Material for establishing solid state contact for ion selective electrodes
First Claim
1. An ion selective solid state sensor, comprising:
- an electrically conductive material providing a reference redox couple, said electrically conductive material including mobile ions having a first charge;
an acrylic polymeric material having immobilized ions and being in direct contact with said electrically conductive material, said immobilized ions having a second charge opposite said first charge, said acrylic polymeric material being provided on said electrically conductive material; and
an ion selective membrane covering said polymeric material, said ion selective membrane comprising an ethylene vinyl acetate polymer, said ethylene vinyl acetate polymer including from about 30 weight percent to about 75 weight percent vinyl acetate monomer and from about 0 percent to about 20 percent by weight plasticizer, and an ion selective material dispersed within said ethylene vinyl acetate polymer, wherein said ion selective membrane is from about 0 percent crystalline to about 10 percent crystalline, and wherein said ion selective membrane is not in direct physical contact with said electrically conductive material but is in contact with said acrylic polymeric material.
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Accused Products
Abstract
A polymeric material which to form a stable, reproducible interface between the ionic and electronic domains of an ion selective sensor, or an ion selective field effect transistor, or the like is provided. When employed in an ion selective sensor, the polymeric material is advantageously provided over a solid internal reference electrode and an ion selective membrane is provided thereover. According to one embodiment, the polymeric material of the invention includes less than about 1.63×1021 immobilized charged sites per gram (less than about 2.72 millaequivalents/gram). According to another embodiment, the polymeric material includes immobilized sites of charge opposite that of mobile ions involved in the redox couple. A preferred polymeric material comprises a copolymer of methacrylamidopropyltrimethylammoniumchloride and methylmethacrylate. In a particularly advantageous embodiment, the ion selective membrane has little or no plasticizer.
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Citations
30 Claims
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1. An ion selective solid state sensor, comprising:
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an electrically conductive material providing a reference redox couple, said electrically conductive material including mobile ions having a first charge; an acrylic polymeric material having immobilized ions and being in direct contact with said electrically conductive material, said immobilized ions having a second charge opposite said first charge, said acrylic polymeric material being provided on said electrically conductive material; and an ion selective membrane covering said polymeric material, said ion selective membrane comprising an ethylene vinyl acetate polymer, said ethylene vinyl acetate polymer including from about 30 weight percent to about 75 weight percent vinyl acetate monomer and from about 0 percent to about 20 percent by weight plasticizer, and an ion selective material dispersed within said ethylene vinyl acetate polymer, wherein said ion selective membrane is from about 0 percent crystalline to about 10 percent crystalline, and wherein said ion selective membrane is not in direct physical contact with said electrically conductive material but is in contact with said acrylic polymeric material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A chemical responsive solid state field effect transducer, comprising:
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a layer of semiconductor material having a surface; a pair of first diffusion regions of a first doping characteristic at said surface, a region of said surface of said layer of semiconductor material existing between said pair of first diffusion regions; a second diffusion region of a second doping characteristic at said region of said surface of said layer of semiconductive material existing between said pair of first diffusion regions; an electrically insulating material provided at said region of said surface of said layer of semiconductor material existing between said pair of first diffusion regions; an acrylic polymeric material in direct contact with said diffusion regions and, having immobilized charged sites provided on said electrically insulating material, said acrylic polymeric material carrying less than about 1.63×
1021 immobilized charged sites per gram, said acrylic polymeric material separated from said diffusion regions by said insulating material;an ion selective membrane provided in direct contact on said acrylic polymeric material, said ion selective membrane comprising an ethylene vinyl acetate polymer including from about 30 weight percent to about 75 weight percent vinyl acetate monomer and from about 0 percent to about 20 percent by weight plasticizer, and an ion selective material dispersed within said ethylene vinyl acetate polymer, wherein said ion selective membrane is from about 0 percent crystalline to about 10 percent crystalline; and an electrically insulating encapsulant sealing said transducer at a sample region while leaving exposed a region of said ion selective membrane for exposure to a sample, wherein said acrylic polymeric material in not in direct physical contact with said sample. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification