Vat photopolymerization additive manufacturing of multi-material parts

1. A method of making an article, comprising:

(a) providing a composition comprising two or more types of polymerizable monomers and two or more types of polymerization initiators, wherein the composition comprises a build region, wherein each type of polymerizable monomer is configured to be polymerizable using a respective type of polymerization initiator of the two or more types, and each respective type of polymerization initiator cannot polymerize a different type of polymerizable monomer of the two or more types;

(b) exposing the build region to two or more polymerization stimuli;

(c) polymerizing the two or more types of polymerizable monomers at the build region to provide a polymer layer; and

(d) advancing the polymer layer away from the build region to provide a patterned three-dimensional article containing two or more heterogeneous integrally mixed polymers;

wherein the polymerization stimuli comprise light having at least two predetermined wavelengths, each predetermined wavelength having a predetermined irradiation pattern, and the build region is exposed to the polymerization stimuli concurrently for a predetermined duration.

2. The method of claim 1 , wherein the composition is in the form of a first liquid layer and a second liquid layer, and the build region is at a liquid-liquid interface between the first and second liquid layers;

wherein

at least one of the first liquid layer and the second liquid layer comprises at least one polymerization initiator of the two or more types of polymerization initiators;

at least one of the first liquid layer and the second liquid layer comprises at least one type of polymerizable monomers of the two or more types of polymerizable monomers; and

the second liquid layer has a lower density than the first liquid layer.

3. The method claim 1 , wherein the two or more types of polymerizable monomers are independently selected from acrylate monomers, acrylic acid monomers, epoxy monomers, thiol monomers, vinyl monomers, vinyl amide monomers, vinyl ester monomers, silyl hydride monomers, and vinyl ether monomers.

4. The method of claim 1 , wherein the composition further comprises a monomer of Formula (I)

CH2═CR1—COR2(CH2) n —OH  (I)

wherein:

R1 is H or methyl,

R2 is O or NR3, wherein R3 is H, alkyl, or aryl, and

n is an integer selected from 1 to 10.

5. The method of claim 1 , wherein the composition further comprises one or more types of crosslinking agents.

6. The method of claim 5 , wherein the one or more types of crosslinking agents are selected from trimethylolpropane triacrylate (TMPTA), ethylene glycol diacrylate, 1,6-hexanediol dimethacrylate (HDDA), epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (EPOX), poly (dimethyl siloxane) dimethacrylamide, poly (dimethyl siloxane) acrylamide, poly (ethylene glycol) diacrylate, bisphenol A glycerolate (1-glycerol/phenol) diacrylate, di(ethyleneglycol) diacrylate, pentaerythritol tetraacrylate, 1,1,3,3-tetramethyl-1,3-bis[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]-disiloxane, and diethyleneglycol diacrylate.

7. The method of claim 1 , wherein the two or more types of polymerization initiators are photoinitiators.

8. The method of claim 7 , wherein the photoinitiators are each independently selected from phenyl bis (2,4,6-trimethyl benzoy) phosphine oxide, a triarylsulfonium hexafluoroantimonate salt, 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, H-Nu 660, H-Nu 640, a carbocyanine alkyltriphenyl borate salt, (η6-carbazole)(η5-cyclopentadienyl) iron hexafluorophosphate, (η6-chlorobenzene) (η5-cyclopentadienyl) iron hexafluorophosphate, (η6-alkylcarbazole) (η5-cyclopentadienyl) iron hexafluorophosphate, H-Nu 254, a diphenyl iodonium salt, and a alkyltriphenyl borate salt.

9. The method of claim 1 , wherein the composition further comprises one or more photosensitizers.

10. The method of claim 9 , wherein the one or more photosensitizers are independently selected from 2-ethyl-9,10-dimethoxyanthracene, anthracene, chlorophyll, and camphorquinone.

11. The method of claim 1 , wherein the composition further comprises a pigment selected from titanium dioxide, carbon black, an organic ultraviolet light absorber, an organic visible light absorber, graphene, carbon nanotubes, and any combination thereof.

12. The method of claim 11 , wherein the pigment is present in an amount of 0.001 to 10 percent by weight relative to the composition.

13. The method of claim 1 , wherein the composition further comprises one or more components selected from the group consisting of: ionic liquids, organic solvents, aqueous liquids, salts, miscible high-viscosity liquids, miscible high-density liquids, particles, dyes, polymers, surfactants, and biological agents.

14. The method of claim 1 , wherein the two or more types of monomers form a microphase separation at the build region.

15. The method of claim 1 , further comprising repeating steps (b)-(d) to provide the three-dimensional article.

16. The method of claim 1 , wherein the three-dimensional article comprises a heterogeneous distribution of the two or more integrally mixed polymers.

17. The method of claim 1 , wherein the three-dimensional article has a heterogeneous distribution of mechanical and chemical properties.