Sulfonated poly (ether ether ketone) based carbon dioxide gas sensor: Impact of sulfonation degree on sensing behavior at different humid condition

• Published in: Sensors and actuators. B, Chemical Vol. 303; p. 127115
• Main Authors: Bag, Souvik, Pal, Kaushik
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.01.2020; Elsevier Science Ltd
• Subjects: Bicarbonates; Carbon dioxide; Chemiresistive sensor; CO2 gas sensing; Detection; Diethanolamine; Electrical resistivity; Functionalized MWCNTs; Gas sensors; Humidity; Multi wall carbon nanotubes; Organic chemistry; Polymer composites; Polymer matrix composites; Relative humidity; Room temperature; Sensitivity; Sensitivity enhancement; Sensors; Polymer composites; Sensitivity; CO2 gas sensing; Chemiresistive sensor; Functionalized MWCNTs
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.127115

[Display omitted] •Polymer composite based Chemiresistive CO2 gas sensor.•Amine functionalization of MWCNTs (d-MWCNTs) improves gas sensing capability.•Sulfonation of PEEK matrix enhances CO2 sensitivity under relative humidity.•The composites based on SPEEK/d-MWCNTs with different degree of sulfonation.•High selectivity and repeatability towards CO2 gas. This work presents polymer composite based chemiresistive type carbon dioxide (CO2) gas sensors using different degree of sulfonated poly (ether ether ketone) (SPEEK) incorporated with diethanolamine (DEA)-functionalized multi-wall carbon nanotubes (d-MWCNTs) where incorporation of secondary amide functionalized MWCNTs improves the sensing capability by enhancing the electrical conductivity of the prepared composites. The sensors were fabricated using drop casting method on glass strips. The interaction mechanism mainly depends on the charge transportation between CO2 gas molecules and amide functionalized MWCNTs (d-MWCNTs). In addition, formation of bicarbonate ions (HCO3−) during interaction enhances the sensor sensitivity in different relative humidity. In sensing properties, SPEEK-5/d-MWCNTs (degree of sulfonation, i.e., DS = 71.03%) based sensor shows highest sensitivities (4.09 × 10-3 – 7.58 × 10-3 %  ppm−1) for the entire gas sensing measurement (500–5000 ppm) under different relative humidity (30–70% RH) at room temperature. The obtained results indicate that fabricated sensors are capable to detect CO2 gas in different humid conditions.