Initiated chemical vapor deposition of vinyl polymers for the encapsulation of particles

Patent metadata

Field	Value
Publication number	US-9492805-B2
Application number	US-58968306-A
Country	US
Kind code	B2
Filing date	Oct 30, 2006
Priority date	Nov 1, 2005
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

Described herein are all-dry encapsulation methods that enable well-defined polymers to be applied around particles. One aspect of the invention relates to a method of coating a particle, comprising the steps of: placing said particle in a vessel at a pressure; rotating said vessel at a rotating speed for a period of time; mixing together a first gaseous monomer at a first flow rate, and a gaseous initiator at a second flow rate, thereby forming a mixture; introducing said mixture into said vessel via a vapor feedline; heating said mixture, thereby forming a reactive mixture; contacting said particle with said reactive mixture; thereby forming a polymer coating on said particle. The methods may be modified forms of initiated chemical vapor deposition using a thermally-initiated radical polymerization to create conformal coatings around individual particles while avoiding agglomeration. Particle surfaces may be coated with a range of functional groups.

First claim

We claim:

1. A method, comprising the steps of:
placing a plurality of individual particles in a vessel at a pressure; wherein said vessel comprises a vapor feedline for delivering vapors into said vessel through exit holes, and a filament in proximity to said exit holes; the individual particles consist of soda glass, silica, carbon, or a drug; and the diameters of said individual particles are about 5 μm to about 35 μm;
contacting said vessel with a water bath at a first temperature, wherein said first temperature is between about 0° C. and about 100° C.;
rotating said vessel at a rotating speed for a period of time;
mixing together a first gaseous monomer at a first flow rate, and a gaseous initiator at a second flow rate, thereby forming a mixture;
introducing said mixture into said vessel via said vapor feedline which comprises said filament at a second temperature, wherein said second temperature is between about 150° C. and 350° C.;
heating said mixture with said filament, thereby forming a reactive mixture;
contacting said plurality of individual particles with said reactive mixture; thereby forming a plurality of individual coated particles, wherein each individual coated particle consists of a substantially uniform polymer coating encapsulating one individual particle; the thickness of said substantially uniform polymer coating is about 3 μm to about 12 μm; each individual particle is non-agglomerated; and the plurality of individual coated particles is non-agglomerated.

2. The method of claim 1 , wherein the gaseous initiator is selected from the group consisting of compounds of formula I:
A-X—B  I

wherein,
A is hydrogen, alkyl, cycloalkyl, aryl, heteroaryl, aralkyl or heteroaralkyl;
X is —O—O—or —N═N—; and
B is hydrogen, alkyl, cycloalkyl, aryl, heteroaryl, aralkyl or heteroaralkyl.

3. The method of claim 1 , wherein the gaseous initiator is selected from the group consisting of hydrogen peroxide, alkyl peroxides, aryl peroxides, hydroperoxides, halogens and azo compounds.

4. The method of claim 1 , wherein said first gaseous monomer is selected from the group consisting of

R is selected from the group consisting of hydrogen and alkyl;
R 1 is selected from the group consisting of hydrogen, alkyl, aralkyl, heteroaralkyl, and carboxyl;
R 2 is independently selected from the group consisting of hydrogen, alkyl, bromine, chlorine, hydroxyl, alkoxy, aryloxy, carboxyl, amino, acylamino, amido, carbamoyl, sulfhydryl, sulfonate, and sulfoxido;
X is selected from the group consisting of hydrogen, alkyl, cycloalkyl, heteocycloalkyl, aryl, heteroaryl, aralkyl, heteoaralkyl, and —(CH 2 ) n Y;
Y is selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, heteoaralkyl, nitro, halo, hydroxyl, alkoxy, aryloxy, carboxyl, heteroaryloxy, amino, acylamino, amido, carbamoyl, sulfhydryl, sulfonate, and sulfoxido;
and
n is 1-10 inclusive.

5. The method of claim 4 , wherein R is methyl.

6. The method of claim 4 , wherein X is hydrogen or —(CH 2 ) n Y.

7. The method of claim 4 , wherein Y is alkyl, cycloalkyl, heterocycloalkyl, aryl, nitro, halo, hydroxyl, alkoxy, aryloxy, amino, acylamino, amido, or carbamoyl.

8. The method of claim 4 , where n is 3-8 inclusive.

9. The method of claim 4 , wherein said first gaseous monomer is selected from the group consisting of

R is selected from the group consisting of hydrogen and methyl;
R 2 is independently selected from the group consisting of hydrogen, methyl, bromine and chlorine;
X is hydrogen or —(CH 2 ) 2 Y;
Y is selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, heteoaralkyl, nitro, halo, hydroxyl, alkoxy, aryloxy, carboxyl, heteroaryloxy, amino, acylamino, amido, carbamoyl, sulfhydryl, sulfonate, and sulfoxido;
and
n is 1-10 inclusive.

10. The method of claim 9 , wherein R is methyl.

11. The method of claim 9 , wherein Y is hydrogen or heterocycloalkyl.

12. The method of claim 9 , wherein Y is hydrogen.

13. The method of claim 9 , wherein Y is an oxirane.

14. The method of claim 9 , wherein n is 3-8 inclusive.

15. The method of claim 1 , wherein said individual particles consist of soda glass.

16. The method of claim 1 , wherein the average particle size of the plurality of individual coated particles is not more than 5% larger than the average particle size of the plurality of individual particles, apart from the particle size increase attributable to the coating itself.

17. The method of claim 1 , wherein said individual particles consist of silica.

18. The method of claim 1 , wherein said individual particles consist of carbon.

19. The method of claim 1 , wherein said individual particles consist of carbon in the form of graphite, a fullerene, a nanotube, or diamond.

20. The method of claim 1 , wherein said individual particles consist of a drug.

Assignees

• Gleason Karen K
• Lau Kenneth K S
• Massachusetts Inst Technology

Inventors

• Gleason Karen K
• Lau Kenneth K S

Classifications

• B01J13/04 Primary

  by physical processes, e.g. drying, spraying · CPC title

• B01J13/14

  Polymerisation; cross-linking · CPC title

• A61K9/5026

  obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates · CPC title

• C23C16/4417

  Methods specially adapted for coating powder · CPC title

• C23C16/452

  by activating reactive gas streams before {their} introduction into the reaction chamber, e.g. by {ionisation} or addition of reactive species · CPC title