Methods of minimizing temperature cross-sensitivity in vapor sensors and compositions therefor
First Claim
1. A method for making a conductometric sensor having a reduced cross-sensitivity to temperature, the method comprising:
- combining materials for a sensor matrix comprising a polymer resin, comprising an octylmethylsiloxane monomer, a first species comprising a first conductive particle, and a second species, wherein at least one of said polymer resin and said first species has one of a positive or a negative first temperature coefficient of resistance associated therewith, and said second species has a second temperature coefficient of resistance, wherein said second temperature coefficient of resistance is opposite to that of said first temperature coefficient of resistance; and
creating a sensor matrix comprising said polymer resin, said first species and said second species, wherein said polymer resin crosslinked and said sensor exhibits a change in resistance when exposed to one or more target analytes;
whereby said matrix exhibits a reduced change in resistance when exposed to variations in temperature.
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Abstract
The present invention relates to methods of making compositions for sensor films used for detecting chemical analytes within sensors, such as polymer-absorption chemiresistors (i.e., conductometric sensors). The sensor films have reduced cross-sensitivity to temperature, while maintaining sensitivity to the chemical analytes. The sensor matrix includes components that are associated with a first temperature coefficient of resistance, such as a polymer resin and/or a first conductive particle. The sensor matrix further comprises a second species, preferably a conductive particle, which has a second temperature coefficient of resistance that is opposite to the first temperature coefficient of resistance. The second species has an opposite influence on a resistance response of the sensor from the first species. In this manner, the sensor matrix exhibits a minimized response in resistance to any changes in temperature.
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Citations
17 Claims
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1. A method for making a conductometric sensor having a reduced cross-sensitivity to temperature, the method comprising:
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combining materials for a sensor matrix comprising a polymer resin, comprising an octylmethylsiloxane monomer, a first species comprising a first conductive particle, and a second species, wherein at least one of said polymer resin and said first species has one of a positive or a negative first temperature coefficient of resistance associated therewith, and said second species has a second temperature coefficient of resistance, wherein said second temperature coefficient of resistance is opposite to that of said first temperature coefficient of resistance; and creating a sensor matrix comprising said polymer resin, said first species and said second species, wherein said polymer resin crosslinked and said sensor exhibits a change in resistance when exposed to one or more target analytes; whereby said matrix exhibits a reduced change in resistance when exposed to variations in temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for improving the responsiveness of a sensor that exhibits a change in resistance when in the presence of one or more target analytes, the method comprising:
creating a sensor matrix comprising a crosslinked polymer resin comprising an octylmethylsiloxane monomer, a first species of conductive particles comprising carbon and having a first temperature coefficient of resistance, and a second species of conductive particles having a second temperature coefficient of resistance, wherein said first temperature coefficient of resistance influences a resistance response of said sensor matrix when exposed to variations in temperature and said second temperature coefficient of resistance has an opposite influence on said resistance response of said sensor matrix, thereby minimizing changes in the resistance of said sensor matrix upon exposure to variations in temperature. - View Dependent Claims (14, 15)
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16. A sensor composition having a reduced temperature cross-sensitivity, the composition comprising:
a sensor matrix comprising a crosslinked siloxane polymer resin comprising an octylmethylsiloxane monomer and a plurality of conductive particles, said plurality of conductive particles comprising a first species including a conductive carbon black having an N2 adsorption of between about 8 to about 25 m2/g and a DBP of about 1 to about 180 ml/100 g that has a positive temperature coefficient of resistance and a second species having a negative temperature coefficient of resistance, thereby minimizing changes in the resistance of said sensor matrix upon exposure to variations in temperature. - View Dependent Claims (17)
Specification