Method and apparatus for electrochemical surface treatment of discontinuous conductive materials

Abstract

Disclosed is an electrolytic cell and method for use of such a cell for surface treatment of discontinuous materials. The electrolytic cell includes a porous electrically conductive mat operably connected to a power supply and a porous structure that is configured to keep a discontinuous material in an electrolyte solution in contact with the porous electrically conductive mat while a surface treatment is being applied.

What is claimed is: 
     
         1 . A method for the surface modification of discontinuous conductive materials, comprising the steps of:
 introducing a plurality of discontinuous materials to an electrolyte solution within an electrolytic cell;   keeping the plurality of discontinuous materials in contact with a porous electrically conductive mat using a mechanical force, fluid flow, or gravity, the porous electrically conductive mat being operably connected to a current supply; and   treating the plurality of discontinuous materials by applying current to the electrolytic cell; and   removing or allowing the treated discontinuous materials to be removed from the porous electrically conductive mat.   
     
     
         2 . The method according to  claim 1 , wherein the electrolyte solution comprises a water-soluble salt, a metal salt, or a combination thereof. 
     
     
         3 . The method according to  claim 1 , wherein a voltage applied by the current supply is between about −21 V and 21 V. 
     
     
         4 . The method according to  claim 1 , wherein the temperature of the electrolyte solution is between about 3° C. and about 100° C. 
     
     
         5 . The method according to  claim 1 , further comprising analyzing at least one of the plurality of discontinuous materials to determine surface content of heteroatoms. 
     
     
         6 . The method according to  claim 1 , wherein the current is configured to reverse polarity at least once during treatment. 
     
     
         7 . The method according to  claim 1 , wherein the discontinuous materials comprise a carbon fiber. 
     
     
         8 . The method according to  claim 1 , wherein the porous electrically conductive mat is carbon felt or platinum mesh. 
     
     
         9 . The method according to  claim 1 , wherein the mechanical force is applied with a porous structure or a screw conveyor. 
     
     
         10 . The method according to  claim 9 , wherein the porous structure is a platinum or polytetrafluoroethylene (PTFE) mesh. 
     
     
         11 . The method according to  claim 9 , wherein the porous structure is operably connected to a plunger and is configured to be raised to allow the plurality of discontinuous materials to be added to or removed from the electrolytic cell, and lowered to push the plurality of discontinuous materials onto the porous electrically conductive mat. 
     
     
         12 . An electrolytic cell, comprising:
 a power supply configured to provide a current;   a porous electrically conductive mat operably connected to the power supply, the porous electrically conductive mat configured to allow liquid, gas, or combination thereof to leave an outer surface of a discontinuous material in contact with the porous electrically conductive mat, the discontinuous material being within an electrolyte solution; and   a porous structure configured to keep the discontinuous material in contact with the porous electrically conductive mat while a surface treatment is being applied.   
     
     
         13 . The electrolytic cell according to  claim 12 , wherein the electrolyte solution comprises a water-soluble salt, a metal salt, or a combination thereof. 
     
     
         14 . The electrolytic cell according to  claim 12 , wherein the temperature of the electrolyte solution is between about 3° C. and about 100° C. 
     
     
         15 . The electrolytic cell according to  claim 12 , wherein the polarity of the current is configured to reverse at least once during the surface treatment. 
     
     
         16 . The electrolytic cell according to  claim 12 , wherein the discontinuous material comprises a carbon fiber. 
     
     
         17 . The electrolytic cell according to  claim 12 , wherein the porous electrically conductive mat is carbon felt or platinum mesh. 
     
     
         18 . The electrolytic cell according to  claim 12 , wherein the porous electrically conductive mat is directly connected to the power supply. 
     
     
         19 . The electrolytic cell according to  claim 12 , wherein the porous structure is a platinum or polytetrafluoroethylene (PTFE) mesh. 
     
     
         20 . The electrolytic cell according to  claim 12 , wherein the porous structure is operably connected to a plunger and is configured to be raised to allow a plurality of discontinuous materials to be added to or removed from the electrolytic cell, and lowered to push the plurality of discontinuous materials onto the porous electrically conductive mat.