HCl Gas Sensor Coating Based on Poly(N-isopropylacrylamide) Nanoparticles Prepared from Water-Methanol Binary Solvent

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Poly(N-isopropylacrylamide) (PNIPAM) is a thermoresponsive polymer exhibiting a phase transition in aqueous solutions.
• Cononsolvency effects in binary solvent systems can alter polymer behavior and nanoparticle formation.
• Developing efficient methods for nanoparticle deposition on sensor surfaces is crucial for advanced sensing technologies.

Purpose of the Study:

• To investigate the formation and deposition of PNIPAM nanoparticles in a water-methanol binary solvent.
• To evaluate the performance of PNIPAM nanoparticle-coated sensors for HCl gas detection.
• To explore the influence of the cononsolvency effect on PNIPAM nanoparticle characteristics and sensor sensitivity.

Main Methods:

• Formation of PNIPAM nanoparticles in a water-methanol binary solvent at room temperature.
• Deposition of PNIPAM nanoparticles onto a resonator surface.
• Characterization of nanoparticle morphology using scanning electron microscopy.
• Measurement of sensor response and sensitivity to HCl gas.

Main Results:

• PNIPAM nanoparticles were successfully deposited on a resonator surface.
• Scanning electron microscopy revealed secondary nanoparticles composed of agglomerated primary particles (~10 nm diameter).
• The PNIPAM nanoparticle sensor exhibited enhanced response magnitude towards HCl gas compared to sensors from pure water.
• Sensitivity to 1 ppm HCl reached 3.3 Hz/ppm, with sensor recovery improving to nearly 100% by the third cycle.

Conclusions:

• The cononsolvency effect in water-methanol binary solvent facilitates the formation and deposition of PNIPAM nanoparticles for gas sensing.
• PNIPAM nanoparticle-based sensors demonstrate improved sensitivity and recovery for HCl gas detection.
• This approach offers a promising route for developing advanced chemical sensors.