System and method for enhanced electrostatic deposition and surface coatings

• US 8,795,762 B2
• Filed: 03/26/2010
• Issued: 08/05/2014
• Est. Priority Date: 03/26/2010
• Status: Active Grant

• Current Assignee: Micell Medtech Incorporated
• Original Assignee: Battelle Memorial Institute
• Inventors: Fulton, John L., Deverman, George S., Matson, Dean W., Yonker, Clement R., Taylor, C. Douglas, McClain, James B., Crowley, Joseph M.
• Primary Examiner(s): SELLMAN, CACHET I
• Application Number:
  US12/748,134
• Publication Number:
  US 20110238161A1
• Time in Patent Office: 1,593 Days
• Field of Search: None
• US Class Current: 427/2.24
• CPC Class Codes: B05B 5/032 for spraying particulate materials
• CPC Class Codes: B05D 1/025 using gas close to its critical state
• CPC Class Codes: B05D 1/04 involving the use of an electrostatic field B05D1/025 and B05D1/14 take precedence
• CPC Class Codes: B05D 3/0486 Operating the coating or treatment in a controlled atmosphere
• CPC Class Codes: Y10T 428/24372 Particulate matter
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31931 Polyene monomer-containing
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31938 Polymer of monoethylenically unsaturated hydrocarbon

Abstract

This disclosure describes the application of a supplemental corona source to provide surface charge on submicrometer particles to enhance collection efficiency and micro-structural density during electrostatic collection.

Claims

1. A method for forming a coating on a surface of a substrate, comprising:

providing a substrate;

establishing an electric field between said substrate and a counter electrode;

producing coating particles suspended in a gaseous phase of an expanded near-critical or supercritical fluid released from an expansion nozzle having a first average electric potential; and

contacting said coating particles with a stream of charged ions from an auxiliary emitter at a second average electric potential in an inert carrier gas to increase the charge differential between said coating particles and said substrate, wherein said coating particles impact said substrate to form a coating on the surface of the substrate.

2. The method of claim 1, wherein the coating particles have a first velocity upon release of the coating particles from the expansion nozzle that is less than a second velocity of the coating particles when said coating particles impact said substrate.

3. The method of claim 1, wherein attraction of the coating particles to the substrate is increased as compared to attraction of the coating particles to the substrate in a system without the auxiliary emitter.

4. The method of claim 1, wherein the first average electric potential is different than the second average electric potential.

5. The method of claim 1, wherein an absolute value of the first average electric potential is less than an absolute value of the second average electric potential, and wherein a polarity of the charged ions is the same as a polarity of the coating particles.

6. The method of claim 1, wherein said coating particles have a size between about 0.01 micrometers and about 10 micrometers.

7. The method of claim 1, wherein said substrate has a negative polarity and an enhanced charge of said coating particles following the contacting step is a positive charge;

or wherein said substrate has a positive polarity and an enhanced charge of said coating particles following the contacting step is a negative charge.

8. The method of claim 1, wherein the contacting step comprises forming a positive corona or forming a negative corona positioned between the expansion nozzle and said substrate.

9. The method of claim 1, wherein the contacting step comprises forming a positive corona or forming a negative corona positioned between the auxiliary emitter and said substrate.

10. The method of claim 1, wherein the coating has a density on said surface from about 1 volume % to about 60 volume %.

11. The method of claim 1, wherein said coating particles comprises at least one of:

a polymer, a drug, a biosorbable material, a protein, a peptide, or a combination thereof.

12. The method of claim 1, wherein said coating particles comprises at least one of:

polylactic acid (PLA);

poly(lactic-co-glycolic acid) (PLGA);

polycaprolactone (poly(e-caprolactone)) (PCL), polyglycolide (PG) or (PGA), poly-3-hydroxybutyrate;

LPLA poly(l-lactide), DLPLA poly(dl-lactide), PDO poly(dioxolane), PGA-TMC, 85/15 DLPLG p(dl-lactide-co-glycolide), 75/25 DLPL, 65/35 DLPLG, 50/50 DLPLG, TMC poly(trimethylcarbonate), p(CPP;

SA) poly(1,3-bis-p-(carboxyphenoxy)propane-co-sebacic acid) and blends, combinations, homopolymers, condensation polymers, alternating, block, dendritic, crosslinked, or copolymers thereof.

13. The method of claim 1, wherein said coating particles comprise at least one of:

polyester, aliphatic polyester, polyanhydride, polyethylene, polyorthoester, polyphosphazene, polyurethane, polycarbonate urethane, aliphatic polycarbonate, silicone, a silicone containing polymer, polyolefin, polyamide, polycaprolactam, polyamide, polyvinyl alcohol, acrylic polymer, acrylate, polystyrene, epoxy, polyethers, celluiosics, expanded polytetrafluoroethylene, phosphorylcholine, polyethyleneyerphthalate, polymethylmethavrylate, poly(ethylmethacrylate/n-butylmethacrylate), parylene C, polyethylene-co-vinyl acetate, polyalkyl methacrylates, polyalkylene-co-vinyl acetate, polyalkylene, polyalkyl siloxanes, polyhydroxyalkanoate, polyfluoroalkoxyphasphazine, poly(styrene-b-isobutylene-b-styrene), poly-butyl methacrylate, poly-byta-diene, and blends, combinations, homopolymers, condensation polymers, alternating, block, dendritic, crosslinked, or copolymers thereof.

14. The method of claim 1, wherein said coating particles include a drug comprising one or more of:

rapamycin, biolimus (biolimus A9), 40-O-(2-Hydroxyethyl)rapamycin (everolimus), 40-O-Benzyl-rapamycin, 40-O-(4′

-Hydroxymethyl)benzyl-rapamycin, 40-O-[4′

-(1,2-Dihydroxyethyl)]benzyl-rapamycin, 40-O-Allyl-rapamycin, 40-O-[3′

-(2,2-Dimethyl-1,3-dioxolan-4(S)-yl)-prop-2′

-en-1′

-yl]-rapamycin, (2′

;

E,4′

S)-40-O-(4′

,5′

-Dihydroxypent-2′

-en-1′

-yl)-rapamycin, 40-O-(2-Hydroxy)ethoxycar-bonylmethyl-rapamycin, 40-O-(3-Hydroxy)propyl-rapamycin, 40-O-(6-Hydroxy)hexyl-rapamycin, 40-O-[2-(2-Hydroxy)ethoxy]ethyl-rapamycin, 40-O-[(3S)-2,2-Dimethyldioxolan-3-yl]methyl-rapamycin, 40-O-[(2S)-2,3-Dihydroxyprop-1-yl]rapamycin, 40-O-(2-Acetoxy)ethyl-rapamycin, 40-O-(2-Nicotinoyloxy)ethyl-rapamycin, 40-O-[2-(N-Morpholino)acetoxy]ethyl-rapamycin, 40-O-(2-N-Imidazolylacetoxy)ethyl-rapamycin, 40-O-[2-(N-Methyl-N′

-piperazinyl)acetoxy]ethyl-rapamycin, 39-O-Desmethyl-39,40-O,O-ethylene-rapamycin, (26R)-26-Dihydro-40-O-(2-hydroxyethyl-rapamycin, 28-O-Methyl-rapamycin, 40-O-(2-Aminoethyl)-rapamycin, 40-O-(2-Acetaminoethyl)-rapamycin, 40-O-(2-Nicotinamidoethyl)-rapamycin, 40-O-(2-(N-Methyl-imidazo-2′

-ylcarbethoxamido)ethyl)-rapamycin, 40-O-(2-Ethoxycarbonylaminoethyl)-rapamycin, 40-O-(2-Tolylsulfonamidoethyl)-rapamycin, 40-O-[2-(4′

,5′

-Dicarboethoxy-1′

,2′

,3′

-triazol-1-yl)-ethyl]-rapamycin, 42-Epi-(tetrazolyl)rapamycin (tacrolimus), 42-[3-hydroxy-2-(hydroxymethyl)-2-methylpropanoate]rapamycin (temsirolimus), (42S)-42-Deoxy-42-(1H-tetrazol-1-yl)rapamycin(zotarolimus), salts, derivatives, isomers, racemates, diastereoisomers, prodrugs, hydrate, ester, or analogs thereof.

15. The method of claim 1, wherein said coating on said substrate comprises polylactoglycolic acid (PLGA) at a density greater than 5 volume %.

16. The method of claim 2, wherein the second velocity is in the range from about 0.1 cm/sec to about 100 cm/sec.

17. The method of claim 1, further including the step of sintering said coating at a temperature in the range from about 25°

C. to about 150°

C. to form a dense, thermally stable film on said surface of said substrate.

18. The method of claim 1, further including the step of sintering said coating in the presence of a solvent gas to form said dense, thermally stable film on said surface of said substrate.

19. The method of claim 1, wherein said producing and said contacting steps, at least, are repeated to form a multilayer film.

20. The method of claim 1, wherein said substrate is at least a portion of a medical implant.

21. The method of claim 1, wherein said substrate is an interventional device.

22. The method of claim 1, wherein said substrate is a diagnostic device.

23. The method of claim 1, wherein said substrate is a surgical tool.

24. The method of claim 1, wherein said substrate is a stent.

25. The method of claim 1, wherein said substrate is a medical balloon.

26. The method of claim 1, wherein the coating is non-dendritic as compared to a baseline average coating thickness.

27. The method of claim 26, wherein no coating extends more than 0.5 microns from the baseline average coating thickness.

28. The method of claim 26, wherein no coating extends more than 1 micron from the baseline average coating thickness.

29. The method of claim 1, wherein the coating is non-dendritic such that there is no surface irregularity of the coating greater than 0.5 microns.

30. The method of claim 1, wherein the coating is non-dendritic such that there is no surface irregularity of the coating greater than 1 micron.

31. The method of claim 1, wherein the coating is non-dendritic such that there is no surface irregularity of the coating greater than 2 microns following sintering of the coated substrate.

32. The method of claim 1, wherein the coating is non-dendritic such that there is no surface irregularity of the coating greater than 3 microns following sintering of the coated substrate.