Particles with designed different sized discrete pores

Patent metadata

Field	Value
Publication number	US-9815958-B2
Application number	US-201615133267-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Jan 25, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

Polymeric porous particles have a continuous organic solid phase and at least two sets of discrete pores that are isolated from each other within the continuous phase and that have different average sizes. One set of discrete pores has a larger average size than another set of discrete pores by at least 50%. At least one set of discrete pores is free of detectably different marker materials. There porous particles can be prepared using evaporative limited coalescence techniques with especially chosen discrete pore stabilizing hydrocolloids to protect the pores during formation and to provide the different average sizes. The resulting porous particles can be incorporated into articles of various types and having various shapes.

First claim

The invention claimed is:

1. An article comprising a porous particle that comprises one or more organic polymers that provide a continuous solid phase including an external particle surface, and at least first and second discrete closed pores that are isolated from each other and dispersed within the continuous phase, the first and second discrete closed pores having first and second average sizes,
wherein:
the second average size is greater than the first average size by at least 50%,
the first or second closed discrete pores are free of detectably different marker materials,
the porous particle has a mode particle size of at least 2 μm and up to and including 50 μm, and
the first and second discrete closed pores comprise first and second discrete pore stabilizing hydrocolloids, respectively, which provide different osmotic pressures of at least 0.4 psi.

2. The article of claim 1 comprising a plurality of the porous particles that are adhered to one another through an annealing process, or by chemical attachment.

3. The article of claim 2 that is a molded three dimensional object or film with a designed variation in the index of refraction and density achieved provided by the plurality of the porous particles.

4. The article of claim 1 , wherein the porous particle comprises a marker material present within only the first discrete closed pores or the second discrete closed sized pores.

5. The article of claim 1 , wherein the second average size of the second discrete closed pores is greater than the first average size of the first discrete closed pores by at least 100%.

6. The article of claim 1 , wherein the first discrete closed pores are predominantly nearer the external particle surface of the porous particle compared to the second discrete closed pores.

7. The article of claim 1 , wherein the first and second discrete pore stabilizing hydrocolloids are independently selected from the group consisting of carboxymethyl cellulose (CMC), a gelatin or gelatin derivative, a protein or protein derivative, a hydrophilic synthetic polymer, a water-soluble microgel, a polystyrene sulfonate, poly(2-acrylamido-2-methylpropanesulfonate), and a polyphosphate.

8. The article of claim 1 , wherein the first discrete closed pores have a first average size of at least 0.3 μm and to and including 3 μm, and the second discrete closed pores have a second average size of at least 0.45 μm and to and including 10 μm.

9. The article of claim 1 , wherein there are no detectably different marker materials in the first and second discrete closed pores of the porous particle.

10. The article of claim 1 , wherein there are no detectably different marker materials in any of the first and second discrete closed pores of the porous particle.

11. The article of claim 1 , wherein the porous particle has a porosity of at least 20% and up to and including 50% based on total porous particle volume.

12. A method for preparing a porous particle, comprising:
providing a first water-in-oil emulsion comprising a first discrete pore stabilizing hydrocolloid in a first aqueous phase that is dispersed within a first oil phase containing a first organic polymer or polymer precursor and a first organic solvent,
providing a second water-in-oil emulsion comprising a second discrete pore stabilizing hydrocolloid in a second aqueous phase that is dispersed within a second oil phase containing a second organic polymer or polymer precursor and a second organic solvent,
wherein the first discrete pore stabilizing hydrocolloid in the first aqueous phase has a different osmotic pressure than the second discrete pore stabilizing hydrocolloid in the second aqueous phase, by at least 0.4 psi,

combining the first and second water-in-oil emulsions to form a third water-in-oil emulsion,
dispersing the third water-in-oil emulsion in a third aqueous phase, and removing the first and second organic solvents to form porous particles,
each formed porous particle comprising the first and second organic polymers that provide a continuous organic solid phase including an external particle surface, and at least first and second discrete closed pores that are isolated from each other and dispersed within the continuous organic solid phase, the first and second discrete closed pores having first and second average sizes, respectively, and comprising the first and second discrete pore stabilizing hydrocolloids, respectively,
wherein the second average size is greater than the first average size by at least 50%, and the first or second discrete closed pores are free of detectably different marker materials.

13. The method of claim 12 , wherein the first and second discrete pore stabilizing hydrocolloids in the first and second aqueous phases, respectively, have different osmotic pressures of at least 0.4 psi and to and including 25 psi.

14. The method of claim 12 , wherein the first and second discrete pore stabilizing hydrocolloids are present in the first and second aqueous phases, respectively, at different concentrations.

15. The method of claim 12 , wherein the first and second discrete pore stabilizing hydrocolloids are the same chemical compounds.

16. The method of claim 12 , wherein the first and second discrete pore stabilizing hydrocolloids are different chemical compounds.

17. The method of claim 12 , wherein the first and second discrete pore stabilizing hydrocolloids are present in the first and second aqueous phases at the same concentration.

18. The method of claim 12 , further comprising adding water to the third aqueous phase after dispersing the third water-in-oil emulsion in the third aqueous phase.

19. The method of claim 12 , comprising adding water to the third aqueous phase after dispersing the third water-in-oil emulsion in the third aqueous phase in an amount to provide an osmotic mismatch of at least 0.4 psi with either the first or the second aqueous phase.

20. The method of claim 12 , further comprising:
providing an additional water-in-oil emulsion comprising a discrete pore stabilizing hydrocolloid in an additional aqueous phase that is dispersed within an additional oil phase containing an additional organic polymer or polymer precursor and an additional organic solvent, and
combining the additional water-in-oil emulsion with the first and second water-in-oil emulsions to form the third water-in-oil emulsion.

Assignees

• Boris David Charles
• Hosmer Teresa Joy
• Nair Mridula
• Eastman Kodak Co

Inventors

• Boris David Charles
• Hosmer Teresa Joy
• Nair Mridula

Classifications

• C08J2201/0502

  the liquid phase being organic · CPC title

• C08J9/283 Primary

  a discontinuous liquid phase emulsified in a continuous macromolecular phase · CPC title

• C08J2401/28

  Alkyl ethers · CPC title

• C08J9/0061

  characterized by the use of several polymeric components · CPC title

• C08J2205/048

  Bimodal pore distribution, e.g. micropores and nanopores coexisting in the same foam · CPC title