity sensing [ 15 , 19 , 20 , 21 ], as pressure sensors [ 16 , 22 , 23 ], biosensors [ 24 ], and for VOC and gas sensing [ 25 , 26 , 27 , 28 ]. They have also been employed in harsh environments [ 14 , 29 , 30 ].…”