Printed Gas Sensor

Abstract

A printed gas sensor is disclosed. The sensor may include a porous substrate, an electrode layer, a liquid or gel electrolyte layer, and an encapsulation layer. The electrode layer comprises two or more electrodes that are formed on one side of the porous substrate. The liquid or gel electrolyte layer is in electrolytic contact with the two or more electrodes. The encapsulation layer encapsulates the electrode layer and electrolyte layer thereby forming an integrated structure with the porous substrate.

1 . A printed sensor comprising:
 an at least partially porous substrate;   an electrode layer, wherein the electrode layer comprises two or more porous electrodes that are formed on one side of said porous substrate;   an electrolyte layer, wherein the electrolyte layer is in electrolytic contact with the electrode layer, wherein the electrolyte layer comprises an liquid, solid, or gel electrolyte; and   an encapsulation layer, wherein the encapsulation layer encapsulates the electrode layer and electrolyte layer thereby forming an integrated structure with the porous substrate.   
     
     
         2 . The sensor of  claim 1 , wherein said porous substrate has an access port for entry of a gas sample to be measured, said gas enters the porous substrate opposite to the porous electrode layer. 
     
     
         3 . The sensor of  claim 2 , wherein said the access port ranges in size from about 0.001″ diameter to about 1.000″ in diameter. 
     
     
         4 . The sensor of  claim 2 , wherein said the access port comprises an array of openings. 
     
     
         5 . The sensor of  claim 2 , wherein said access port is covered by a filter. 
     
     
         6 . The sensor of  claim 5 , wherein said filter comprises a porous polytetrafluoroethylene membrane. 
     
     
         7 . The sensor of  claim 1 , wherein said porous substrate comprises porous polytetrafluoroethylene, porous polyethylene, porous polypropylene, porous polyisobutylene, porous polyester, porous polyurethane, porous polyacrylic, porous fluorine polymer, porous cellulosic polymer, porous fiberglass, or a mixture thereof. 
     
     
         8 . The sensor of  claim 1 , wherein the porous electrodes are formed on said porous substrate by screen printing, gravure printing or inkjet printing. 
     
     
         9 . The sensor of  claim 1 , wherein the porous electrodes comprise a metal catalyst chosen from the group consisting of Pt, Pd, Au, Ag, Ru, Rh, Ir, Co, Fe, Ni, Carbon, Pb, and compounds or alloys or mixtures thereof. 
     
     
         10 . The sensor of  claim 1 , wherein the electrolyte layer is in contact with at least a portion of the electrodes. 
     
     
         11 . The sensor of  claim 1 , wherein the encapsulation layer comprises polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyester, polyurethane, polyacrylic, fluorine polymer, cellulosic polymer, fiberglass, PET, polycarbonate, epoxy or a mixture thereof. 
     
     
         12 . The sensor of  claim 1 , wherein the encapsulation layer further comprises a capillary channel for entry of the electrolyte. 
     
     
         13 . The sensor of  claim 1 , wherein the encapsulation layer further comprises a gas vent hole. 
     
     
         14 . The sensor of  claim 1 , wherein the sensor further comprises a wicking layer. 
     
     
         15 . The sensor of  claim 14 , wherein the wicking layer is screen printed or inkjet printed onto a portion of the electrode layer. 
     
     
         16 . The sensor of  claim 1 , wherein the wicking layer comprises silicates or aluminates. 
     
     
         17 . The sensor of  claim 1 , wherein the sensor has a thickness of less than about 2000 microns. 
     
     
         18 . The sensor of  claim 1 , wherein the encapsulation layer comprises one or more conductive traces. 
     
     
         19 . The sensor of  claim 1 , wherein the porous substrate comprises one or more conductive traces. 
     
     
         20 . A method of manufacturing a printed gas sensor, the method comprising:
 printing two or more porous electrodes onto one side of a porous substrate using a metal catalyst ink;   curing the porous substrate and printed electrodes;   bonding an encapsulation layer to the porous substrate thereby encapsulating at least a portion of the two or more porous electrodes and forming an electrolyte reservoir;   filling the electrolyte reservoir with a liquid or gel electrolyte.   
     
     
         21 . The method of  claim 20 , wherein the encapsulation layer comprises a capillary channel, and wherein the filling the electrolyte reservoir utilizes the capillary channel; and wherein the method further comprises:
 sealing the capillary channel.   
     
     
         22 . The method of  claim 20 , wherein the method further comprises printing a wicking layer onto a portion of the two or more electrodes. 
     
     
         23 . The method of  claim 20 , wherein printing two or more porous electrodes comprises screen printing, gravure, or inkjet printing. 
     
     
         24 . The method of  claim 22 , wherein printing the wicking layer comprises screen printing or inkjet printing. 
     
     
         25 . The method of  claim 20 , wherein bonding an encapsulation layer comprises thermal bonding, chemical bonding, adhesive bonding, ultrasonic bonding, lamination, pressure bonding, o-ring bonding or welding. 
     
     
         26 . The method of  claim 20 , wherein filling the electrolyte reservoir comprises submerging the electrolyte reservoir in an electrolytic solution. 
     
     
         27 . The method of  claim 20 , wherein sealing comprises thermal sealing, chemical sealing, adhesive sealing or welding. 
     
     
         28 . The method of  claim 20 , wherein curing comprises heating, heating in a controlled atmosphere, forced air drying, infrared irradiation, ultraviolet irradiation, vacuum dryingion-beam irradiation, gamma irradiation, and combinations thereof. 
     
     
         29 . The method of  claim 20 , wherein the method further comprises forming a substrate layer from porous polytetrafluoroethylene, porous polyethylene, porous polypropylene, porous polyisobutylene, porous polyester, porous polyurethane, porous polyacrylic, porous fluorine polymer, porous cellulosic polymer, porous fiberglass, or a mixture thereof. 
     
     
         30 . The method of  claim 20 , wherein the method further comprises forming an encapsulation layer comprises polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyester, polyurethane, polyacrylic, fluorine polymer, cellulosic polymer, fiberglass, or a mixture thereof. 
     
     
         31 . A method of manufacturing a printed gas sensor, the method comprising:
 printing two or more porous electrodes onto one side of a porous substrate using a metal catalyst ink;   curing the porous substrate and the printed electrodes;   printing the electrolyte layer;   bonding an encapsulation layer having a capillary channel to the porous substrate thereby encapsulating at least a portion of the two or more porous electrodes and electrolyte layer.   
     
     
         32 . A ink composition for printing an electrode, wherein the ink composition comprises:
 a catalyst metal,   PTFE particles,   a retardant and/or additive.   
     
     
         33 . The ink composition of  claim 32 , wherein the additive is selected from the group consisting of:
 polyvinyl alcohol,   Nicrobraz™,   ethyl acetate, or mixtures thereof;   
       and wherein the additive comprises from about 0 to about 15 percent of the ink composition. 
     
     
         34 . The ink composition of  claim 32 , wherein the additive is selected from the group consisting of:
 polyvinyl alcohol,   Nafion,   Polymers,   carbon nanotubes,   silica particles,   alumina particles, or mixtures thereof;   and wherein the additive comprises from 0 to about 15 percent of the ink composition.   
     
     
         35 . A method for printing an electrode,
 preparing an ink composition, wherein the ink composition comprises a catalyst metal and PTFE particles,   printing the ink composition on a porous PTFE substrate to form an electrode,   curing the printed electrode;   wherein the PTFE particles in the ink composition bond to the PTFE substrate.   
     
     
         36 . The method of  claim 35 , wherein the curing comprises a temperature of between 150 C and 320 C.