pH Sensitivity of Novel PANI/PVB/PS3 Composite Films

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Sensing

Background:

• Conductimetric sensing offers a promising alternative to conventional pH measurement methods.
• Polyaniline (PANI)/polyvinyl butyral (PVB)/polystyrene sulfonate (PS3) composite films were investigated for pH sensitivity.
• Screen-printing and drop-coating are deposition methods explored for film fabrication.

Purpose of the Study:

• To evaluate the pH sensitivity of novel PANI/PVB/PS3 composite films.
• To determine the optimal film deposition method for conductimetric pH sensing.
• To elucidate the sensing mechanism responsible for the observed pH response.

Main Methods:

• Fabrication of PANI/PVB/PS3 composite films using screen-printing and drop-coating.
• Conductimetric measurements to assess film response to varying pH levels.
• X-ray Photoelectron Spectroscopy (XPS) to analyze chemical changes in the film.
• Scanning Electron Microscopy (SEM) and Profilometry to evaluate film morphology.

Main Results:

• Screen-printed thick films exhibited the highest pH sensitivity, with conductance changing by three orders of magnitude over pH 2-11.
• The devices demonstrated stable performance over 96 hours of continuous operation.
• XPS analysis confirmed that changes in conductance were due to the deprotonation of the PANI polymer backbone.
• SEM and Profilometry indicated no significant changes in film morphology or dimensions upon exposure to buffer solutions.

Conclusions:

• PANI/PVB/PS3 composite films, particularly those prepared by screen-printing, are effective conductimetric pH sensors.
• The sensing mechanism relies on the deprotonation of the PANI backbone, leading to significant changes in film conductance.
• These films offer a stable and sensitive platform for pH monitoring with minimal structural alteration.