MULTIPLE NON-CONDUCTIVE POLYMER SUBSTRATES AND CONDUCTIVE COATINGS AND METHODS FOR DETECTING VOC
A product for sensing may include a non-conductive layer of a polymer that may be selected for its responsiveness to a stimulus from one of a selected analyte, or a selected group of analytes. The non-conductive layer may be non-conductive of an electrical current. A conductive layer may be in contact with the non-conductive layer and may be conductive of the electrical current. A lead for may provide an electric current to the conductive layer. A device may be provided to detect at least one property of the conductive layer in response to the stimulus.
This application claims benefit of U.S. Provisional Application No. 62/186,568 filed Jun. 30, 2015.
TECHNICAL FIELDThe field to which the disclosure generally relates to includes sensor devices and methods of detecting compositions, in particular, volatile organic compounds.
BACKGROUNDIn a number of variations, sensor devices may be used to measure environmental conditions or variables pertaining to components.
SUMMARY OF ILLUSTRATIVE VARIATIONSA number of illustrative variations may involve a product for sensing that may include a non-conductive layer of a polymer that may be selected for its responsiveness to a stimulus from one of a selected analyte, or a selected group of analytes. The non-conductive layer may be non-conductive of an electrical current. A conductive layer may be in contact with the non-conductive layer and may be conductive of the electrical current. A lead may provide an electric current to the conductive layer. A device may be provided to detect at least one property of the conductive layer in response to the stimulus.
Additional illustrative variations may involve a method of monitoring for an exposure to an analyte. A sensing device may be provided with a non-conductive layer. A lead structure may be provided to apply a current to a zone of the sensing device that exhibits an opposition to the current. The opposition may vary in response to the exposure of the non-conducting layer to the analyte.
Other illustrative variations within the scope of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing variations within the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Select examples of variations within the scope of the invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the invention, its application, or uses.
The variable may involve a status of a device or environment such as state of charge, or state of health, depletion status, diagnosis properties, or other variables indicative of status. In a number of variations, a plurality of sensor devices 14 may be used to monitor the surface or space where sensing is desired, as further described below. The sensor device 14 may include at least one lead 22, which may be in contact with the conductive layer 18 to monitor at least one variable such as resistance or impedance. Resistance and impedance may be generally referred to an opposition to the passage of an applied current from a DC or AC source, respectively, through an area of interest. In a number of variations, the sensor device 14 may include a data acquisition module (DAQ) 24. With additional reference to
In a number of variations, the non-conductive layer 16 may include a polymeric material. The non-conductive layer 16 may comprise a polymer including, but not limited to, Acrylonitrile butadiene styrene (ABS), Polymethyl Methacrylate (PMMA), Celluloid, Cellulose acetate, Cycloolef in Copolymer (COC), Ethylene-Vinyl Acetate (EVA), Ethylene vinyl alcohol (EVOH), Fluoroplastics (including PTFE, FEP, PFA, CTFE, ECTFE, ETFE)lonomers, Kydex™, a trademarked acrylic/PVC alloy, Liquid Crystal Polymer (LCP), Polyacetal (POM or Acetal), Polyacrylates (Acrylic), Polyacrylonitrile (PAN or Acrylonitrile), Polyamide (PA or Nylon), Polyamide-imide (PAI), Polyaryletherketone (PAEK or Ketone), Polybutadiene (PBD), Polybutylene (PB), Polybutylene terephthalate (PBT), Polycaprolactone (PCL), Polychlorotrifluoroethylene (PCTFE), Polyethylene terephthalate (PET), Polycyclohexylene dimethylene terephthalate (PCT), Polycarbonate (PC), Polyhydroxyalkanoates (PHAs), Polyketone (PK), Polyester, Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherimide (PEI), Polyethersulfone (PES), Polysulfone, Polyethylenechlorinates (PEC), Polyimide (PI), Polylactic acid (PLA), Polymethylpentene (PMP), Polyphenylene oxide (PPO), Polyphenylene sulfide (PPS), Polyphthalamide (PPA), Polystyrene (PS), Polysulfone (PSU), Polytrimethylene terephthalate (PTT), Polyurethane (PU), Polyvinyl acetate (PVA), Polyvinyl chloride (PVC), Polyvinylidene chloride (PVDC), Styrene-acrylonitrile (SAN), polycarbonate+acrylonitrile butadiene styrene mix (ABS+PC), Polypropylene (PP) (including, but not limited to, impact, random, and homo), Polyethylene (PE) (including, but not limited to, linear low density, linear high density), combinations or blends in any amount thereof, or may be another type. In a number of variations, the non-conductive layer 16 may be a combination of the above polymers in any amount or concentration. In a number of variations, the non-conductive layer 16 may include a composite layer comprising several layers of the materials listed. In a number of variations, the non-conductive layer 16 may be formed via a method including, but not limited to, injection moulding, extrusion moulding, structural foam, vacuum forming, extrusion blow moulding, a hand lay-up operation, a spray lay-up operation, a pultrusion operation, a chopped strand mat, vacuum bag moulding, pressure bag moulding, autoclave moulding, resin transfer moulding, vacuum assisted resin transfer moulding, bladder moulding, compression moulding, mandrel wrapping, wet layup, chopper gun, filament winding, melting, staple fiber, continuous filament, or may be formed another way.
In a number of variations, the conductive layer 18 may include a metallic or semimetallic material. In a number of variations, the conductive layer 18 may include a metal including, but not limited to, plastic steel, stainless steel, copper, nickel, tin, gold, silver, molybdenum, palladium, tungsten, graphite or another form of carbon, zinc, iron, bronze, aluminum, titanium, platinum, silicide, or may be another type), metallic alloys, combinations thereof, or may be another type. In a number of variations the conductive layer may include a non-metal material that conducts electric current sufficiently to measure changes in impedance or resistance. In a number of variations, the conductive layer 18 may be a combination of the materials in any amount or concentration. In a number of variations, the conductive layer 18 may include a composite layer comprising several layers of the materials. In a number of variations, the conductive layer 18 may be formed on or overlying the non-conductive layer 16 via a method including, but not limited to, inkjet/laser printing, 3-D printing, casting, extrusion, forging, plating (electroless, electro), plasma spraying, aerosol spraying, thermal spraying, dip coating, roll-to-roll coating, spin coating, spray coating, chemical solution deposition, thermal evaporation, pulsed laser deposition, cathodic arc deposition, or known etching techniques (i.e. sputter, Chemical Vapor Deposition, Physical Vapor Disposition, Atomic Vapor Disposition, ALD, or combination of deposition and thermal growth), conversion coating, ion beam mixing, thin film printing, or may be formed another way. The process for applying the conductive layer 18 may be selected to enhance permeability of a monitored compound to the non-conductive layer 16, such with a vapor deposition process. In a number of variations, the at least one lead 22 may include a conductor such as a metal material, and may be used to measure resistance or impedance in an area of interest. In a number of variations, the at least one lead 22 may include a metal including, but not limited to, plastic steel, stainless steel, copper, nickel, tin, gold, silver, molybdenum, palladium, tungsten, graphite or another form of carbon, zinc, iron, bronze, aluminum, titanium, platinum, silicide, or may be another type), metallic alloys, combinations thereof, or may be another type. In a number of variations, the at least one lead 22 may be a combination of materials in any amount or concentration. In a number of variations, the at least one lead 22 may include a composite layer comprising several layers of materials. In a number of variations, the at least one lead 22 may be formed on or overlying the conductive layer 18, or otherwise in contact therewith (such as being formed on the non-conductive layer 16), via a method including, but not limited to, inkjet/laser printing, 3-D printing, casting, extrusion, forging, plating (electroless, electro), plasma spraying, thermal spraying, dip coating, roll-to-roll coating, spin coating, spray coating, chemical solution deposition, thermal evaporation, pulsed laser deposition, cathodic arc deposition, or known etching techniques (i.e. sputter, Chemical Vapor Deposition, Physical Vapor Disposition, Atomic Vapor Disposition, ALD, or combination of deposition and thermal growth), conversion coating, ion beam mixing, thin film printing, or may be formed another way. In a number of variations, the at least one lead 22 may be attached to the conductive layer 18, (or the non-conductive layer 16 with electric coupling to the conductive layer 18 so as to have minimal resistance there between), through an adhesive comprising at least one of, silver paste, acrylonitrile, cyanoacrylate, acrylic, resorcinol glue, epoxy resin, epoxy putty, ethylene-vinyl acetate, phenol formaldehyde resin, polyamide, polyester, polyethylene, polypropylene, polysulfides, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinyl chloride emulsion, polyvinylpyrrolidone, rubber cement, silicone, combinations thereof, or may be another type. In the case of attachment of the lead(s) 22 to the conductive layer 18, the adhesive may be selected to be electrically conductive to make good ohmic contact. In a number of variations as shown in
In a number of variations, the sensor device 14, non-conductive layer 16, and/or conductive layer 18 may operate as a strain gauge. In a number of variations, the sensor device 14, non-conductive layer 16, and/or conductive layer 18 may be used to operate as a strain gauge to measure a variable by measuring deformation of the substrate to which the sensor device 14 may be mounted, and/or of the non-conductive layer 16, or change in resistance of the conductive layer 18 through at least one calculation. In a number of variations, the use of multiple leads 22 may be used to pinpoint a location of deformation, wherein different changes may be detected through different leads at known locations. In a number of variations, the sensor device 14, non-conductive layer 16, and/or conductive layer 18 may be used to operate as a strain gauge to measure compounds such as volatile organic compounds (VOC's) in vapor state by measuring deformation of the substrate to which the sensor device may be mounted and/or non-conductive layer 16, or change in resistance/reactance of the conductive layer 18. In a number of variations, the VOC's may include, but are not limited to, aromatic and aliphatic hydrocarbons, ketones, imides, amides, mercaptans or aldehydes, or maybe another compound. The sensor device 14 provides the ability to detect VOCs in low concentrations through deformation induced by VOC ab(d)sorption in an electrically insulating polymer —non-conducting layer 16. The deformation may be detected by measuring changes in resistance or impedance of the conductive coating and/or of the non-conducting layer 16. Direct current may be used, and alternating current is an alternative. The polymer non-conducting layer 16 may absorb/adsorb the organic gas phase compounds causing micro swelling and elastic deformation. The resulting strain may modify the conduction paths of the conductive layer 18 resulting in a measurable resistance or impedance change.
An ability to discriminate to analytes of choice, in the sensor device 14 with a rapid response, reversibility and high sensitivity may be provided, along with an ability to operate in environments with humidity/water. The non-conductive layer 16 may advantageously desorb water that has been absorbed, reversibly. In a number of variations fluorinated polymers that may be highly hydrophobic may be used for the non-conductive layer 16, or portions thereof, as a way of differentiating between high humidity and high VOC levels. Use of a fluorinated polymer may inhibit absorption of water. For example, the non-conductive layer 16 may be composed of PVDF, PTFE, PCTFE, FEP, ETFE, ECTFE, or another polymer with hydrophobic properties. This is advantageous since it increases the already existing ability of sensors device 14 to perform without a need to be shielded from water. In a monitoring application, multiple sensor devices 14 may be used, one of which may include a fluorinated polymer as the non-conductive layer 16. If the nonfluorinated sensor devices 14 are triggered it may be due to VOC or humidity. If the fluorinated sensor device 14 is not triggered while the nonfluorinated ones are, the cause may be concluded to be a rise in humidity. If both the fluorinated and nonfluorinated sensor devices 14 are triggered the cause can be concluded to be a rise in VOC concentration. In a number of other variations, the materials for the non-conductive layer 16 of the sensor devices 14 may be selected so that their VOC response is comparable but their response to humidity is measurably different.
In a number of variations as illustrated in cross section in
With reference again to
Also, in a number of variations, the data acquisition module (DAQ) 24, or electronic control module (ECM) 25, may be configured to provide storage for data received by or loaded to the at least one of the other of the data acquisition module (DAQ) 24 or electronic control module (ECM) 25, or to the at least one sensor device 14, or to a different component of a vehicle, or the like, for processor-executable instructions or calculations. The data, calculations, and/or instructions may be stored, for example, as look-up tables, formulas, algorithms, maps, models, and/or any other suitable format. The memory may include, for example, RAM, ROM, EPROM, and/or any other suitable type of storage article and/or device.
In a number of variations, the interfaces may include, for example, analog/digital or digital/analog converters, signal conditioners, amplifiers, filters, other electronic devices or software modules, and/or any other suitable interfaces. The interfaces may conform to, for example, RS-232, parallel, small computer system interface, universal serial bus, CAN, MOST, LIN, FlexRay, and/or any other suitable protocol(s). The interfaces may include circuits, software, firmware, or any other device to assist or enable the data acquisition module (DAQ) 24 or electronic control module (ECM) 25, in communicating with other devices.
In a number of variations as illustrated in
In a number of variations a semi-permeable layer 19 such as PVC or low density PE (shown in
In a number of variations an array of sensors may be used. For example, the array may include a sensor device 54 with selected different nonconductive polymers provided in the quadrants of the nonconductive layer 16. For example, as shown in
With reference to
With reference to
In a number of variations, the methods or parts thereof may be implemented in a computer program product including instructions or calculations carried on a computer readable medium for use by one or more processors to implement one or more of the method steps or instructions. The computer program product may include one or more software programs comprised of program instructions in source code, object code, executable code or other formats; one or more firmware programs; or hardware description language (HDL) files; and any program related data. The data may include data structures, look-up tables, or data in any other suitable format. The program instructions may include program modules, routines, programs, objects, components, and/or the like. The computer program may be executed on one processor or on multiple processors in communication with one another.
In a number of variations, the program(s) can be embodied on computer readable media, which can include one or more storage devices, articles of manufacture, or the like. Illustrative computer readable media include computer system memory, e.g. RAM (random access memory), ROM (read only memory); semiconductor memory, e.g. EPROM (erasable, programmable ROM), EEPROM (electrically erasable, programmable ROM), flash memory; magnetic or optical disks or tapes; and/or the like. The computer readable medium also may include computer to computer connections, for example, when data may be transferred or provided over a network or another communications connection (either wired, wireless, or a combination thereof). Any combination(s) of the above examples is also included within the scope of the computer-readable media. It is therefore to be understood that the method may be at least partially performed by any electronic articles and/or devices capable of executing instructions corresponding to one or more steps of the disclosed methods.
In a number of variations, as shown in
In a number of variations as illustrated with the assistance of
Referring again to
As detailed above, the sensor device 14 may have multiple advantages including superior long term stability of the sensor element since the polymer's chemical reactivity to the ambient environment is decoupled from the transduction mechanism through inclusion of the conductive layer 18, a faster response, and a higher degree of reversibility since the transduced signal does not rely on a chemical interaction between the polymer and analyte. Use of the non-conducting layer 16 supports performance without a need to be shielded the sensor device 14 from water and oxygen since the polymer will not degrade over time with exposure to them. The sensor device 14 may be used for analyte detection, identification, classification, and/or tracking through a polymer non-conducting layer 16 with conductive layer 18 that may be provided as a coating on the non-conducting layer 16. Electrical resistance or impedance changes may be used for analyte detection and classification. Signal processing for the detection, identification, classification and/or tracking of a narrow band of likely analyte. Tuning sensitivity for a specific analyte may be accomplished by altering the composition of the non-conductive layer 16. For example, PMMA may be used due to its sensitivity to polar compounds while PE or PP may be used due to their sensitivity to nonpolar species. An array of sensors with unique response to individual analyte may be used for classifications. Examples of uses of the products and methods described herein may include food quality inspection, pharmaceutical processing, chemical synthesis, beverage processing, monitoring for health purposes, cosmetic production, manufacturing plant monitoring, vehicle interior air quality, residential air evaluation, vehicle shed testing, or any application where the monitoring, detection, identification, classification, and/or tracking of analytes is desired. Specific uses may involve employing an array of multiple detectors with differing polymer composition as the non-conductive layer to discriminate between emissions from adhesives or polymer components in a vehicle or a fuel or oil source during a vehicle sealed housing evaporative determination (SHED), test. Another use may involve diagnosis of welding tips by evaluating the gases resulting from a welding process where a depleted weld tip releases different VOCs than a non-depleted weld tip.
The following description of variants is only illustrative of components, elements, acts, product and methods considered to be within the scope of the invention and are not in any way intended to limit such scope by what is specifically disclosed or not expressly set forth. The components, elements, acts, product and methods as described herein may be combined and rearranged other than as expressly described herein and still are considered to be within the scope of the invention.
Variation 1 may involve a product for sensing that may include a non-conductive layer of a polymer that may be selected for its responsiveness to a stimulus from one of a selected analyte or a selected group of analytes. The non-conductive layer may be non-conductive of an electrical current. A conductive layer may be in contact with the non-conductive layer and may be conductive of the electrical current. A lead may provide an electric current to the conductive layer. A device may be provided to detect at least one property of the conductive layer in response to the stimulus.
Variation 2 may include the product according to variation 1 wherein the conductive layer may be in contact with a surface of the non-conductive layer and may cover only a portion of the surface so that an area of the surface may be exposed directly to the stimulus.
Variation 3 may include the product according to variation 1 wherein the non-conductive layer may be comprised of areas of different polymers having different responses to the stimulus.
Variation 4 may include the product according to variation 3 wherein the areas may be part of one contiguous structure.
Variation 5 may include the product according to variation 1 wherein the lead may include at least a first pair of leads and a second pair of leads. The first pair of leads may be spaced from each other at a first distance. The second pair of leads may be spaced from each other at a second distance that may be greater than the first so that the first and second pairs of leads communicate a different response to the stimulus.
Variation 6 may include the product according to variation 1 wherein the device may include a data acquisition module that may be in communication with the lead to collect information on responses to the stimulus.
Variation 7 may include the product according to variation 1 wherein the lead may be applied to the conductive layer.
Variation 8 may include the product according to variation 1 wherein the lead may be disposed between the conductive layer and the non-conductive layer.
Variation 9 may include the product according to variation 1 wherein the lead may be a number of spaced apart leads.
Variation 10 may include the product according to variation 1 and may include a semi-permeable layer overlying one of the non-conductive layer or the conductive layer. The semi-permeable layer may have a pore size selected to pass the selected analyte or the selected group of analytes.
Variation 11 may involve a method of monitoring for an exposure to an analyte. A sensing device may be provided with a non-conductive layer. A lead structure may be provided to apply a current to a zone of the sensing device that exhibits an opposition to the current. The opposition may varies in response to the exposure of the non-conducting layer to the analyte.
Variation 12 may include the method according to variation 11 and may include providing a device to monitor changes in the opposition to electrical current. The changes may be processed. A rate of change of the opposition may be determined. A magnitude of change in the opposition may be determined. The rate of change and the magnitude of change may be compared to classify the analyte.
Variation 13 may include the method according to variation 11 and may include providing the non-conductive layer as a polymer that does not conduct the current. A conductive layer may be applied to the non-conductive layer, the conductive layer may conduct the current.
Variation 14 may include the method according to variation 13 and may include providing the lead structure electrically coupled with the conductive layer. The zone may be provided in the conductive layer. The response of the non-conductive layer to the exposure to the analyte may be measured by evaluating changes in the opposition.
Variation 15 may include the method according to variation 14 and may include allowing the non-conductive layer to expand in response to the exposure to the analyte so that the opposition changes in the zone as a result of the expansion.
Variation 16 may include the method according to variation 11 and may include providing the non-conductive layer as an array of different polymers selected to have different responses to the exposure to the analyte.
Variation 17 may include the method according to variation 11 and may include providing a conductive layer overlying a surface of the non-conductive layer with areas of the surface exposed and not covered by the conductive later to tune the sensitivity of the sensing device to the analyte.
Variation 18 may include the method according to variation 11 and may include discerning between the analyte and water vapor by providing the non-conductive layer as a fluorinated polymer.
Variation 19 may include the method according to variation 11 and may include classifying the analyte by comparing a magnitude and a rate of the opposition change to known opposition changes for different types of analytes.
Variation 20 may include the method according to variation 11 and may include quantifying a concentration of the analyte by determining a magnitude of change in the opposition and comparing the magnitude to known magnitudes of change for different concentrations of the analyte.
The above description of select variations within the scope of the invention is merely illustrative in nature and, thus, variations or variants thereof are not to be regarded as a departure from the spirit and scope of the invention.
Claims
1. A product for sensing comprising a non-conductive layer comprising a polymer selected for its responsiveness to a stimulus from one of a selected analyte or a selected group of analytes, the non-conductive layer being non-conductive of an electrical current, a conductive layer in contact with the non-conductive layer and being conductive of the electrical current, a lead for providing an electric current to the conductive layer, and a device detecting at least one property of the conductive layer in response to the stimulus.
2. The product according to claim 1 wherein the conductive layer is in contact with a surface of the non-conductive layer and covers only a portion of the surface so that an area of the surface is exposed directly to the stimulus.
3. The product according to claim 1 wherein the non-conductive layer is comprised of areas of different polymers having different responses to the stimulus.
4. The product according to claim 3 wherein the areas are part of one contiguous structure.
5. The product according to claim 1 wherein the lead comprises a first pair of leads and a second pair of leads, wherein the first pair of leads are spaced from each other at a first distance, and the second pair of leads are spaced from each other at a second distance that is greater than the first so that the first and second pairs of leads communicate a different response to the stimulus.
6. The product according to claim 1 wherein the device comprises a data acquisition module in communication with the lead to collect information on responses to the stimulus.
7. The product according to claim 1 wherein the lead is applied to the conductive layer.
8. The product according to claim 1 wherein the lead is disposed between the conductive layer and the non-conductive layer.
9. The product according to claim 1 wherein the lead comprises a number of spaced apart leads.
10. The product according to claim 1 comprising a semi-permeable layer overlying one of the non-conductive layer or the conductive layer, the semi-permeable layer having a pore size selected to pass the selected analyte or the selected group of analytes.
11. A method of monitoring for an exposure to an analyte comprising: providing a sensing device with a non-conductive layer; providing a lead structure to apply a current to a zone of the sensing device that exhibits an opposition to the current, wherein the opposition varies in response to the exposure of the non-conducting layer to the analyte.
12. A method according to claim 11 comprising a device to monitor changes in the opposition, processing the changes; determining a rate of change of the opposition, determining a magnitude of change in the opposition, and comparing the rate of change and the magnitude of change to classify the analyte.
13. A method according to claim 11 comprising providing the non-conductive layer as a polymer that does not conduct the current, applying a conductive layer to the non-conductive layer, the conductive layer conducting the current.
14. The method according to claim 13 comprising providing the lead structure electrically coupled with the conductive layer, providing the zone in the conductive layer, and measuring the response of the non-conductive layer to the exposure to the analyte by evaluating changes in the opposition.
15. The method according to claim 14 comprising allowing the non-conductive layer to expand in response to the exposure to the analyte as a result of the opposition changes in the zone through the expansion.
16. The method according to claim 11 comprising providing the non-conductive layer as an array of different polymers selected to have different responses to the exposure to the analyte.
17. The method according to claim 11 comprising providing a conductive layer overlying a surface of the non-conductive layer with areas of the surface exposed and not covered by the conductive later to tune the sensitivity of the sensing device to the analyte.
18. The method according to claim 11 comprising discerning between the analyte and water vapor by providing the non-conductive layer as a fluorinated polymer.
19. The method according to claim 11 comprising classifying the analyte by comparing a magnitude and a rate of the opposition change to known opposition changes for different types of analytes.
20. The method according to claim 11 comprising quantifying a concentration of the analyte by determining a magnitude of change in the opposition and comparing the magnitude to known magnitudes of change for different concentrations of the analyte.
Type: Application
Filed: Apr 29, 2016
Publication Date: Jan 5, 2017
Inventors: JAMES R. SALVADOR (ROYAL OAK, MI), DEBEJYO CHAKRABORTY (NOVI, MI), KEVIN H. PETERSON (DETROIT, MI), NILESH D. MANKAME (ANN ARBOR, MI)
Application Number: 15/141,902