Method and apparatus for producing conductive polymer film

Abstract

A method for producing a conductive polymer film, using an apparatus comprising a prism having a working electrode, a light-emitting means and a light probe disposed on both sides of the prism, a container attached to the prism in a liquid-tight manner with its open side facing the working electrode, an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, which is contained in the container, a counter electrode immersed in the electrolytic solution, a power supply means connected to the working electrode and the counter electrode, and a controller connected to the light probe and the power supply means, the method comprising (1) forming the conductive polymer film on the working electrode by supplying current from the power supply means to the working electrode and the counter electrode, while projecting light to the prism, (2) determining an absorption spectrum from the light reflected by the conductive polymer film, (3) storing the relation between the absorbance of the conductive polymer film obtained from the absorption spectrum and a parameter of the conductive polymer film in the controller, and (4) controlling current supply to the working electrode and the counter electrode based on the relation of the absorbance and the parameter to obtain a desired parameter.

1 . A method for producing a conductive polymer film, using an apparatus comprising a prism having a working electrode formed on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, the method comprising (1) forming said conductive polymer film on said working electrode by supplying current from said power supply means to said working electrode and said counter electrode, while projecting light from said light-emitting means to said prism, (2) determining an absorption spectrum by said light probe from the light reflected by said conductive polymer film, which exits from said prism, (3) storing the relation between the absorbance of said conductive polymer film obtained from said absorption spectrum and a parameter of said conductive polymer film in said controller, and (4) controlling current supply to said working electrode and said counter electrode based on the relation of the absorbance and the parameter by said controller to obtain a desired parameter. 
     
     
         2 . The method for producing a conductive polymer film according to  claim 1 , wherein said parameter is the thickness of said conductive polymer film, and wherein said relation is expressed by a calibration curve of the thickness and absorbance of said conductive polymer film. 
     
     
         3 . A method for changing the oxidation/reduction state of a conductive polymer film, using an apparatus comprising a prism having said conductive polymer film formed on a working electrode provided on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, the method comprising (1) changing the oxidation/reduction state of said conductive polymer film by supplying current from said power supply means to said working electrode and said counter electrode, while projecting light from said light-emitting means to said prism, (2) determining an absorption spectrum by said light probe from the light reflected by said conductive polymer film, which exits from said prism, (3) storing the relation between the absorbance of the conductive polymer film obtained from the absorption spectrum and the oxidation/reduction state of said conductive polymer film in said controller, and (4) controlling current supply to said working electrode and said counter electrode based on the relation of the absorbance and the oxidation/reduction state by said controller to obtain a desired oxidation/reduction state. 
     
     
         4 . A method for producing a conductive polymer film at a constant film-forming speed, using an apparatus comprising a prism having a working electrode formed on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, the method comprising (1) forming said conductive polymer film on said working electrode by supplying current from said power supply means to said working electrode and said counter electrode, while projecting light from said light-emitting means to said prism, (2) determining an absorption spectrum by said light probe from the light reflected by said conductive polymer film, which exits from said prism, (3) determining the relation between the time period of forming said conductive polymer film and the thickness of said conductive polymer film from the relation between the change of absorbance with time obtained from said absorption spectrum and the thickness of said conductive polymer film, at plural current levels, (4) determining the relation between current and the film-forming speed in a short time interval from the relation between the time period of forming said conductive polymer film and the thickness of said conductive polymer film at each current level, and storing it in said controller, and (5) controlling the current based on said relation of current and the film-forming speed, such that the speed of forming said conductive polymer film is constant. 
     
     
         5 . An apparatus for producing a conductive polymer film, comprising a prism having a working electrode formed on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, (a) said power supply means supplying current to said working electrode and said counter electrode to form said conductive polymer film on said working electrode, while projecting light from said light-emitting means to said prism, (b) said light probe obtaining an absorption spectrum from the light reflected by said conductive polymer film, which exits from said prism, (c) said controller storing the relation between the absorbance of said conductive polymer film obtained from said absorption spectrum and a parameter of said conductive polymer film, and (d) said controller controlling current supply to said working electrode and said counter electrode based on the relation of the absorbance and the parameter to obtain a desired parameter. 
     
     
         6 . An apparatus for changing the oxidation/reduction state of a conductive polymer film, comprising a prism having said conductive polymer film formed on a working electrode provided on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, (a) said power supply means supplying current to said working electrode and said counter electrode, while projecting light from said light-emitting means to said prism, (b) said light probe obtaining an absorption spectrum from the light reflected by said conductive polymer film, which exits from said prism, (c) said controller storing the relation between the absorbance of said conductive polymer film obtained from said absorption spectrum and the oxidation/reduction state of said conductive polymer film, and (d) said controller controlling current supply to said working electrode and said counter electrode based on the relation of the absorbance and the oxidation/reduction state to obtain a desired oxidation/reduction state. 
     
     
         7 . An apparatus for producing a conductive polymer film at a constant film-forming speed, comprising a prism having a working electrode formed on its one surface, a light-emitting means and a light probe disposed on both sides of said prism, a container attached to said prism in a liquid-tight manner with its open side facing said working electrode, an electrolytic solution containing a conductive-polymer-forming monomer and a dopant, which is contained in said container, a counter electrode immersed in said electrolytic solution, a power supply means connected to said working electrode and said counter electrode, and a controller connected to said light probe and said power supply means, (a) said power supply means supplying current to said working electrode and said counter electrode to form said conductive polymer film on said working electrode, while projecting light from said light-emitting means to said prism, (b) said light probe obtaining an absorption spectrum from the light reflected by said conductive polymer film, which exits from said prism, (c) said controller determining the relation between the time period of forming said conductive polymer film and the thickness of said conductive polymer film, from the relation between the change of absorbance with time obtained from said absorption spectrum and the thickness of said conductive polymer film, at plural current levels, and (d) said controller determining the relation between current and the film-forming speed in a short time interval from the relation between the film-forming time and the thickness at each current level, and storing it, and (e) said controller controlling the current based on said relation between current and the film-forming speed, such that the speed of forming said conductive polymer film is constant.