Permanently linked, rigid, magnetic chains
One aspect of the present invention relates to a permanently linked, rigid, magnetic chain of particles prepared by sol-gel methods. A second aspect of the present invention relates to a method of preparing a permanently linked, rigid, magnetic chain of particles comprising: coating a core material with one or more polyelectrolyte layers resulting in a coated particle; further coating the coated particle with a layer of magnetic nanoparticles resulting in a magnetic particle; coating the magnetic particle with a layer of a polycationic polyelectrolyte resulting in a coated magnetic particle; and applying a magnetic field to the coated magnetic particle in the presence of a metal oxide or metal oxide precursor capable of undergoing hydrolysis.
1. A permanently linked, rigid, magnetic chain, comprising a plurality of colloidal-sized particles, wherein:
(a) each of said particles comprises a first layer, wherein said first layer comprises a magnetic metal oxide;
(b) each of said particles optionally comprises a core material; and
(c) said particles are linked together with a second layer, wherein said second layer comprises a homogeneous inorganic oxide.
2. The magnetic chain of claim 1 , wherein said core material is present and is a bead.
3. The magnetic chain of claim 1 , wherein said core material is present and is a polymeric bead.
4. The magnetic chain of claim 1 , wherein said core material is present and is a polystyrene bead.
5. The magnetic chain of claim 1 , wherein said core material is present and is a polymeric bead coated with one or more layers of a polyelectrolyte.
6. The magnetic chain of claim 1 , wherein said core material is present and is a polystyrene bead coated with one or more layers of a polyelectrolyte.
7. The magnetic chain of claim 1 , wherein each of said particles comprises a polystyrene bead coated with three layers of a polyelectrolyte in the order: polycationic polyelectrolyte, polyanionic polyelectrolyte, polycationic polyelectrolyte.
8. The magnetic chain of claim 7 , wherein the polycationic polyelectrolyte is poly(diallyldimethyl) ammonium chloride and the polyanionic polyelectrolyte is polystyrene sulfonate.
9. The magnetic chain of claim 1 , wherein the magnetic metal oxide comprises an iron oxide.
10. The magnetic chain of claim 7 , wherein the magnetic metal oxide is an iron oxide.
11. The magnetic chain of claim 9 , wherein the iron oxide is Fe 2 O 3 .
12. The magnetic chain of claim 10 , wherein the iron oxide is Fe 2 O 3 .
13. The magnetic chain of claim 1 , wherein the particles further comprise an outer layer of a polycationic polyelectrolyte.
14. The magnetic chain of claim 10 , wherein the particles further comprise an outer layer of a polycationic polyelectrolyte.
15. The magnetic chain of any one of claims 1 - 8 or 9 - 14 , wherein the homogenous inorganic oxide is TiO 2 .
16. The magnetic chain of claim 1 , wherein said core material is absent.
17. A composition comprising the magnetic chain of any one of claims 1 - 8 , 9 - 14 , 15 , or 16 .