pH sensitivity of emeraldine salt polyaniline and poly(vinyl butyral) blend

Abstract

pH sensitivity of emeraldine salt polyaniline (ES-PANI) and poly(vinyl butyral) (PVB) blend film was investigated. This blend film can be used as a pH sensing element in new-type pH sensors to replace traditional instruments based on fragile glass electrodes for pH measurement of water in aquaculture farming. Structural and optical characteristic of PANI were studied by Fourier transform infrared spectroscopy (FTIR) and ultraviolet visible spectroscopy (UV-vis). Electrical characterization of ES-PANI:PVB blend films versus pH was performed with chemiresistors fabricated by micro-lithography. A ES-PANI:PVB layer was drop-coated on comb-shaped platinum electrodes patterned on SiO 2 /Si substrates. Scanning electron microscope (SEM) and optical microscope were used to investigate morphology of the fabricated platinum electrodes and the coated polymer blend films. I-V measurements of the polymer-coated chemiresistors were performed at very low relative humidity after the polymer films were exposed to pH 1-8. The results showed that logarithm of electrical resistance of the ES-PANI:PVB films increased almost linearly as pH increased from 1 to 8. The initial results showed that the PANI blend-coated chemiresistors can be used as pH sensors for water quality monitoring.

Polyaniline: Doping and Functionalization with Single Walled Carbon Nanotubes for Photovoltaic and Photocatalytic Application

“…Principally, we show the creation of a new absorption band at 387 nm, supporting the optical gap reduction. This broad band is the consequence of the transformation of PANI from leucomeraldine form to the emeraldine salt/base forms [43], which agrees well with FTIR results. Therefore, the newly created optical transition is the consequence of a new energetic level in the PANI band gap [44].…”

Optical pH sensor based on polyaniline sol-gel film immobilized with bromothymol blue and phenol red

“…As for PANI films as shown in FIGURE 3, two absorption bands at 323.4nm and 619nm has been also reported by [3].…”

“…The first commercial pH meters were invented around 1936 by Arnold Beckman consisting of glass electrode, reference cell and electrometer [1]. The pH meter will produce a small voltage and converted to pH units such as [2,3]. However, this electrochemical device have several problems including the need to have constant re-calibration [4] because it does not give a reproducible electromagnetic field over longer periods of times.…”

Single step modification of micrometer‐sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water

“…This may hinder the ion‐exchange reaction with chromate ions due to the competition with hydroxide ions for the same sorption sites on the composite particles . A variation in pH value is also known to have effect on the chemical structure of PANi . The structural variation with changing pH would eventually affect the ion‐exchange reaction .…”