Electrochemical attachment of phosphonic acids to metallic substrates and osteoconductive medical devices containing same
A method of preparing a modified-metal surface by attaching a phosphorous-based acid to a surface of a metal: preparing a solution of the phosphorous-based acid in a protic solvent; immersing a strip of a metal work piece into the solution of the phosphorous-based acid, immersing a strip of a reference metal into the solution of the phosphorous-based acid, supplying a voltage for a duration of time, removing the metal work piece, cleaning the metal work piece, and drying the cleaned metal work piece under an inert atmosphere to obtain a modified metal work piece.
1. A method comprising:
preparing a solution of a phosphorous-based acid in a solvent, wherein the solvent is selected from the group consisting of n-butanol, isopropanol, ethanol, methanol, formic acid, acetic acid, tetrahydrofuran (THF), dimethylformamide (DMF) and ionic liquids and the phosphorous-based acid is a phosphonic acid having a formula: (OH) 2 P(O)(R),
wherein R is an alkyl group having between 4 and 25 atoms;
immersing at least a portion of a metal work piece into the solution of the phosphorous-based acid, wherein the metal is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Al, and alloys thereof or stainless steel;
immersing at least a portion of a reference metal into the solution of the phosphorous-based acid;
supplying a voltage between the metal work piece and the reference metal for a duration of time;
removing the metal work piece from the solution of the phosphorus-based acid;
cleaning the metal work piece; and
drying the cleaned metal work piece to obtain a surface modified metal work piece.
2. The method according to claim 1 , wherein the phosphonic acid is selected from the group consisting of octadecylphosphonic acid, decaphosphonic acid, and dodecaphosphonic acid.
3. The method according to claim 1 , wherein the metal is selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Al, and alloys thereof.
4. The method according to claim 3 , wherein the metal is selected from the group consisting of titanium, titanium alloys, aluminum and aluminum alloys.
5. The method according to claim 1 , wherein the metal is stainless steel.
6. The A method comprising:
preparing a solution of a phosphorous-based acid in a solvent, wherein the solvent is selected from the group consisting of n-butanol, isopropanol, ethanol, methanol, formic acid, acetic acid, tetrahydrofuran (THF), demethylformamide (DMF), and ionic liquids and the phosphorus-based acid is a phosphonic acid having a formula: (OH) 2 P(O)(R), wherein R is an alkyl group having between 4 and 25 carbon atoms;
immersing at least a portion of a metal work piece into the solution of the phosphorous-based acid;
immersing at least a portion of a reference metal into the solution of the phosphorous-based acid;
supplying a voltage between the metal work piece and the reference metal for a duration of time, wherein the metal work piece comprises an anode;
removing the metal work piece from the solution of the phosphorus-based acid;
cleaning the metal work piece; and drying the cleaned metal work piece to obtain a surface modified metal work piece.
7. The method according to claim 1 , wherein the concentration of the solution is from about 1% to about 10% solution by weight.
8. The method according to claim 1 , wherein the voltage applied ranges from about 1 V to about 300 V.
9. The method according to claim 1 , wherein the voltage applied ranges from about 1 V to about 100 V.
10. The method according to claim 1 , wherein the duration of time is from about 1 second to about 5 minutes.
11. The method according to claim 1 , wherein drying the cleaned metal work piece is carried out in an inert atmosphere or dry air.
12. The method according to claim 1 , wherein a coefficient of friction of the modified-metal surface is up to 99% lower than a coefficient of friction of an untreated metal surface.
13. The method according to claim 12 , wherein the coefficient of friction of the modified-metal surface is about 34% to about 59% lower than a coefficient of friction of an untreated metal surface.
14. The method according to claim 1 , wherein a static coefficient of friction of the modified-metal surface is up to 99% lower than a static coefficient of friction of an untreated metal surface.
15. The method according to claim 14 , wherein the static coefficient of friction of the modified-metal surface is about 34% to about 46% lower than a static coefficient of friction of an untreated metal surface.
16. The method according to claim 1 , wherein a dynamic coefficient of friction of the modified-metal surface is up to 99% lower than a dynamic coefficient of friction of an untreated metal surface.
17. The method according to claim 16 , wherein the dynamic coefficient of friction of the modified-metal surface is about 50% to about 59% lower than a dynamic coefficient of friction of an untreated metal surface.
18. The method according to claim 6 , wherein R further comprises a terminal group X, the phosphonic acid comprising a formula: (OH) 2 P(O)(RX), wherein R is an alkyl group having between 4 and 25 carbon atoms, and wherein X is selected from the group consisting of a substituted or unsubstituted hydroxyl group, a substituted or unsubstituted amine group, and a substituted or unsubstituted ester group.
19. The method according to claim 18 , wherein X is a substituted or unsubstituted methacrylate group.
20. The method according to claim 1 , wherein R further comprises a terminal group X, the phosphonic acid comprising a formula: (OH) 2 P(O)(RX), wherein R is an alkyl group having between 4 and 25 carbon atoms, and wherein X is selected from the group consisting of a substituted or unsubstituted hydroxyl group, a substituted or unsubstituted amine group, and a substituted or unsubstituted ester group.
21. The method according to claim 20 , wherein X is a substituted or unsubstituted methacrylate group.