Low-Cost Optical pH Sensor with a Polyaniline (PANI)-Sensitive Layer Based on Commercial Off-the-Shelf (COTS)
Serguei Stoukatch1, Marc Debliquy2, Francois Dupont1
1Microsys Laboratory, Department of Electrical Engineering and Computer Science (Montefiore Institute), University of Liège, 4000 Liège, Belgium.
Micromachines
|December 23, 2023
Summary
We developed a low-cost, compact pH sensor using a polyaniline (PANI) thin film. This simple, functional device offers broad pH range sensitivity and requires minimal sample volume, making it ideal for various applications.
Area of Science:
- Materials Science
- Analytical Chemistry
- Sensor Technology
Background:
- Polyaniline (PANI) is a conductive polymer with potential for chemical sensing.
- Existing PANI-based pH sensors often rely on complex and expensive excitation or detection methods.
- There is a need for cost-effective, simple, and robust pH sensing solutions.
Purpose of the Study:
- To present a novel, low-cost, and compact prototype pH sensor.
- To demonstrate a simple and efficient PANI deposition technique.
- To validate the sensor's performance across a wide pH range.
Main Methods:
- Fabrication of a PANI thin film via a low-cost liquid-phase deposition process.
- Integration of a red-light-emitting diode (LED) and photodiode (PD) for optical detection.
- Development of integrated packaging using commercial off-the-shelf (COTS) components and surface mounting technology (SMT).
Main Results:
- The PANI layer exhibited excellent stability, solvent resistance, and compatibility.
- The sensor demonstrated sensitivity in the broad pH range of 3 to 9.
- The device requires a minimal sample volume of 55 µL and uses simple optical components.
Conclusions:
- A fully functional, low-cost pH sensor prototype was successfully developed.
- The sensor's design avoids sophisticated and expensive techniques, enhancing its practicality.
- The developed sensor is suitable for numerous applications requiring reliable pH monitoring.
