A New Hybrid Sensitive PANI/SWCNT/Ferrocene-Based Layer for a Wearable CO Sensor

Abstract

Developing a sensing layer with high electroactive properties is an important aspect for proper functionality of a wearable sensor. The polymeric nanocomposite material obtained by a simple electropolymerization on gold interdigitated electrodes (IDEs) can be optimized to have suitable conductive properties to be used with direct current (DC) measurements. A new layer based on polyaniline:poly(4-styrenesulfonate) (PANI:PSS)/single-walled carbon nanotubes (SWCNT)/ferrocene (Fc) was electrosynthesized and deposed on interdigital transducers (IDT) and was characterized in detail using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoemission spectroscopy (XPS), and X-ray diffraction (XRD). The sensor characteristics of the material towards carbon monoxide (CO) in the concentration range of 10–300 ppm were examined, showing a minimal relative humidity interference of only 1% and an increase of sensitivity with the increase of CO concentration. Humidity interference could be controlled by the number of CV cycles when a compact layer was formed and the addition of Fc played an important role in the decrease of humidity. The results for CO detection can be substantially improved by optimizing the number of deposition cycles and enhancing the Fc concentration. The material was developed for selective detection of CO in real environmental conditions and shows good potential for use in a wearable sensor.

Resistive Chemosensors for the Detection of CO Based on Conducting Polymers and Carbon Nanocomposites: A Review

“…The added MWCNT increases the surface area of the reaction with the CO molecules; however, the complexity of the carbon structure hinders the sensitivity of the structure when exposed to low concentrations of the target gas, making such sensors usable only in high-concentration environments of 500–1000 ppm. The detection of low concentrations of CO (<300 ppm) was enabled by Savin et al by adding ferrocene (Fc) as a mediator to their PANI/SWCNT substrate [ 35 ]. Such structures have been observed to come with the additional benefit of limiting the effect of humidity on the sensor’s response.…”

Flexible, Stable and Self-Powered Two-Dimensional Layered Nanocomposites (PANI@MoS2) for Trace Ammonia Gas Detection

“…Four peaks in the N 1s spectra were identi ed at 399.2, 399.7, 401.3, and 402.3 eV, representing quinone imine (= N-), phenylamino (-NH-), protonated imine in the dipolaronic state (= NH + -), and protonated amine in the polaronic state (-NH 2 + -), respectively [44]. The proportion of quinone imine (= N-) at 399.2 eV for PANI-PSS was lower than that of PANI due to the spatial site-blocking effect of -SO 3 H group, which hindered the conversion of emeraldine to all-black aniline [45]. The ratio of the combined relative areas of N 1s characteristic peaks at 400.9 and 402.…”

Valorization of Agricultural Waste as a Chemiresistor H2S-Gas Sensor: A Composite of Biodegradable-Electroactive Polyurethane-Urea and Activated-Carbon Composite Derived from Coconut-Shell Waste

“…PANI is a biocompatible polymer with concentration (≥400 mg L −1 )-dependent toxicity [ 20 ]. PANI reinforced with various carbon fillers has been used to improve gas-sensing performance [ 21 , 22 , 23 , 24 , 25 , 26 ]. However, considering the poor solubility of PANI, aniline oligomer-based polymers have attracted intensive research interests in the past decade [ 27 ].…”