Microparticles and a system and method for the synthesis of microparticles

Patent metadata

Field	Value
Publication number	US-10005677-B2
Application number	US-201314404575-A
Country	US
Kind code	B2
Filing date	May 31, 2013
Priority date	May 31, 2012
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

There is provided a method of producing microparticles using an emulsion based synthesis route including: Providing a first fluid phase and a second fluid phase, wherein the first fluid phase is a continuous phase and the second fluid phase is a dispersed phase comprising a dispersed material, wherein the continuous phase is immiscible with the dispersed phase; Mixing the first continuous phase and the second dispersed phase in the presence of a surfactant in a shear device to form an emulsion of droplets of controllable size and having a narrow drop size distribution; Drying the emulsion to form microparticles of controllable size and having narrow size distribution, and wherein the microparticles may comprise spherical, crumpled, dimpled, porous or hollow microparticles morphology. Also provided is a system including shear device and drying arrangement. Also provided are micro particles of controllable size and morphology formed by the method.

First claim

The invention claimed is:

1. A method of producing microparticles using an emulsion based synthesis route, the method comprising:
(i) providing a first fluid phase and a second fluid phase, wherein the first fluid phase is a continuous phase and the second fluid phase is a dispersed phase comprising a dispersed material, wherein the continuous phase is immiscible with the dispersed phase;
(ii) providing a shear device having a first inlet for the first continuous phase and a separate second inlet for the second dispersed phase, the shear device having a rotor configured to revolve inside a stationary stator and an annular gap between the rotor and stator in which emulsification occurs;
(iii) mixing the first continuous phase and the second dispersed phase in the presence of a surfactant in the shear device to form an emulsion of droplets of controllable size and uniformity of droplet size distribution, wherein the mixing step comprises an emulsifying step where the second dispersed phase is emulsified into the first continuous fluid phase in the shear device;
(iv) controlling a volume fraction of the second dispersed phase during the mixing step by controlling the flow rate of the first continuous phase at the first inlet and the second dispersed phase at the second inlet; and
(v) drying the emulsion to form microparticles of controllable size and uniformity of particle size distribution, and wherein the microparticles may comprise spherical, crumpled, dimpled, porous or hollow microparticles morphology.

2. The method of claim 1 wherein the droplets are of less than 50 micron diameter and the microparticles formed are of less than 15 micron diameter.

3. The method of claim 1 , wherein the microparticles formed have a size distribution having a % CV diameter of the order of 25% CV or less.

4. The method of claim 1 further comprising
controlling microparticle morphology to provide the microparticles of spherical, crumpled, dimpled, porous or hollow morphology.

5. The method of claim 1 , wherein droplet size is less than 20 microns.

6. The method of claim 1 , wherein microparticle size is in the range of 200 nm-1 micron.

7. The method of claim 1 wherein the dispersed material comprises nanoparticles.

8. The method of claim 1 wherein the dispersed material comprises superparamagnetic nanoparticles.

9. The method of claim 7 wherein the nanoparticles are metal oxide nanoparticles.

10. The method of claim 8 further comprising controlling magnetization of the microparticles.

11. The method of claim 10 wherein the magnetization of the microparticles is controlled by controlling the concentration of iron oxide Fe 2 O 3 and/or Fe 3 O 4 nanoparticles in the dispersed phase in the range of 0.1-200 mg/mL.

12. The method of claim 10 wherein the magnetization of the microparticles is controllable substantially in the range of 20-110 emU/g.

13. The method of claim 1 further comprising controlling the shear device to control droplet size and uniformity of size distribution and controlling selection of continuous and dispersed phases.

14. The method of claim 1 further comprising controlling: the shear rate and/or dispersed phase volume fraction and/or continuous phase viscosity and/or surfactant concentration and/or the viscosity ratio between phases, and/or the dispersed phase viscosity, to control microparticle size and uniformity of the size distribution of the microparticles.

15. A shear mixing device for mixing a first fluid phase and a second fluid phase, the device comprising:
first and second inlet ports for the first fluid phase and the second fluid phase respectively, the first and second inlet ports being configured for connection to continuous and dispersed phase reservoirs;
a rotor configured to rotate inside a stationary stator at a rate of rotation controllable substantially up to 2000 rpm, the rotor and the stationary stator being arranged such that a gap on the order of 100 microns is provided there between and such that in use as the rotor rotates emulsification of the dispersed phase into the continuous phase occurs inside the shear device in said gap to form an emulsion comprising emulsion droplets, wherein the radius of the rotor and gap size between the rotor and the stationary stator are optimized to minimize emulsion droplet size distribution;
flow rate control means for controlling the flow rate of the continuous phase and the flow rate of the dispersed phase into the shear device, and shear control means for controlling the shear rate and/or rotation of the rotor; and
control means for controlling a volume fraction of the dispersed phase by controlling the relative flow rates of the continuous phase and the dispersed phase into the shear device.

Assignees

• Univ College Dublin Nat Univ Ireland Dublin

Inventors

• Lee Gil
• Platt Mark
• O'Mahony James

Classifications

• B01J13/043

  Drying and spraying · CPC title

• H01F1/0054

  Coated nanoparticles, e.g. nanoparticles coated with organic surfactant · CPC title

• C01P2006/42

  Magnetic properties · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• B01J13/125

  by evaporation of the solvent (apparatus therefor B01J13/043) · CPC title