Claims
- 1. A stabilized composition comprising magnetic particles and a block copolymer stabilizer in a polysiloxane medium, wherein the stabilizer comprises at least one block capable of chelating the metal particles, and at least one end block which is compatible with the polysiloxane medium.
- 2. The composition of claim 1, wherein the block copolymer stabilizer comprises at least one block capable of chelating the metal particles linked to at least one polysiloxane endblock compatible with the polysiloxane medium.
- 3. The composition of claim 2, wherein the block copolymer stabilizer comprises one cyano-substituted siloxane block capable of chelating the metal particles linked to at least one polysiloxane endblock compatible with the polysiloxane medium.
- 4. The composition of claim 1, wherein the magnetic particles are chosen from the group consisting of cobalt, nickel, iron, iron oxide, neodymium, samarium and variations and combinations thereof.
- 5. The composition of claim 4, wherein the medium is polydimethylsiloxane.
- 6. The composition of claim 1, wherein the stabilizer is a triblock copolymer.
- 7. The composition of claim 4, wherein the average magnetic particle size is about 2-20 nm in diameter.
- 8. The composition of claim 3, wherein the cyano-containing polysiloxane block is poly(3-cyanopropyl)methylsiloxane.
- 9. The composition of claim 1, wherein the ratio of stabilizer to magnetic particles is from about 1:10 to about 10:1 by weight.
- 10. The composition of claim 1, wherein the stabilizer and magnetic particles constitute about 10% to about 100% of the total volume of the magnetic fluid.
- 11. The composition of claim 1, wherein the magnetic particles are cobalt and the carrier fluid polydimethylsiloxane.
- 12. The composition of claim 2, wherein the block copolymer stabilizer also functions as the carrier fluid.
- 13. The composition of claim 11 or 12, wherein the average particle size is about 17-20 nm in diameter.
- 14. The composition of claim 1, wherein the length of the block capable of chelating the metal particles is from about 1,000 to about 6,000 g/mole and the length of the end block is from about 4,000 to about 18,000 g/mole.
- 15. The composition of claim 3, wherein the length of the block capable of chelating the metal particles is from about 1,500 to about 5,500 g/mole and the length of the end block is from about 5,000 to about 17,000 g/mole.
- 16. The composition of claim 1, wherein the block copolymer stabilizer has the formula:
- 17. The composition of claim 16, wherein at least one R=CH3.
- 18. The composition of claim 16, wherein R′=3-cyanopropyl.
- 19. A method for making poly(dimethylsiloxane-b-cyanopropylmethylsiloxane-b-dimethylsiloxane) triblock copolymer comprising:
a) hydrosilylation of tetramethylcyclotetrasiloxane with allyl cyanide to produce 3-cyanopropylmethylcuclotetrasiloxane; b) deprotonation of diphenylsilanediol using diohenylmethyllithium to produce dilithium diphenylsilanediolate; c) equilibrium polymerization of 3-cyanopropylmethylcyclotetrasiloxane with dilithium diohenylsilanediolate as an initiator to produce lithium silanolate capped polycyanopropylmethylsiloxane macroinitiators; and d) polymerization of hexamethylcyclotrisioxane using the lithium silonate capped polycyanopropylmethylsiloxane macroinitiators to produce poly(dimethylsiloxane-b-cyanopropylmethylsiloxane-b-dimethylsiloxane) triblock copolymers.
- 20. A method for making poly(dimethylsiloxane-b-cyanopropylmethylsiloxane-b-dimethylsiloxane) triblock copolymer comprising:
a) hydrosilylation of tetramethylcyclotetrasiloxane with allyl cyanide to produce 3-cyanopropylmethylcuclotetrasiloxane; b) equilibrium polymerization of 3-cyanopropylmethylcuclotetrasiloxane with lithium hydroxide to produce lithium silanolate capped polycyanopropylmethylsiloxane macroinitiators; and c) polymerization of hexamethylcyclotrisioxane using the lithium silonate capped polycyanopropylmethylsiloxane macroinitiators to produce poly(dimethylsiloxane-b-cyanopropylmethylsiloxane-b-dimethylsiloxane) triblock copolymers.
- 21. A method for treating retinal detachment in an eye comprising:
a) inserting an effective amount of a stabilized composition comprising magnetic particles and a block copolymer stabilizer in a polysiloxane medium, wherein the stabilizer comprises at least one cyano-containing polysiloxane block capable of chelating the metal particles, and at least one end block comprising a polysiloxane which is compatible with the medium; and b) applying a magnetized scleral buckle to said eye.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is continuation-in-part of U.S. patent application Ser. No. 09/075,698 filed May, 11,1998, which is based on U.S. Provisional Application Serial No. 60/046,171, filed May 12,1997, incorporated herein by reference in full.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09075698 |
May 1998 |
US |
Child |
09342885 |
Jun 1999 |
US |