Low-Cost Polyethylene Terephthalate Fluidic Sensor for Ultrahigh Accuracy Measurement of Liquid Concentration...

Area of Science:

• Materials Science
• Analytical Chemistry
• Optical Sensing

Background:

• Accurate measurement of fluidic solution concentration is crucial in various scientific and industrial applications.
• Existing sensors may be costly or lack the required sensitivity for certain detection tasks.
• Development of cost-effective and high-performance fluidic sensors remains an active area of research.

Purpose of the Study:

• To demonstrate a low-cost polyethylene terephthalate fluidic sensor (PET-FS) for measuring concentration variations in fluidic solutions.
• To evaluate the sensitivity and resolution of the developed PET-FS.
• To establish the linearity of the sensor's response to concentration changes.

Main Methods:

• Fabrication of a PET-FS comprising a triangular fluidic container with an attached birefringent PET thin layer.
• Integration of the PET-FS into a common path polarization interferometer utilizing a heterodyne scheme.
• Measurement of probe light phase variation to correlate with fluidic liquid concentration changes.

Main Results:

• The PET-FS achieved a sensitivity of 3.52 × 10^4 deg./RIU and a resolution of 6.25 × 10^-6 RIU for sodium chloride solutions.
• For hydrochloric acid solutions, the sensor exhibited a sensitivity of 5.62 × 10^4 deg./RIU and a resolution of 6.94 × 10^-6 RIU.
• A linear relationship (R-squared > 0.995) was observed between the measured phase variation and the concentration of the fluidic solutions.

Conclusions:

• The developed low-cost PET-FS is effective for accurate concentration measurement of fluidic solutions.
• The sensor demonstrates high sensitivity and resolution, comparable to more expensive alternatives.
• The linear response and robust performance indicate the PET-FS's potential for practical applications in chemical sensing.