# US 10,319,502 B2 · Polymer-encapsulated magnetic nanoparticles

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- Number: US 10,319,502 B2
- Document ID: US10319502B2
- Status: Granted
- Kind: B2
- Application number: 15/520,581
- Filed: 2015-10-23
- Published: 2018-05-31
- Granted: 2019-06-11
- Earliest claimed: 2014-10-23
- Assignees: Corning Incorporated
- Applicants: Corning Incorporated
- Inventors: Ann MeeJin Ferrie; Yan Jin; Lingyan Wang; Yue Zhou
- Web page: https://patentgrep.com/patent/US10319502B2

## CPC

- H01F 1/0054: {Coated nanoparticles, e.g. nanoparticles coated with organic surfactant}
- B22F 1/054: Nanosized particles
- B22F 1/056: {Submicron particles having a size above 100 nm up to 300 nm}
- B22F 1/102: Metallic powder coated with organic material
- B22F 9/18: with reduction of metal compounds
- B82Y 40/00: Manufacture or treatment of nanostructures
- C12N 15/1013: {by using magnetic beads}
- H01F 1/12: of soft-magnetic materials
- H01F 1/344: {Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4}
- H01F 41/02: for manufacturing cores, coils, or magnets (H01F41/14 takes precedence; for dynamo-electric machines H02K15/00)
- H01F 1/20: in the form of particles, e.g. powder (H01F1/147 takes precedence)
- H01F 1/36: in the form of particles {(H01F1/346, H01F1/348 and H01F1/38 take precedence)}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C12N: MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA (microbiological testing media C12Q1/00)

## Abstract

Magnetic particles (100) have a particle size (134) of 500 nm or less and include a core (110) and a polymer coating (120) that surrounds and encapsulates the core (110). The core (110) includes a metal, metal alloy, or metal oxide of at least one metal such as B, Mg, Al, Mn, Co, Ni, Cu, Fe Sm, Yb, Dy, Gd or Er and Nb. The magnetic core (100) is a polycrystalline particle and is a superspin glass magnetic material, having a coercivity greater than zero and a magnetic remenance greater than zero at room temperature. Above room temperature and at low field, the magnetic moment of these superspin glass magnetic materials increases with temperature. An in situ hydrolysis/precipitation method from precursor metal salts is used to form the polymer-encapsulated magnetic particles (100).

## Claims

### Claim 1

Magnetic particles comprising:
a magnetic core and a polymer coating;
wherein the magnetic core comprises a metal, metal alloy, or metal oxide of at least one metal selected from the group consisting of B, Mg, Al, Mn, Co, Ni, Cu, Fe, Nb, Sm, La, Yb, Dy, Gd or Er;
wherein the magnetic core comprises polycrystalline particles which are superparamagnetic and which are coalesced to form a superspin glass magnetic core;
wherein the polymer coating surrounds the magnetic core;
and wherein the magnetic particles exhibit coercivity greater than zero and less than 300 Oe and magnetic remanence between 3 and 10 emu/g at room temperature;
wherein the magnetic particle has a particle size of 500 nm or less.

### Claim 2 (depends on 1)

The magnetic particles of claim 1 wherein the polycrystalline particles of the magnetic core are the same crystalline phase.

### Claim 3 (depends on 1)

The magnetic particles of claim 1, wherein the particles comprise a saturation magnetization greater than 50 and less than 100 emu/g at room temperature.

### Claim 4 (depends on 1)

The magnetic particles of claim 1, wherein the polycrystalline particles which have coalesced to form a superspin glass magnetic core is a soft a soft magnetic material.

### Claim 5 (depends on 1)

The magnetic particles of claim 1, wherein the coercivity is between 30 and 150 Oe.

### Claim 6 (depends on 1)

The magnetic particles of claim 1, wherein the polymer coating is selected from the group consisting of poly(ethyl methacrylate), poly(ethylene-alt-maleic anhydride), poly(methyl methacrylate), polyethyl imine, poly(methacrylic acid), poly(4-styrene sulfonic acid-co-maleic acid), polyacrylic acid, polyvinyl alcohol, poly thiol, and poly mercapto acid or a combination.

### Claim 7 (depends on 1)

The magnetic particles of claim 1, wherein the core comprises at least 60 wt. % of the particle.

### Claim 8 (depends on 1)

The magnetic particles of claim 1, wherein the magnetic particle has a diameter of 10 to 250 nm.

### Claim 9 (depends on 1)

The magnetic particles of claim 1, wherein the polymer coating has an average thickness of between 10 nm to 250 nm.

### Claim 10 (depends on 1)

The magnetic particles of claim 1 further comprising a surface functional group selected from the group consisting of carboxylic acid/carboxylate, amino/imine, methyl, methylene, thiol, anhydride, phosphoric acid, sulfuric acid/sulfonate, sulfonamide, and phosphatide.

### Claim 11 (depends on 1)

The magnetic particles of claim 1, wherein the magnetic core comprises Fe3O4.