Wireless Oxygen Sensors Enabled by Fe(II)-Polymer Wrapped Carbon Nanotubes

Abstract

Oxygen causes food spoilage and drug degradation, which is addressed commercially by modified atmosphere packaging. We report herein a wireless oxygen sensor, O-p-CARD, from solution processed Fe-poly(4-vinylpyridine)-single-walled carbon nanotube composites on commercial passive near-field communication tags. A large irreversible attenuation in the reflection signal of an O-p-CARD was observed in response to oxygen at relevant concentrations, enabling non-line-of-sight monitoring of modified atmosphere packaging. These devices allow for cumulative oxygen exposure inside a package to be read with a conventional smartphone. We have demonstrated that an O-p-CARD can detect air ingress into a nitrogen-filled vegetable package at ambient conditions. This technology provides an inexpensive, heavy-metal-free, and smartphone-readable method for in situ non-line-of-sight quality monitoring of oxygen-sensitive packaged products.

Sensor Technologies Empowered by Materials and Molecular Innovations

“…[35] When the signals are sufficiently large,SWCNT sensor compositions can be used to create smartphone-compatible RFID sensors. [36] Concluding Remarks and Outlook An important trend in evaluating sensory materials is to move beyond the laboratory and test in real-world conditions with confounding chemical signals.L aboratory testing is still critical, and the controlled exposure of sensors to variances in temperature and humidity,f or example,a re needed to evaluate any technology.E xposing sensors to am ultiplicity of chemical vapors also characterizes the scope of the molecular recognition. Sometimes the real world is simpler than the laboratory stress tests to which we subject our sensors.F or example,i fy ou are seeking to detect biogenic amines coming from meat spoilage or ethylene associated with fruit ripening,y ou should not have to worry about competition with typical organic solvents.I ti si mportant to note that chemical sensors will always suffer from limited selectivity as all sensing materials,w ith the exception of DNA, display cross-reactivity.T his realization gave birth to the ideas of artificial olfaction and the use of multiple sensors to create unique composite signatures for particular odors.…”

“…As shown in Figure , arrays can be easily printed on flexible substrates and these materials can be used to detect alkenes for the monitoring of produce ripening, or biogenic amines for monitoring the quality of meat . When the signals are sufficiently large, SWCNT sensor compositions can be used to create smartphone‐compatible RFID sensors …”

Sensortechnologien durch neuartige Materialien und Moleküle

“…Wie in Abbildung gezeigt ist, können diese Matrizen leicht auf flexible Substrate gedruckt werden, und diese Sensoren können beispielsweise zum Nachweis von Alkenen zur Beobachtung der Reifung von Früchten oder von biogenen Aminen zur Überprüfung des Verderbens von Fleisch verwendet werden . Wenn die Signale ausreichend groß sind, können SWCNT‐Sensoren dazu verwendet werden, Smartphone‐kompatible RFID‐Sensoren zu erzeugen …”

Chemiresistors for the Real‐Time Wireless Detection of Anions

“…In our previous studies, mechanically a robust sensing platform was successfully developed by noncovalently wrapping of single‐walled CNTs (SWCNTs) with poly(4‐vinylpyridine) (P4VP) and then covalently anchoring this complex to a glass substrate . The pyridyl groups from P4VP afford additional post‐functionalization of the immobilized SWCNT assemblies with analyte‐specific selectors.…”