Gas sensor and method of manufacture
Inventors
Aytug, Tolga • Fisher, Christine • Joshi, Pooran C. • Warmack, Robert J.
Assignees
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Publication Number
US-12461051-B2
Publication Date
2025-11-04
Expiration Date
Abstract
A low-cost and low-power polyaniline-based (PANI) gas sensor is provided. The PANI-based gas sensor is formed on a flexible polyimide (PI) substrate using additive manufacturing techniques. The gas sensor can include silver interdigitated electrode (IDE) arrays and conducting polymeric sensing films (i.e., PANI) that are printed onto the PI substrate using a direct-write technology of aerosol-jet printing. Aerosol-jet printing enables high-resolution, non-contact deposition of both the electrode and chemically sensitive materials. The gas sensor is optionally capable of 5 ppm sensitivity and a sub-ppm detection limit.
Core Innovation
The invention relates to a low-cost, low-power chemiresistive gas sensor using polyaniline (PANI) nanoparticle films. The gas sensor uses a flexible polyimide substrate and sensing film that bridges a gap between conductive electrodes, where resistance change relative to a baseline determines gas concentration.
A manufacturing approach is disclosed in which additive manufacturing via aerosol-jet direct-write deposits silver interdigitated electrodes and a PANI sensing film on a flexible polyimide substrate. The conductive electrodes are formed from a metal including at least one of silver, gold, platinum, and palladium, and the sensing film is aerosol-jet printed onto the polyimide substrate and over the electrodes so that the sensing film bridges the gap and includes the polyaniline nanoparticles.
The invention further discloses optional sensor structures intended to mitigate drift and enable reference behavior. Alternative multilayer stacked electrode geometry is described, including a mesh upper electrode and an optional laterally offset gas-impervious reference electrode formed for drift correction, and the sensing film can be doped with a polymeric acid dopant, including emeraldine-salt PANI nanoparticles.
Claims Coverage
The document includes five independent claims, covering both manufacturing of a polyaniline nanoparticle chemiresistive gas sensor and methods of detecting gas concentration by resistance comparison to a predetermined baseline. The main inventive features are the polyimide-based electrode-and-bridging sensing-film architecture, aerosol-jet direct-write fabrication of electrodes and sensing film, and optional stacked electrodes with a gas-impervious, laterally offset reference electrode.
Aerosol-jet printed polyimide chemiresistive sensing film bridging an electrode gap
Providing a polyimide substrate; aerosol-jet printing a pair of conductive electrodes on the polyimide substrate with interleaved fingers spaced apart by a gap, the electrodes being formed from a metal including at least one of silver, gold, platinum, and palladium; and aerosol-jet printing a mixture containing a plurality of polyaniline nanoparticles and a solvent onto at least a portion of the polyimide substrate and the pair of conductive electrodes to form a sensing film that overlies the pair of conductive electrodes and bridges a gap between the pair of conductive electrodes.
Polyimide-based gas sensor with polyaniline nanoparticle sensing film bridging a gap
A polyimide substrate having a pair of conductive metal electrodes formed thereon defining a gap, the electrodes being formed from silver, gold, platinum, or palladium; and a sensing film deposited onto at least a portion of the polyimide substrate and the pair of conductive metal electrodes such that the sensing film overlies the conductive metal electrodes and bridges the gap, wherein the sensing film includes a plurality of polyaniline nanoparticles.
Polyaniline nanoparticle sensing film doped with polymeric acid dopant bridging an electrode gap
A polyimide substrate having a pair of conductive electrodes formed thereon defining a gap; and a sensing film deposited onto at least a portion of the polyimide substrate and the pair of conductive electrodes such that the sensing film bridges the gap, wherein the sensing film includes a plurality of polyaniline nanoparticles, and wherein the sensing film is doped with a polymeric acid dopant.
Resistance measurement compared to a predetermined baseline to determine gas concentration
Providing a gas sensor including a polyimide substrate with a pair of conductive metal electrodes defining a gap and a sensing film deposited onto at least a portion of the polyimide substrate and the pair of conductive metal electrodes such that the sensing film bridges the gap, wherein the sensing film includes a plurality of polyaniline nanoparticles; measuring an electrical resistance of the gas sensor when the gas sensor is exposed to a gaseous environment containing a specified gas; and comparing the measured electrical resistance to a predetermined baseline electrical resistance to determine a concentration of the specified gas in the gaseous environment.
Stacked electrode gas sensor with aerosol-jet printed mesh upper electrode and interposed sensing film
Forming a lower electrode on a polyimide substrate from a metal including at least one of silver, gold, platinum, and palladium; aerosol-jet printing a mixture containing a plurality of polyaniline nanoparticles and a solvent onto an upper surface of the lower electrode to form a sensing film overlying at least a portion of the lower electrode; and aerosol-jet printing an upper electrode onto an upper surface of the sensing film, the upper electrode being formed from a metal including at least one of silver, gold, platinum, and palladium, and comprising a conductive mesh such that the sensing film is interposed between the lower electrode and the upper electrode.
Laterally offset gas-impervious reference electrode for a polyaniline nanoparticle sensing stack
Forming a lower electrode on a dielectric substrate; aerosol-jet printing a sensing film onto an upper surface of the lower electrode, the sensing film including a plurality of polyaniline nanoparticles; aerosol-jet printing an upper electrode onto an upper surface of the sensing film comprising a conductive mesh such that the sensing film is interposed between the lower electrode and the upper electrode; and forming a reference electrode onto the upper surface of the sensing film, the reference electrode being laterally offset from the upper electrode and impervious to a gas.
Across the independent claims, the central coverage is a polyimide-based chemiresistive gas sensor architecture where aerosol-jet printed polyaniline nanoparticle sensing film bridges an electrode gap, with gas concentration determined by comparing measured electrical resistance to a predetermined baseline. Additional claim coverage includes doping of the sensing film with a polymeric acid dopant and stacked electrode configurations that include a conductive mesh upper electrode and an optional laterally offset, gas-impervious reference electrode.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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