Potentiostatic preparation of molecular adsorbates for scanning probe microscopy

Abstract

.[.A method of.]. .Iadd.An apparatus and method for .Iaddend.preparing molecular adsorbates for scanning probe microscopy by potentiostatic methods. Negatively charged molecules are deposited upon and held to a substrate with an electrochemical cell having a gold substrate, a platinum wire counter electrode and a silver wire reference electrode. The polymer to be observed is dissolved into a buffer solution which is non-reactive with the substrate which is gold (111).

Accordingly, what is claimed is: 
     
       1. A method of preparing molecular adsorbates for scanning probe microscopy comprising: loading a substrate into a cell; placing the cell on a scanning probe microscope; placing a clean reference electrode in said cell; placing a clean counter electrode in said cell in spaced relationship to said reference electrode; dissolving a polymer containing negatively charged molecules into a buffer solution that is inert relative to said substrate; filling said cell with said polymer .[.contained.]. .Iadd.containing .Iaddend.buffer solution; activating said reference electrode and said counter electrode and applying a potential to said substrate to deposit and secure said polymer onto said substrate for examination by said microscope. 
     
     
       2. A method according to claim 1 in which said substrate is gold (111). 
     
     
       3. A method according to claim 1 in which said reference electrode is silver wire. 
     
     
       4. A method according to claim 1 in which said counter electrode is platinum wire. 
     
     
       5. A method according to claim 1 in which said buffer solution is NaH 2  PO 4  at a pH of 6. 
     
     
       6. A method according to claim 3 in which said electrodes are activated to a voltage of from about -1.2 up to about .Iadd.+ .Iaddend.1.3. 
     
     
       7. A method according to claim 5 in which said electrodes are activated to a voltage of from about -1.2 up to about .Iadd.+ .Iaddend.1.3. 
     
     
       8. A method according to claim 2 in which said reference electrode is silver wire. 
     
     
       9. A method according to claim 8 in which said counter electrode is platinum wire. 
     
     
       10. A method according to claim 9 in which said buffer solution is NaH 2  PO 4  at a pH of 6. 
     
     
       11. A method according to claim 10 in which said electrodes are activated to a voltage of from about -1.2 up to about .Iadd.+ .Iaddend.1.3. .Iadd. 
     
     
       12.  A method of preparing molecular adsorbates for scanning probe microscopy comprising: loading a substrate into a cell;   placing the cell on a scanning probe microscope;   placing a clean reference electrode in said cell;   placing a clean counter electrode in said cell in spaced relationship to said reference electrode;   dissolving a polymer containing charged molecules into a buffer solution that is inert relative to said substrate;   filling said cell with said polymer containing buffer solution;   activating said reference electrode and said counter electrode; and   applying a potential between said substrate and said counter electrode to deposit and secure said polymer onto said substrate for examination by said microscope..Iaddend..Iadd.13. A method according to claim 12 in which said substrate comprises gold..Iaddend..Iadd.14. A method according to claim 12 in which said reference electrode is silver wire..Iaddend..Iadd.15. A method according to claim 12 in which said   
     
     
        counter electrode is platinum wire..Iaddend..Iadd.16.  A method according to claim 12 in which said buffer solution is NaH 2  PO 4  at a pH of 6. .Iaddend..Iadd.17. A method according to claim 13 in which said substrate is activated to a voltage in a range of about -1.2 volts up to about +1.3 volts with respect to said reference electrode by application of a suitable voltage to said counter electrode..Iaddend..Iadd.18. A method according to claim 14 in which said substrate is activated to a voltage in a range of about -1.2 volts up to about +1.3 volts with respect to said reference electrode by application of a suitable voltage to said counter electrode..Iaddend..Iadd.19. A method according to claim 15 in which said substrate is activated to a voltage in a range of about -1.2 volts UP to about +1.3 volts with respect to said reference electrode by application of a suitable voltage to said counter electrode..Iaddend..Iadd.20. A method according to claim 16 in which said substrate is activated to a voltage in a range of about -1.2 volts up to about +1.3 volts with respect to said reference electrode by application of a suitable voltage to said counter electrode..Iaddend..Iadd.21. A method according to claim 13 in which said reference electrode is silver wire..Iaddend..Iadd.22. A method according to claim 15 in which said reference electrode is silver wire..Iaddend..Iadd.23. A method according to claim 13 in which said counter electrode is platinum wire..Iaddend..Iadd.24. A method according to claim 16 in which said counter electrode is platinum wire..Iaddend..Iadd.25. A method according to claim 23 in which said buffer solution is NaH 2  PO 4  at a pH of 6. .Iadd.26. A method according to claim 25 in which said substrate is activated to a voltage in a range of about -1.2 volts up to about +1.3 volts with respect to said reference electrode by application of a suitable voltage to said counter electrode..Iaddend..Iadd.27. An electrochemical fluid cell and substrate assembly for use in studying molecular adsorbates with a scanning probe microscope, said cell comprising: an electrically conductive substrate;   an electrically insulating cell wall having an inner boundary defining a fluid container open at its top, said fluid container having a bottom boundary defined by said substrate;   said substrate having a portion extending under and beyond said inner boundary;   a reference electrode extending from beyond said fluid container into said fluid container through said top;   a counter electrode extending from beyond said fluid container into said fluid container through said top and maintained in spaced relationship to said reference electrode;   a voltage potential capable of being applied to said substrate by connecting said voltage potential to said electrically conductive substrate at said portion extending under and beyond said inner boundary..Iaddend..Iadd.28. An electrochemical fluid cell and substrate assembly according to claim 27 wherein said substrate comprises gold..Iaddend..Iadd.29. An electrochemical fluid cell and substrate assembly according to claim 27 wherein said reference electrode is silver wire..Iaddend..Iadd.30. An electrochemical fluid cell and substrate assembly according to claim 27 wherein said counter electrode is platinum   
     
     
        wire..Iaddend..Iadd.31.  An electrochemical fluid cell and substrate assembly according to claim 28 wherein said reference electrode is silver wire..Iaddend..Iadd.32. An electrochemical fluid cell and substrate assembly according to claim 28 wherein said counter electrode is platinum wire..Iaddend..Iadd.33. An electrochemical fluid cell and substrate assembly according to claim 28 wherein said reference electrode is silver wire and said counter electrode is platinum wire..Iaddend..Iadd.34. An electrochemical fluid cell and substrate assembly for use in studying molecular adsorbates with a scanning probe microscope, said cell comprising: an electrically conductive substrate;   an electrically insulating cell wall having an inner boundary defining a fluid container open at its top, said fluid container having a bottom boundary defined by said substrate;   said substrate in electrical contact with a conductor having a portion extending under and beyond said inner boundary;   a reference electrode extending from beyond said fluid container into said fluid container through said top;   a counter electrode extending from beyond said fluid container into said fluid container through said top and maintained in spaced relationship to said reference electrode;   a voltage potential capable of being applied to said substrate by connecting said voltage potential to said electrically conductive substrate at said portion of said conductor extending under and beyond said inner boundary..Iaddend..Iadd.35. An electrochemical fluid cell and substrate assembly according to claim 34 wherein said substrate comprises gold..Iaddend..Iadd.36. An electrochemical fluid cell and substrate assembly according to claim 34 wherein said reference electrode is silver wire..Iaddend..Iadd.37. An electrochemical fluid cell and substrate assembly according to claim 34 wherein said counter electrode is platinum wire..Iaddend..Iadd.38. An electrochemical fluid cell and substrate assembly according to claim 35 wherein said reference electrode is silver wire..Iaddend..Iadd.39. An electrochemical fluid cell and substrate assembly according to claim 35 wherein said counter electrode is platinum wire..Iaddend..Iadd.40. An electrochemical fluid cell and substrate assembly according to claim 35 wherein said reference electrode is silver wire and said counter electrode is platinum wire. .Iaddend.