Microfluidic sensor for dynamic surface tension measurement.

Area of Science:

• Chemical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Interfacial tension is a critical parameter in multiphase systems.
• Existing methods for measuring interfacial tension often require large sample volumes and are time-consuming.
• Development of novel sensors for dynamic interfacial tension measurement is essential for various industrial applications.

Purpose of the Study:

• To report a novel microfluidic sensor for dynamic gas-liquid interfacial tension measurement.
• To demonstrate the sensor's ability to determine interfacial tension based on bubble formation frequency.
• To evaluate the sensor's potential for identifying critical micelle concentration (CMC) of surfactants.

Main Methods:

• Fabrication of a microfluidic chip with a microchannel network.
• Integration of an optical detection system for monitoring bubble formation.
• Controlled injection of sample and air at a fixed flow rate ratio.
• Calibration of the sensor using a commercial tensiometer for aqueous solutions of cetyl trimethyl ammonium bromide (CTAB).

Main Results:

• A clear relationship was established between surface tension and bubble formation frequency.
• The sensor successfully measured interfacial tension for varying concentrations of CTAB.
• The critical micelle concentration of CTAB was accurately identified using the developed sensor.

Conclusions:

• The microfluidic sensor provides a sensitive and efficient method for measuring dynamic gas-liquid interfacial tension.
• The sensor's ability to use minute sample volumes offers a significant advantage over conventional methods.
• This technology holds promise for applications requiring rapid and precise interfacial tension analysis.