Method of making a nitrogen dioxide sensing element
First Claim
1. A method of making an element capable of sensing the presence of nitrogen dioxide in the environment, comprising the steps of heating a film of an electrically non-conductive polyaromatic polymer to a temperature in the range of 540°
- C. to 750°
C. in a non-oxidizng atmosphere to pyrolyze the polymer and render said polymer semi-conductive, and attaching electrical leads at spaced locations to said pyrolyzed film.
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Abstract
A method of making an element for sensing the presence of nitrogen dioxide gas in the environment. The element is formed by heating a film of an electrically non-conductive polyaromatic polymer to a temperature sufficiently high to pyrolyze the polymer and render the polymer semi-conductive. The pyrolyzed film is mounted on an electrically non-conductive base. Electrical leads are attached at spaced locations to the film and are connected in an electrical circuit with a signalling or control mechanism. The presence of nitrogen dioxide gas will cause a change in the electrical characteristics of the film to thereby activate the mechanism. A heating element can be associated with the base to insure constant temperature and humidity conditions.
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Citations
15 Claims
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1. A method of making an element capable of sensing the presence of nitrogen dioxide in the environment, comprising the steps of heating a film of an electrically non-conductive polyaromatic polymer to a temperature in the range of 540°
- C. to 750°
C. in a non-oxidizng atmosphere to pyrolyze the polymer and render said polymer semi-conductive, and attaching electrical leads at spaced locations to said pyrolyzed film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
- C. to 750°
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15. A method of making an element capable of sensing the presence of nitrogen dioxide in the environment, comprising the steps of heating a film of an electrically non-conductive polyaromatic polymer to a temperature in the range of 540°
- C. to 750°
C. in a non-oxidizing atmosphere to pyrolyze the polymer and render said polymer semi-conductive, said polymer being selected from the group consisting of polyamides, polyamideimides, polyimides and polybenzimidazoles, bonding the pyrolyzed film to an electrically non-conductive base and attaching electrical leads at spaced locations to said pyrolyzed film.
- C. to 750°
Specification