Nano-pH sensor for the study of reactive materials.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Accurate pH measurement is crucial in various scientific fields.
• Existing nano-pH sensors face challenges in stability and reproducibility.
• Understanding hydration processes in small reactive samples requires advanced sensing techniques.

Purpose of the Study:

• To develop and characterize a novel iridium oxide nano-pH sensor.
• To investigate the sensor's performance in a wide pH range (3-14).
• To demonstrate the sensor's application in studying the hydration of micro-sized reactive materials.

Main Methods:

• Fabrication of reproducible iridium nanotips with a 100 nm sensing area using a gallium focused ion beam.
• Coating nanotips with parylene for chemical insulation.
• Oxidation of iridium tips for stable pH response.
• Utilizing atomic force microscopy (AFM) for precise distance control.
• Calibration in buffer solutions to assess Nernstian behavior.

Main Results:

• Successful fabrication of a stable iridium oxide nano-pH sensor.
• Demonstrated Nernstian response with a slope of 59.2 mV/pH.
• Achieved precise sample positioning using AFM.
• Presented hydration results for micro-sized tricalcium silicate and tricalcium aluminate samples.

Conclusions:

• The developed nano-pH sensor offers a reliable tool for pH measurements in the 3-14 range.
• The sensor's stability and Nernstian behavior make it suitable for advanced applications.
• The study successfully demonstrated the sensor's capability in analyzing hydration of small reactive samples.