Stable Iron Oxide Nanoparticles and Method of Production
AssigneeThe Florida State University Research Foundation, Inc.
InventorsJoseph B. Schlenoff, Zaki G. Estephan
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Abstract
A method of preparing a dispersion of stabilized iron oxide nanoparticles that comprise cores and coatings on the cores, which comprise zwitterionic functional groups chemically bound to the cores, using a single solution that comprises dissolved iron ions and a zwitterion silane and/or a hydrolyzed product of the zwitterion silane.
Claims25
A method of preparing a dispersion of stabilized iron oxide nanoparticles that comprise cores, which comprise at least one oxide of iron, and coatings on the cores, which comprise zwitterionic functional groups chemically bound to the cores, the method comprising precipitating at least one oxide of iron from a solution that comprises:
- (a) dissolved ions comprising iron;
- (b) a zwitterion silane, a hydrolyzed product of the zwitterion silane, or a combination thereof, wherein the zwitterion silane comprises a zwitterionic functional group;
- and
- (c) a solvent;
- to form the cores and the coatings and thereby the dispersion of stabilized iron oxide nanoparticles.
A method of preparing a dispersion of stabilized iron oxide nanoparticles that comprise cores, which comprise at least one oxide of iron, and coatings on the cores, which comprise zwitterionic functional groups chemically bound to the cores, the method comprising adjusting the pH of a solution that comprises:
- (a) dissolved iron ions selected from the group consisting of Fe+2, Fe+3, and combinations thereof;
- (b) a zwitterion alkoxysilane, a hydrolyzed product of the zwitterion alkoxysilane, or a combination thereof, wherein the zwitterion alkoxysilane comprises a zwitterionic functional group;
- (c) a solvent that comprises water;
- and
- (d) a molar ratio of iron ions to zwitterion alkoxysilane that is between 0.2 and 5;
- to precipitate the at least one oxide or iron from the solution and form the cores and the coatings and thereby the dispersion of stabilized iron oxide nanoparticles;
- wherein the stabilized iron oxide nanoparticles have an average size that is less than about 10 nm and the coatings have an average thickness that is less than about 5 nm;
- wherein the at least one oxide of iron is selected from the group consisting of Fe2O3, Fe3O4, and combinations thereof;
- wherein the zwitterionic functional groups are chemically bound to the cores via silane groups having the formula
- wherein R6, R7 and R8 are alkyl groups of the formula —CrH2r+1 wherein r is from 1 to about 18 and Z is a zwitterion group having the formula
- wherein m, n, p, q are 1 to about 18 and R5=SO3−, PO4−, or COO−.
Dependencies are inferred from the claim text.