JPH1123508A - Odor sensor - Google Patents
Odor sensorInfo
- Publication number
- JPH1123508A JPH1123508A JP19934397A JP19934397A JPH1123508A JP H1123508 A JPH1123508 A JP H1123508A JP 19934397 A JP19934397 A JP 19934397A JP 19934397 A JP19934397 A JP 19934397A JP H1123508 A JPH1123508 A JP H1123508A
- Authority
- JP
- Japan
- Prior art keywords
- sensitive film
- solvent
- odor
- odor sensor
- conductive polymer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
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- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ガスセンサの一種
であるにおいセンサに関する。本発明のにおいセンサ
は、食品や香料の品質検査、悪臭公害の定量検知、焦げ
臭検知による火災警報機、食品や香料の品質検査、更に
は、人物の追跡、識別、認証や薬物検査等の犯罪捜査等
の、幅広い分野で利用可能である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an odor sensor which is a kind of gas sensor. The odor sensor of the present invention is used for quality inspection of foods and fragrances, quantitative detection of odor pollution, fire alarm by detection of burnt odor, quality inspection of foods and fragrances, and further, tracking, identification, authentication and drug inspection of persons. It can be used in a wide range of fields, such as criminal investigation.
【０００２】[0002]
【従来の技術】においセンサは、空気（又は供給された
ガス）中に含まれるにおい成分がセンサの感応面に付着
することにより生ずる該センサの物理的変化を電気的
（又は光学的）に測定するものである。2. Description of the Related Art An odor sensor electrically (or optically) measures a physical change of an odor component contained in air (or supplied gas) caused by adhering to a sensitive surface of the sensor. Is what you do.
【０００３】上記においセンサとして、従来、感応膜に
金属酸化物半導体を用い、その抵抗値変化を利用するも
のが実用化されている。また、このセンサを複数用いた
「電子鼻」と呼ばれるものが、仏国プライムテック社に
て商品化されている。この種のにおいセンサでは、感応
膜を高温（３５０℃以上）に加熱し、該膜表面に付着し
たにおい成分との間で酸化還元反応を生じさせる。この
過程で電子の移動が起こり、感応膜中の電子密度や空乏
層の厚さが変化して電気抵抗が変化する。Conventionally, as the above-mentioned odor sensor, a sensor using a metal oxide semiconductor for a sensitive film and utilizing a change in resistance value has been put to practical use. A so-called “electronic nose” using a plurality of these sensors is commercialized by Primetech of France. In this type of odor sensor, the sensitive film is heated to a high temperature (350 ° C. or higher) to cause an oxidation-reduction reaction with an odor component attached to the film surface. In this process, electrons move, and the electron density in the sensitive film and the thickness of the depletion layer change, so that the electric resistance changes.
【０００４】従って、金属酸化物半導体の感応膜を利用
したにおいセンサでは、酸化還元反応を生じる物質のみ
しか検出することができず、また、上記温度で熱分解す
る物質は検出できない等、対象物質が極めて限定されて
いた。また、分析時にセンサが上記動作温度まで上昇し
て安定するのを待たなければならず、特に、繰り返し測
定時に長い測定時間を要していた。更には、感応膜表面
の状態が比較的不安定であるため、経時変化が大きく、
信頼性に乏しいという問題もあった。Therefore, an odor sensor using a sensitive film of a metal oxide semiconductor can detect only a substance that causes an oxidation-reduction reaction, and cannot detect a substance that thermally decomposes at the above temperature. Was extremely limited. Further, it is necessary to wait for the sensor to rise to the operating temperature and stabilize at the time of analysis. In particular, a long measurement time is required for repeated measurement. Furthermore, since the state of the sensitive film surface is relatively unstable, the change with time is large,
There was also the problem of poor reliability.
【０００５】これに対し、例えば特開昭６１−１４７１
４５号公報には、導電性高分子を利用したガスセンサが
提案されている。また、感応膜にポリピロールを主体と
した導電性高分子を用い、その抵抗値変化を利用するに
おいセンサが英国アロマスキャン社及びネオトロニクス
社にて商品化されている。このようなセンサでは、感応
膜を常温に維持したまま分析を行なうことができる。On the other hand, for example, Japanese Patent Application Laid-Open No.
No. 45 proposes a gas sensor using a conductive polymer. Further, an odor sensor using a conductive polymer mainly composed of polypyrrole for the sensitive film and utilizing the change in the resistance value has been commercialized by Aromascan and Neotronics in the UK. With such a sensor, analysis can be performed while the sensitive film is maintained at room temperature.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上記従
来のセンサに使用されているポリピロール等の導電性高
分子は、主として電解重合法によって感応膜を形成しな
ければならないため、特に薄膜化する場合の膜厚の制御
が難しく、膜の均一性や再現性において難点があった。
また、任意の形状の感応膜を作成することも難しかっ
た。更には、生産性も劣っていた。However, the conductive polymer such as polypyrrole used in the above-mentioned conventional sensor has to form a sensitive film mainly by an electrolytic polymerization method. It was difficult to control the film thickness, and there was a problem in the uniformity and reproducibility of the film.
Also, it was difficult to form a sensitive film having an arbitrary shape. Furthermore, productivity was poor.
【０００７】ところで、この種のにおいセンサでは、導
電性高分子の種類や同一の導電性高分子であってもドー
ピングする材料によって検出可能なにおい成分の物質が
相違することが知られている。従来のにおいセンサの研
究・開発では、そのような観点に基づき、検出可能なに
おい成分の物質の範囲を広げることに主眼が置かれてい
た。しかしながら、においセンサの将来的な応用分野を
考えると、微量なにおい成分を確実に検出できるように
するために検出感度を向上させることも重要である。こ
の点で、上記従来のにおいセンサは、十分な検出感度を
有しているとは言えなかった。In this type of odor sensor, it is known that the detectable odor component differs depending on the type of the conductive polymer and the doping material even if the conductive polymer is the same. Conventional research and development of odor sensors has focused on expanding the range of detectable odor component substances based on such viewpoints. However, considering the future application field of the odor sensor, it is also important to improve the detection sensitivity in order to reliably detect a trace amount of odor components. In this regard, the conventional odor sensor cannot be said to have sufficient detection sensitivity.
【０００８】本発明は上記課題を解決するために成され
たものであり、その第一の目的とするところは、感応膜
の均一性や再現性が良好であって且つ生産性も高いにお
いセンサを提供することにある。また、第二の目的とす
るところは、検出感度の高いにおいセンサを提供するこ
とにある。The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to provide an odor sensor which has good uniformity and reproducibility of a sensitive film and high productivity. Is to provide. A second object is to provide an odor sensor having high detection sensitivity.
【０００９】[0009]
【課題を解決するための手段及び発明の実施の形態】上
記課題を解決するために成された第一の発明は、絶縁基
板上に形成した二個の電極間に感応膜を設け、該感応膜
にガス中の対象成分が付着した際の前記電極間の抵抗変
化を測定することによりにおいを測定するにおいセンサ
であって、前記感応膜は、所定の溶媒に導電性高分子を
溶解させた溶液を基板上に塗布して形成することを特徴
としている。Means for Solving the Problems and Embodiments of the Invention According to a first aspect of the present invention, there is provided a sensitive film between two electrodes formed on an insulating substrate. An odor sensor for measuring odor by measuring a resistance change between the electrodes when a target component in a gas adheres to the film, wherein the sensitive film is obtained by dissolving a conductive polymer in a predetermined solvent. It is characterized in that the solution is formed by applying the solution on a substrate.
【００１０】すなわち、第一の発明のにおいセンサの感
応膜に利用される導電性高分子は、クロロホルム等の溶
媒に対し可溶性を有する。このため、従来のように電解
重合法に依らず、酸化重合法等により重合したポリマー
を溶媒に溶かし、予め電極を形成した基板上に該溶液を
塗布し、溶媒を揮発させることにより感応膜を形成する
ことができる。このため、感応膜の膜厚の制御が容易で
あり、均一性の高い膜が形成でき、また再現性も良好で
ある。That is, the conductive polymer used for the sensitive film of the odor sensor according to the first invention is soluble in a solvent such as chloroform. Therefore, instead of the conventional electrolytic polymerization method, a polymer polymerized by an oxidative polymerization method or the like is dissolved in a solvent, the solution is applied on a substrate on which electrodes are previously formed, and the solvent is volatilized to form a sensitive film. Can be formed. Therefore, it is easy to control the thickness of the sensitive film, a film with high uniformity can be formed, and the reproducibility is good.
【００１１】上記所定の溶媒としては、例えばクロロホ
ルム、トルエン等の高い揮発性を有する有機溶媒が適当
である。また、該溶媒に可溶性の導電性高分子として
は、例えば、チオフェンの３位に炭素数が４以上のアル
キル基を導入したポリ（３−アルキルチオフェン）を主
鎖とするもの、具体的には、ポリ（３−ブチルチオフェ
ン）、ポリ（３−ヘキシルチオフェン）、ポリ（３−オ
クチルチオフェン）、ポリ（３−デシルチオフェン）、
ポリ（３−ドデシルチオフェン）等を主鎖とする導電性
高分子を利用することができる。また、上記アルキル基
の代わりにアルコキシル基を導入したポリ（３−アルコ
キシルチオフェン）を主鎖とする導電性高分子も利用で
きる。更に、Ｎ−メチルピロリドン（ＮＭＰ）を溶媒に
用いることによりポリアニリン等の導電性高分子を利用
することもできる。As the above-mentioned predetermined solvent, an organic solvent having high volatility such as chloroform and toluene is suitable. Examples of the conductive polymer soluble in the solvent include, for example, those having a main chain of poly (3-alkylthiophene) in which an alkyl group having 4 or more carbon atoms is introduced at the 3-position of thiophene, specifically, , Poly (3-butylthiophene), poly (3-hexylthiophene), poly (3-octylthiophene), poly (3-decylthiophene),
A conductive polymer having poly (3-dodecylthiophene) or the like as a main chain can be used. In addition, a conductive polymer having a main chain of poly (3-alkoxylthiophene) having an alkoxyl group introduced therein instead of the alkyl group can also be used. Furthermore, by using N-methylpyrrolidone (NMP) as a solvent, a conductive polymer such as polyaniline can be used.
【００１２】上記導電性高分子は、高分子主鎖にπ電子
を取り込んだ共役系高分子であって、適当なドーピング
によって導電率を制御できることが知られている。本願
発明者らは、上記導電性高分子を感応膜としたにおいセ
ンサに関する実験の過程で、該センサの応答特性が感応
膜の導電性高分子の導電率に依存することを見い出し
た。The conductive polymer is a conjugated polymer having π electrons incorporated in the polymer main chain, and it is known that the conductivity can be controlled by appropriate doping. In the course of an experiment on an odor sensor using the conductive polymer as a sensitive film, the inventors of the present application have found that the response characteristics of the sensor depend on the conductivity of the conductive polymer of the sensitive film.
【００１３】すなわち、第二の発明は、絶縁基板上に形
成した二個の電極間に感応膜を設け、該感応膜にガス中
の対象成分が付着した際の前記電極間の抵抗変化を測定
することによりにおいを測定するにおいセンサであっ
て、前記感応膜は、導電率が１０-1〜１０-5〔Ｓ／ｃ
ｍ〕である導電性高分子から成ることを特徴としてい
る。That is, a second invention provides a sensitive film between two electrodes formed on an insulating substrate, and measures a resistance change between the electrodes when a target component in a gas adheres to the sensitive film. An odor sensor for measuring an odor by performing the measurement, wherein the sensitive film has a conductivity of 10 -1 to 10 -5 [S / c.
m].
【００１４】このような構造のにおいセンサでは、感応
膜の導電性高分子の導電率が１０-1〜１０-5〔Ｓ／ｃ
ｍ〕の範囲内であるとき、におい成分に対する応答特性
が良好であって検出感度が高い。更に好ましくは、１０
-2〜１０-4〔Ｓ／ｃｍ〕の範囲内であるとき顕著な応答
特性が得られる。このような導電率の範囲で高い検出感
度を得られるのは、上記のように溶媒を用いて感応膜を
形成した場合に限らず、例えば、電解重合法等により形
成された感応膜でも同様である。In the odor sensor having such a structure, the conductivity of the conductive polymer of the sensitive film is 10 -1 to 10 -5 [S / c.
m], the response to odor components is good and the detection sensitivity is high. More preferably, 10
When it is within the range of -2 to 10 -4 [S / cm], a remarkable response characteristic is obtained. The reason that high detection sensitivity can be obtained in such a range of conductivity is not limited to the case where a sensitive film is formed using a solvent as described above, and the same applies to a sensitive film formed by, for example, an electrolytic polymerization method. is there.
【００１５】通常、上記第一の発明に係るにおいセンサ
の感応膜を構成する導電性高分子は、そのままでは導電
率が１０-5〔Ｓ／ｃｍ〕よりも低い。そこで、該第一の
発明のにおいセンサでは、ドーパントを溶媒に溶かし前
記基板上に形成した感応膜に該溶液を接触させることに
より、該感応膜にドーパントを添加して導電率を高める
ことが好ましい。Usually, the conductivity of the conductive polymer constituting the sensitive film of the odor sensor according to the first invention is lower than 10 −5 [S / cm] as it is. Therefore, in the odor sensor of the first invention, it is preferable to dissolve the dopant in a solvent and bring the solution into contact with the sensitive film formed on the substrate, thereby adding the dopant to the sensitive film to increase the conductivity. .
【００１６】ドーパントとしては、例えば、プロトン酸
類（ＨＮＯ3、Ｈ2ＳＯ4、ＨＣｌＯ4、ＨＦ、ＨＣｌ、Ｆ
ＳＯ3Ｈ、ＣＦ3ＳＯ4Ｈ等）、遷移金属ハライド類（Ｆ
ｅＣｌ3、ＭｏＣｌ5、ＷＣｌ5、ＳｎＣｌ4、ＭｏＦ5、
ＲｕＦ5、ＳｎＩ4等）、有機物質（ＴＣＮＱ、ＴＣＮ
Ｅ、クロラニル等）、ポルフェリン類、ポリマー（ポリ
スチレンスルフォン酸、ポリビニルスルフォン酸等）を
利用することができる。As the dopant, for example, protonic acids (HNO 3 , H 2 SO 4 , HClO 4 , HF, HCl, F
SO 3 H, CF 3 SO 4 H), transition metal halides (F
eCl 3 , MoCl 5 , WCl 5 , SnCl 4 , MoF 5 ,
RuF 5 , SnI 4 etc.), organic substances (TCNQ, TCN
E, chloranil, etc.), porpherins, and polymers (polystyrene sulfonic acid, polyvinyl sulfonic acid, etc.) can be used.
【００１７】このようなドーピングにより、導電性高分
子の膜内に比較的自由に移動し電子を運搬するドーパン
トが導入され、導電率が高くなる。このような方法で
は、溶液の濃度や浸漬時間を変えることにより添加する
ドーパント量を制御できるので、導電率を目標値に容易
に近付けることができる。By such doping, a dopant which relatively freely moves and transports electrons is introduced into the conductive polymer film, and the conductivity is increased. In such a method, the amount of dopant to be added can be controlled by changing the concentration of the solution or the immersion time, so that the conductivity can be easily brought close to the target value.
【００１８】また、ドーパントを導入する代わりに、上
記導電性高分子が溶けやすい溶媒と、該溶媒よりも極性
及び誘電率が高く且つ該導電性高分子が溶けにくい溶媒
とを混合した溶媒に該導電性高分子を溶解し、該溶液を
前記基板上に塗布して感応膜を形成するようにしてもよ
い。ここで使用される溶媒は、例えば、上記のような導
電性高分子が可溶である有機溶媒（クロロホルム、トル
エン等）と、該導電性高分子が溶けにくい有機溶媒（テ
トラヒドロフラン、ジメチルホルムアミド、ジメチルス
ルホオキシド、Ｎ−メチルピロリドン等）との組合せた
ものを用いることができる。Instead of introducing a dopant, a solvent obtained by mixing a solvent in which the conductive polymer is easily soluble and a solvent having a higher polarity and dielectric constant than the solvent and in which the conductive polymer is hardly soluble is mixed. The conductive polymer may be dissolved, and the solution may be applied on the substrate to form a sensitive film. The solvent used here includes, for example, an organic solvent in which the conductive polymer is soluble (such as chloroform and toluene) and an organic solvent in which the conductive polymer is hardly soluble (tetrahydrofuran, dimethylformamide, dimethyl Sulfoxide, N-methylpyrrolidone, etc.) can be used.
【００１９】このように形成された感応膜は、規則性を
有するポリマー構造の一部が変形して（例えば、隣接分
子間の距離が変わる等）導電率が上がる。このようなに
おいセンサは、ポリマーの構造変化自体が電気伝導に寄
与するので、ドーパントの脱落等による導電率の経時変
化や不安定さがなく、より安定な状態を長時間維持でき
る。In the sensitive film thus formed, a part of the regular polymer structure is deformed (for example, the distance between adjacent molecules is changed) and the conductivity is increased. In such an odor sensor, since the structural change of the polymer itself contributes to electric conduction, there is no change with time or instability of the conductivity due to dropout of the dopant, and a more stable state can be maintained for a long time.
【００２０】[0020]
〔実施例１〕本発明に係るにおいセンサの第一の実施例
（以下「実施例１」という）を説明する。このにおいセ
ンサは、感応膜として、ポリ（３−ヘキシルチオフェ
ン）に塩化第二鉄をドーパントとして導入したものであ
る。導電性高分子やドーパントとして他のものを利用で
きることは既述の通りである。図１は、実施例１のにお
いセンサ１０の構造の一例を示す平面図（ａ）、該平面
図のＡ部分の拡大図（ｂ）及び断面図（ｃ）である。絶
縁体材料であるガラス基板１１上に金から成る厚さ約１
５０ｎｍの電極１２ａ、１２ｂが５μｍ間隔の櫛形状に
形成され、該電極１２ａ、１２ｂにリード線１３ａ、１
３ｂが接続されている。基板１１及び電極１２ａ、１２
ｂの材料は上記のものに限定されない。基板１１上に
は、電極１２ａ、１２ｂを被覆してポリ（３−ヘキシル
チオフェン）から成る感応膜１４が形成されている。こ
の感応膜１４には、後記の方法により塩化第二鉄がドー
パントとして導入されている。[Embodiment 1] A first embodiment (hereinafter referred to as "embodiment 1") of an odor sensor according to the present invention will be described. This odor sensor is obtained by introducing ferric chloride as a dopant into poly (3-hexylthiophene) as a sensitive film. As described above, other conductive polymers and dopants can be used. FIG. 1 is a plan view (a) showing an example of the structure of the odor sensor 10 according to the first embodiment, and an enlarged view (b) and a cross-sectional view (A) of a portion A in the plan view. A thickness of about 1 made of gold is formed on a glass substrate 11 which is an insulator material.
The electrodes 12a and 12b of 50 nm are formed in a comb shape at intervals of 5 μm, and the electrodes 12a and 12b are connected to the lead wires 13a and 1b.
3b is connected. Substrate 11 and electrodes 12a, 12
The material of b is not limited to the above. On the substrate 11, a sensitive film 14 made of poly (3-hexylthiophene) is formed so as to cover the electrodes 12a and 12b. To the sensitive film 14, ferric chloride is introduced as a dopant by a method described later.
【００２１】上記においセンサ１０の製造方法の一例は
次の通りである。まず、ガラス基板１１上にリフトオフ
法によって電極１２ａ、１２ｂを形成する。一方、チオ
フェンＣ4Ｈ4Ｓの３位をヘキシル基Ｃ6Ｈ13に置換した
３−ヘキシルチオフェン（東京化成社製）を酸化重合法
により重合してポリ（３−ヘキシルチオフェン）を作成
し、これをクロロホルムの溶媒に溶解して濃度０．１ｍ
ｏｌ／Ｌの溶液を作成する。この溶液を上記基板１１上
にスピンコート法にて塗布し、膜厚３００ｎｍ程度の膜
体を形成する。このような膜体を形成するには、例え
ば、回転数１５００ｒｐｍで１０秒間スピナーを動作さ
せるとよい。その後、ニトロメタン溶媒に塩化第二鉄Ｆ
ｅＣｌ3を溶解して濃度０．１ｍｏｌ／Ｌの溶液を作成
し、その溶液中に上記膜体を形成した基板を１０分間浸
漬する。これにより、適度な量の塩化第二鉄がポリ（３
−ヘキシルチオフェン）膜中にドーパントとして導入さ
れ感応膜１４ができあがる。なお、リード線１３ａ、１
３ｂは感応膜１４を形成した後に所定箇所の膜を除去し
て電極１２ａ、１２ｂに接続してもよいし、予め該所定
箇所に膜が形成されないようにしておいてもよい。An example of a method for manufacturing the above-mentioned odor sensor 10 is as follows. First, electrodes 12a and 12b are formed on a glass substrate 11 by a lift-off method. On the other hand, 3- (hexylthiophene) (manufactured by Tokyo Chemical Industry Co., Ltd.) in which the 3-position of thiophene C 4 H 4 S is substituted with a hexyl group C 6 H 13 is polymerized by an oxidative polymerization method to form poly (3-hexylthiophene). This was dissolved in a chloroform solvent to give a concentration of 0.1 m.
Make an ol / L solution. This solution is applied onto the substrate 11 by spin coating to form a film having a thickness of about 300 nm. In order to form such a film, for example, the spinner may be operated at a rotation speed of 1500 rpm for 10 seconds. Then, ferric chloride F was added to nitromethane solvent.
eCl 3 is dissolved to prepare a solution having a concentration of 0.1 mol / L, and the substrate on which the film is formed is immersed in the solution for 10 minutes. As a result, an appropriate amount of ferric chloride is converted to poly (3
-Hexylthiophene) is introduced as a dopant into the film, and the sensitive film 14 is completed. The lead wires 13a, 1
3b, after forming the sensitive film 14, the film at a predetermined location may be removed and connected to the electrodes 12a and 12b, or the film may not be formed at the predetermined location in advance.
【００２２】基板１１上にポリ（３−ヘキシルチオフェ
ン）の膜体を形成した状態では、その導電率は１０
-7〔Ｓ／ｃｍ〕以下の低い値であるが、上記のようにド
ーパントを膜中に導入することにより、１０-2〜１０-4
〔Ｓ／ｃｍ〕の範囲の好ましい導電率にすることができ
る。In the state where a poly (3-hexylthiophene) film is formed on the substrate 11, its conductivity is 10
-7 [S / cm] or less, but 10 −2 to 10 −4 by introducing a dopant into the film as described above.
A preferable conductivity in the range of [S / cm] can be obtained.
【００２３】図２は、上記においセンサ１０のガス応答
を調べるための評価装置の構成図である。清浄空気の流
路２０には、バルブ２１、フローセル２３、ポンプ２４
が設けられ、該ポンプ２４の吸引によって流路２０に清
浄空気が流通する。バルブ２１にはにおい物質容器２２
に連なるガス流路が接続されており、バルブ２１の操作
により清浄空気中に適宜量のにおい成分ガスが混入され
るようにしている。フローセル２３内には上記においセ
ンサ１０が配置され、該センサ１０の電極の抵抗変化を
抵抗計２５にて測定する。FIG. 2 is a configuration diagram of an evaluation device for examining the gas response of the odor sensor 10. A valve 21, a flow cell 23, a pump 24
Is provided, and clean air flows through the flow path 20 by suction of the pump 24. The valve 21 has an odor substance container 22.
The gas flow path is connected to the gas flow passage, and an appropriate amount of odor component gas is mixed into the clean air by operating the valve 21. The odor sensor 10 is disposed in the flow cell 23, and a resistance change of an electrode of the sensor 10 is measured by a resistance meter 25.
【００２４】まず、乾燥剤（シリカゲル）、活性炭及び
モレキュラシーブスを通過した後の清浄空気を２００ｍ
Ｌ／分の流速で１０秒間流し、これによりセンサ１０の
感応膜に付着している不純物を脱離させて除去する。そ
の後、清浄空気ににおい成分として酢酸ブチルを混入さ
せたガスを同じ流速で３０秒間流す。そして、最後に再
び清浄空気のみを流す。上記手順の間に、センサ１０の
電極間の抵抗を抵抗計２５により連続的に測定する。First, 200 m of clean air after passing through a desiccant (silica gel), activated carbon and molecular sieves.
The flow is performed at a flow rate of L / min for 10 seconds, whereby impurities adhering to the sensitive film of the sensor 10 are desorbed and removed. Thereafter, a gas in which butyl acetate is mixed as a smell component is flowed at 30 s at the same flow rate in clean air. Finally, only the clean air is flown again. During the above procedure, the resistance between the electrodes of the sensor 10 is continuously measured by the ohmmeter 25.
【００２５】図３は、本実施例１のにおいセンサ１０の
応答特性の実測結果を示す図である。図３に示されてい
るように、１０秒経過後ににおい成分を含むガスが流れ
始めると即座且つ急峻に抵抗値が上昇する。つまり、検
出の応答速度は極めて迅速である。また、におい成分の
有無に対する抵抗値の差異は大きいので、検出感度も高
く、微量のにおい成分の検出にも有効であることがわか
る。FIG. 3 is a diagram showing actual measurement results of response characteristics of the odor sensor 10 of the first embodiment. As shown in FIG. 3, when the gas containing the odor component starts flowing after 10 seconds, the resistance value increases immediately and steeply. That is, the response speed of the detection is extremely fast. In addition, since the difference between the resistance value and the presence or absence of the odor component is large, the detection sensitivity is high, and it can be seen that it is effective for detecting a trace amount of odor component.
【００２６】次に、におい成分に対する応答率と感応膜
１４の導電率との関係を調べた。ここで、応答率とは、
におい成分を与えたときと与えないときとの抵抗の変化
率を意味する。導電率の相違する感応膜を有するにおい
センサを作成するには、塩化第二鉄の濃度の相違する複
数の溶液を作成し、該溶液にポリ（３−ヘキシルチオフ
ェン）膜を形成した基板をそれぞれ同一時間浸漬するこ
とにより、ドーパントの導入を変えた。図４は、このよ
うにして作成した複数のにおいセンサ（形状は同一）の
応答率の実測結果を示す図である。図４より、導電率が
１０-1〜１０-5〔Ｓ／ｃｍ〕の範囲で約１０％以上の応
答率が得られていることがわかる。更に、導電率が１０
-2〜１０-4〔Ｓ／ｃｍ〕の範囲において２０％以上の高
い応答率が得られていることがわかる。上述のような感
応膜の形成方法では、このような高い応答率を示す導電
率に容易に制御することができる。Next, the relationship between the response rate to the odor component and the conductivity of the sensitive film 14 was examined. Here, the response rate is
It means the rate of change in resistance between when an odor component is given and when it is not given. In order to prepare an odor sensor having a sensitive film having a different conductivity, a plurality of solutions having different concentrations of ferric chloride are prepared, and a substrate having a poly (3-hexylthiophene) film formed on the solution is prepared. By soaking for the same time, the introduction of the dopant was changed. FIG. 4 is a diagram showing actual measurement results of the response rates of a plurality of odor sensors (having the same shape) created in this way. FIG. 4 shows that a response rate of about 10% or more was obtained when the conductivity was in the range of 10 -1 to 10 -5 [S / cm]. Furthermore, the conductivity is 10
It can be seen that a high response rate of 20% or more was obtained in the range of -2 to 10 -4 [S / cm]. In the method for forming a sensitive film as described above, the conductivity showing such a high response rate can be easily controlled.
【００２７】〔実施例２〕次に、本発明に係るにおいセ
ンサの他の実施例（以下「実施例２」という）を説明す
る。上記実施例１は導電率を上げるためにドーピングを
用いていたが、本実施例２は、膜体自体の形成方法を変
えることにより、規則性を有するポリマー構造の一部を
変形させたりポリマー間距離を変化させたりして導電率
を上げるものである。[Second Embodiment] Next, another embodiment of the odor sensor according to the present invention (hereinafter referred to as "second embodiment") will be described. In Example 1 described above, doping was used to increase the electrical conductivity. In Example 2, however, by changing the method of forming the film body itself, a part of the polymer structure having regularity was deformed or the interpolymer was formed. The conductivity is increased by changing the distance.
【００２８】本実施例２のにおいセンサ１０の製造方法
の一例は次の通りである。まず、実施例１と同様に、ガ
ラス基板１１上に電極１２ａ、１２ｂを形成する。ま
た、３−ヘキシルチオフェン（東京化成社製）を酸化重
合法により重合してポリ（３−ヘキシルチオフェン）を
作成し、これをクロロホルムとジメチルスルホキシドの
混合溶液（割合は９：１）に濃度０．１ｍｏｌ／Ｌで溶
解させる。そして、この溶液を実施例１と同じ要領にて
基板１１上にスピンコートし、基板１１及び電極１２
ａ、１２ｂを被覆する膜体を形成する。実施例２では、
この膜体がそのまま感応膜１４となる。ポリ（３−ヘキ
シルチオフェン）に対しクロロホルムは可溶性溶媒であ
り、ジメチルスルホキシドは不溶性溶媒である。また、
後者は前者よりも高い極性及び誘電率を有する。An example of a method for manufacturing the odor sensor 10 according to the second embodiment is as follows. First, as in the first embodiment, electrodes 12a and 12b are formed on a glass substrate 11. Further, poly (3-hexylthiophene) was prepared by polymerizing 3-hexylthiophene (manufactured by Tokyo Chemical Industry Co., Ltd.) by an oxidative polymerization method, and the poly (3-hexylthiophene) was added to a mixed solution of chloroform and dimethylsulfoxide (at a ratio of 9: 1) at a concentration of 0%. Dissolve at 1 mol / L. Then, this solution is spin-coated on the substrate 11 in the same manner as in the first embodiment.
a, and a film body covering 12b is formed. In the second embodiment,
This film body becomes the sensitive film 14 as it is. Chloroform is a soluble solvent for poly (3-hexylthiophene), and dimethylsulfoxide is an insoluble solvent. Also,
The latter has higher polarity and dielectric constant than the former.
【００２９】上記方法により形成された感応膜１４のポ
リマー構造は完全に解明されているわけではないが、規
則性を有して配列されるポリマーの構造の一部が欠落し
たりポリマー間の距離が変化したりすることにより、ポ
リマー内部を電子が移動し易くなって導電率が上がると
推定される。Although the polymer structure of the sensitive film 14 formed by the above method has not been completely elucidated, a part of the structure of the polymer arranged with regularity is lost or the distance between the polymers is reduced. It is presumed that, due to a change in the conductivity, electrons easily move inside the polymer and the conductivity increases.
【００３０】図５は、本実施例２のにおいセンサの応答
特性の実測結果を示す図である。測定方法は図３の方法
と同一である。図５よりわかるように、１０秒経過後に
におい成分を含むガスが流れ始めると、即座且つ急峻に
抵抗値が上昇している。また、におい成分の有無に対す
る抵抗値の差異も実施例１と同様に大きいので、高い検
出感度が得られる。FIG. 5 is a diagram showing the results of actual measurement of the response characteristics of the odor sensor according to the second embodiment. The measuring method is the same as the method in FIG. As can be seen from FIG. 5, when the gas containing the odor component starts flowing after 10 seconds, the resistance value increases immediately and steeply. Further, since the difference in resistance value between the presence and absence of the odor component is large as in the case of the first embodiment, high detection sensitivity can be obtained.
【００３１】上記実施例１のにおいセンサでは、主とし
て添加されたドーパントが電気伝導に寄与するため、例
えば、時間経過に伴いドーパントが感応膜から脱落して
その量が減少すると、導電率が低くなる傾向にある。し
かしながら、本実施例２のにおいセンサでは、主として
ポリマーの構造変化が電気伝導に寄与するため、時間経
過に対してより安定な感応膜１４が形成される。図６
は、実施例１のセンサと実施例２のセンサとの抵抗安定
性の実測結果を示す図である。図６より、実施例２のセ
ンサはより抵抗の経時変化が小さく、より安定であるこ
とがわかる。In the odor sensor of the first embodiment, the added dopant mainly contributes to the electric conduction. For example, when the amount of the dopant drops from the sensitive film with the lapse of time and the amount decreases, the conductivity decreases. There is a tendency. However, in the odor sensor of the second embodiment, since the structural change of the polymer mainly contributes to electric conduction, the sensitive film 14 that is more stable with the passage of time is formed. FIG.
FIG. 8 is a diagram showing the results of actual measurement of the resistance stability of the sensor according to the first embodiment and the sensor according to the second embodiment. FIG. 6 shows that the sensor of Example 2 has a smaller change in resistance with time and is more stable.
【００３２】なお、上記実施例において、においセンサ
の形状や寸法等は適宜に変えることができる。また、製
造時の濃度等の各数値も適宜に変えることができる。In the above embodiment, the shape and size of the odor sensor can be appropriately changed. Further, each numerical value such as the concentration at the time of manufacturing can be appropriately changed.
【００３３】[0033]
【発明の効果】以上の説明のように、第一の発明に係る
においセンサでは、導電性高分子を溶解させた溶液を基
板上に塗布し乾燥させることにより該導電性高分子から
成る感応膜を形成することができる。このため、膜厚の
制御が容易であって、均一性や再現性が極めて良好であ
る。また、このにおいセンサは、常温でにおい成分を検
出できるので、熱分解し易い成分も検出することができ
る。As described above, in the odor sensor according to the first aspect of the present invention, a solution in which a conductive polymer is dissolved is applied to a substrate and dried to form a sensitive film made of the conductive polymer. Can be formed. Therefore, control of the film thickness is easy, and uniformity and reproducibility are extremely good. Further, since this odor sensor can detect odor components at normal temperature, it can also detect components that are easily thermally decomposed.
【００３４】また、第二の発明に係るにおいセンサで
は、感応膜として利用する導電性高分子の導電率を適正
に制御したので、におい成分に対して高い応答特性を得
ることができる。In the odor sensor according to the second aspect of the present invention, since the conductivity of the conductive polymer used as the sensitive film is appropriately controlled, high response characteristics to odor components can be obtained.
【００３５】また、ドーパントを溶媒に溶かし基板上に
形成した感応膜に該溶液を接触させることにより感応膜
の導電率を高めるようにすれば、高い応答特性を示すセ
ンサを得ることができる。Further, if the conductivity of the sensitive film is increased by dissolving the dopant in a solvent and bringing the solution into contact with the sensitive film formed on the substrate, a sensor having high response characteristics can be obtained.
【００３６】更には、導電性高分子が溶けやすい溶媒
と、該溶媒よりも極性及び誘電率が高く且つ該導電性高
分子が溶けにくい溶媒とを混合した溶媒に該導電性高分
子を溶解させた溶液を基板上に塗布して感応膜を形成す
ることにより導電率を高めるようにすれば、高い応答特
性を示すと共に経時変化の少ない安定したセンサを得る
ことができる。Further, the conductive polymer is dissolved in a solvent obtained by mixing a solvent in which the conductive polymer is easily soluble and a solvent having higher polarity and dielectric constant than the solvent and in which the conductive polymer is hardly soluble. If the conductivity is increased by forming a sensitive film by coating the solution on a substrate, a stable sensor having high response characteristics and little change over time can be obtained.
【図１】 本発明の一実施例であるにおいセンサの構成
図。FIG. 1 is a configuration diagram of an odor sensor according to an embodiment of the present invention.
【図２】 においセンサの評価装置の構成図。FIG. 2 is a configuration diagram of an odor sensor evaluation device.
【図３】 実施例１のにおいセンサの応答特性を示す
図。FIG. 3 is a diagram illustrating response characteristics of the odor sensor according to the first embodiment.
【図４】 導電率の相違によるにおいセンサの応答率の
相違を示す図。FIG. 4 is a diagram showing a difference in response rate of an odor sensor due to a difference in conductivity.
【図５】 実施例２のにおいセンサの応答特性を示す
図。FIG. 5 is a diagram showing response characteristics of the odor sensor according to the second embodiment.
【図６】 実施例２のにおいセンサの抵抗の経時変化を
示す図。FIG. 6 is a diagram showing a change with time of the resistance of the odor sensor of Example 2.
１１…基板 １２ａ、１２ｂ…電極 １３ａ、１３ｂ…リード線 １４…感応膜 DESCRIPTION OF SYMBOLS 11 ... Substrate 12a, 12b ... Electrode 13a, 13b ... Lead wire 14 ... Sensitive film
Claims (4)
応膜を設け、該感応膜にガス中の対象成分が付着した際
の前記電極間の抵抗変化を測定することによりにおいを
測定するにおいセンサであって、 前記感応膜は、所定の溶媒に導電性高分子を溶解させた
溶液を基板上に塗布して形成することを特徴とするにお
いセンサ。An odor is measured by providing a sensitive film between two electrodes formed on an insulating substrate and measuring a resistance change between the electrodes when a target component in a gas adheres to the sensitive film. An odor sensor, wherein the sensitive film is formed by applying a solution in which a conductive polymer is dissolved in a predetermined solvent on a substrate.
応膜を設け、該感応膜にガス中の対象成分が付着した際
の前記電極間の抵抗変化を測定することによりにおいを
測定するにおいセンサであって、 前記感応膜は、導電率が１０-1〜１０-5〔Ｓ／ｃｍ〕で
ある導電性高分子から成ることを特徴とするにおいセン
サ。2. A smell is measured by providing a sensitive film between two electrodes formed on an insulating substrate and measuring a resistance change between the electrodes when a target component in a gas adheres to the sensitive film. An odor sensor, wherein the sensitive film is made of a conductive polymer having a conductivity of 10 -1 to 10 -5 [S / cm].
形成した感応膜に該溶液を接触させることにより、該感
応膜にドーパントを添加して導電率を高めたことを特徴
とする請求項１に記載のにおいセンサ。3. The method according to claim 1, wherein the dopant is dissolved in a solvent and the solution is brought into contact with the sensitive film formed on the substrate, whereby the conductivity is increased by adding the dopant to the sensitive film. Odor sensor as described.
該溶媒よりも極性及び誘電率が高く且つ該導電性高分子
が溶けにくい溶媒とを混合した溶媒に該導電性高分子を
溶解させた溶液を、前記基板上に塗布して感応膜を形成
することにより導電率を高めたことを特徴とする請求項
１に記載のにおいセンサ。4. A solvent in which the conductive polymer is easily soluble,
A solution in which the conductive polymer is dissolved in a solvent obtained by mixing a solvent having a higher polarity and dielectric constant than the solvent and in which the conductive polymer is hardly soluble is applied on the substrate to form a sensitive film. The odor sensor according to claim 1, wherein the conductivity is increased by doing so.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19934397A JP3755247B2 (en) | 1997-07-08 | 1997-07-08 | Odor sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19934397A JP3755247B2 (en) | 1997-07-08 | 1997-07-08 | Odor sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1123508A true JPH1123508A (en) | 1999-01-29 |
| JP3755247B2 JP3755247B2 (en) | 2006-03-15 |
Family
ID=16406206
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19934397A Expired - Fee Related JP3755247B2 (en) | 1997-07-08 | 1997-07-08 | Odor sensor |
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| Country | Link |
|---|---|
| JP (1) | JP3755247B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007265658A (en) * | 2006-03-27 | 2007-10-11 | Denso Corp | Electric storage element module |
| JP2018189427A (en) * | 2017-04-28 | 2018-11-29 | 富士通株式会社 | Gas sensor device, gas sensor system, and gas sensor device manufacturing method |
| EP3379240A4 (en) * | 2015-11-17 | 2019-05-01 | Aroma Bit, Inc. | Odor sensor and odor measurement system |
| KR20190079244A (en) * | 2017-12-27 | 2019-07-05 | 동국대학교 산학협력단 | Electronic devices and thin film transistor for gas sensing using the additives |
| US11271161B2 (en) | 2017-08-22 | 2022-03-08 | Fujitsu Limited | Gas sensor, gas measurement apparatus, fabrication method for gas sensor and hydrogen sulfide concentration measurement method |
-
1997
- 1997-07-08 JP JP19934397A patent/JP3755247B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007265658A (en) * | 2006-03-27 | 2007-10-11 | Denso Corp | Electric storage element module |
| EP3379240A4 (en) * | 2015-11-17 | 2019-05-01 | Aroma Bit, Inc. | Odor sensor and odor measurement system |
| US11073491B2 (en) | 2015-11-17 | 2021-07-27 | Aroma Bit, Inc. | Odor sensor and odor measurement system |
| US11796497B2 (en) | 2015-11-17 | 2023-10-24 | Aroma Bit, Inc. | Odor sensor and odor measurement system |
| JP2018189427A (en) * | 2017-04-28 | 2018-11-29 | 富士通株式会社 | Gas sensor device, gas sensor system, and gas sensor device manufacturing method |
| US11714057B2 (en) | 2017-04-28 | 2023-08-01 | Fujitsu Limited | Method of manufacturing gas sensor device |
| US11271161B2 (en) | 2017-08-22 | 2022-03-08 | Fujitsu Limited | Gas sensor, gas measurement apparatus, fabrication method for gas sensor and hydrogen sulfide concentration measurement method |
| KR20190079244A (en) * | 2017-12-27 | 2019-07-05 | 동국대학교 산학협력단 | Electronic devices and thin film transistor for gas sensing using the additives |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3755247B2 (en) | 2006-03-15 |
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