Humidity sensor and method for manufacturing the same

A humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap,

• said humidity sensitive thin film comprising a copolymer of a monomer of the following formula (1) with an acrylic monomer having an alkoxysilyl group,
• wherein A11 is a divalent group, each of R11, R12, R13 and R14 which may be the same or different is an alkyl group, each of Y11 and Y12 which may be the same or different is a monovalent group terminated with an unsaturated reactive group, any two or more of R11 to R14, Y11, Y12, A11 and portions thereof adjoining the nitrogen (N) atom may bond together to form a ring with the nitrogen (N) atom, and each of X11− and X12− which may be the same or different is an anion.

A method for preparing a humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, said method comprising the steps of previously treating the insulating substrate with an acrylic monomer having an alkoxysilyl group for joining acrylic functional groups to the insulating substrate, coating a monomer of the following formula (1), then causing the monomer to polymerize to form the humidity sensitive thin film,

• wherein A11 is a divalent group, each of R11, R12, R13 and R14 which may be the same or different is an alkyl group, each of Y11 and Y12 which may be the same or different is a monovalent group terminated with an unsaturated reactive group, any two or more of R11 to R14, Y11, Y12, A11 and portions thereof adjoining the nitrogen (N) atom may bond together to form a ring with the nitrogen (N) atom, and each of X11− and X12− which may be the same or different is an anion.

A method for preparing a humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, said method comprising the steps of coating a monomer of the following formula (1) and an acrylic monomer having an alkoxysilyl group onto the insulating substrate, causing the monomers to copolymerize into a copolymer, and causing the alkoxysilyl groups to react with functional groups on the surface of the insulating substrate in the presence of water vapor to secure the copolymer to the insulating substrate, for thereby forming the humidity sensitive thin film,

• wherein A11 is a divalent group, each of R11, R12, R13 and R14 which may be the same or different is an alkyl group, each of Y11 and Y12 which may be the same or different is a monovalent group terminated with an unsaturated reactive group, any two or more of R11 to R14, Y11, Y12, A11 and portions thereof adjoining the nitrogen (N) atom may bond together to form a ring with the nitrogen (N) atom, and each of X11− and X12− which may be the same or different is an anion.

A humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, wherein said insulating substrate is an insulating substrate from which contaminants and/or oxides on its uppermost surface layer have been removed by physical means, and said humidity sensitive thin film comprises a polymer resulting from a monomer of the following formula (1):

• wherein A11 is a divalent group, each of R11, R12, R13 and R14 which may be the same or different is an alkyl group, each of Y11 and Y12 which may be the same or different is a monovalent group terminated with an unsaturated reactive group, any two or more of R11 to R14, Y11, Y12, A11 and portions thereof adjoining the nitrogen (N) atom may bond together to form a ring with the nitrogen (N) atom, each of X11− and X12− which may be the same or different is an anion.

A method for preparing a humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, said method comprising the steps of removing contaminants and/or oxides on the uppermost surface layer of the insulating substrate by physical means, then coating a monomer of the following formula (1) onto the insulating substrate, and causing the monomer to copolymerize on the insulating substrate for thereby forming the humidity sensitive thin film:

• wherein A11 is a divalent group, each of R11, R12, R13 and R14 which may be the same or different is an alkyl group, each of Y11 and Y12 which may be the same or different is a monovalent group terminated with an unsaturated reactive group, any two or more of R11 to R14, Y11, Y12, A11 and portions thereof adjoining the nitrogen (N) atom may bond together to form a ring with the nitrogen (N) atom, and each of X11− and X12− which may be the same or different is an anion.

A method for preparing a humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, said method comprising the steps of removing oxides and optionally contaminants on the uppermost surface layer of the insulating substrate by physical means, then coating a monomer having an ethylenically unsaturated reactive group onto the insulating substrate, and causing the monomer to copolymerize on the insulating substrate for thereby forming the humidity sensitive thin film.

A humidity sensor device comprising an insulating substrate, a pair of opposed electrodes disposed on the substrate to define a gap therebetween, and a humidity sensitive thin film lying on the gap, wherein said the insulating substrate is an insulating substrate from which oxides and optionally contaminants on its uppermost surface layer have been removed by physical means, and said humidity sensitive thin film comprises a polymer resulting from a monomer having an ethylenically unsaturated reactive group.