Particles comprising polyamides with pendent optical absorbers and related methods

1. A method comprising:

providing a mixture comprising a polyamide having an optical absorber pendent from a backbone of the polyamide via a backbone nitrogen atom (OAMB-polyamide), a carrier fluid that is immiscible with the OAMB-polyamide, and optionally, an emulsion stabilizer;

mixing the mixture at a temperature greater than a melting point or softening temperature of the OAMB-polyamide and at a shear rate sufficiently high to disperse the OAMB-polyamide in the carrier fluid; and

cooling the mixture to below the melting point or softening temperature of the OAMB-polyamide to form particles in solidified form comprising the OAMB-polyamide and, if included in the mixture, the emulsion stabilizer is associated with an outer surface of the particles;

wherein the particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, wherein D10<D50<D90.

2. The method of claim 1 , wherein the emulsion stabilizer is included in the mixture.

3. The method of claim 2 , wherein at least some of the particles have a void comprising the emulsion stabilizer at a void/polymer interface.

4. The method of claim 2 , wherein the emulsion stabilizer comprises nanoparticles.

5. The method of claim 3 , wherein the void contains carrier fluid.

6. The method of claim 1 , wherein the mixture further comprises a thermoplastic polymer that is not the OAMB-polyamide.

7. The method of claim 6 , wherein the thermoplastic polymer comprises the polyamide but without the optical absorber pendent therefrom.

8. The method of claim 1 , wherein the optical absorber is from a family selected from the group consisting of rhodamines, fluoresceins, coumarins, naphthalimides, benzoxanthenes, acridines, cyanines, oxazins, phenanthridine, pyrrole ketones, benzaldehydes, polymethines, triarylmethanes, anthraquinones, pyrazolones, quinophthalones, carbonyl dyes, diazo dyes, perinones, diketopyrrolopyrrole (DPP), dioxazine dyes, phthalocyanines, indanthrenes, benzanthrone, violanthrones, azo dyes, phthalocyanine dyes, quinacridone dyes, anthraquinone dyes, dioxagine dyes, indigo dyes, thioindigo dyes, perinone dyes, perylene dyes, isoindolene dyes, aromatic amino acids, flavins, derivatives of pyridoxyl, derivatives of chlorophyll, and any combination thereof.

9. The method of claim 1 , wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylene succinamide), polyhexamethylene adipamide, polypentamethylene adipamide, polyhexamethylene sebacamide, polyundecamide, polydodecamide, polyhexamethylene terephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, a semi-aromatic polyamide, an aromatic polyamide, any copolymer thereof, and any combination thereof.

10. The method of claim 1 , wherein the OAMB-polyamide comprises an alkyl linker connecting the backbone of the polyamide to the optical absorber.

11. The method of claim 10 , wherein the alkyl linker has 2-18 carbons.

12. The method of claim 10 , wherein the alkyl linker has 2-6 carbons.

13. The method of claim 1 , wherein the particles have a diameter span of about 0.2 to about 10.

14. The method of claim 1 , wherein the particles have a circularity of about 0.90 to about 1.0.

15. The method of claim 1 , wherein the optical absorber is pendent from the backbone of the polyamide by an ester bond.

16. The method of claim 1 , wherein the carrier fluid is selected from the group consisting of a silicone oil, a fluorinated silicone oil, a perfluorinated silicone oil, a polyethylene glycol, an alkyl-terminal polyethylene glycol, tetraethylene glycol dimethyl ether, a paraffin, a liquid petroleum jelly, a vison oil, a turtle oil, a soya bean oil, perhydrosqualene, a sweet almond oil, a calophyllum oil, a palm oil, a parleam oil, a grapeseed oil, a sesame oil, a maize oil, a rapeseed oil, a sunflower oil, a cottonseed oil, an apricot oil, a castor oil, an avocado oil, a jojoba oil, an olive oil, a cereal germ oil, an ester of lanolic add, an ester of oleic add, an ester of lauric add, an ester of stearic add, a fatty ester, a fatty add, a fatty alcohol, a polysiloxane modified with fatty adds, a polysiloxane modified with fatty alcohols, a polysiloxane modified with polyoxyalkylenes, and any combination thereof.

17. The method of claim 1 , wherein the carrier fluid is selected from the group consisting of a silicone oil, a fluorinated silicone oil, a perfluorinated silicone oil, and any combination thereof.

18. The method of claim 4 , wherein the nanoparticles comprise oxide nanoparticles.

19. A method comprising:

providing a mixture comprising a polyamide having an optical absorber pendent from a backbone of the polyamide (OAMB-polyamide), nanoparticles as an emulsion stabilizer, and a carrier fluid that is immiscible with the OAMB-polyamide;

mixing the mixture at a temperature greater than a melting point or softening temperature of the OAMB-polyamide and at a shear rate sufficiently high to disperse the OAMB-polyamide in the carrier fluid; and

cooling the mixture to below the melting point or softening temperature of the OAMB-polyamide to form particles in solidified form comprising the OAMB-polyamide and the nanoparticles are associated with an outer surface of the particles.

20. The method of claim 19 , wherein the nanoparticles comprise oxide nanoparticles.