A biphasic ink comprises a plurality of attractive particles, a plurality of repulsive particles, and a carrier liquid.
1. A biphasic ink, comprising:
a gel phase comprising a plurality of flocculated particles in a carrier liquid, the flocculated particles comprising attractive particles and an attractive dispersant, and
a fluid phase comprising a plurality of dispersed particles in the carrier liquid, the dispersed particles comprising repulsive particles and a repulsive dispersant, the repulsive dispersant comprising a comb polymer including ionizable and nonionizable side-chains.
2. The biphasic ink of claim 1 , wherein a ratio Wa:Wr is 1:10 to 10:1, Wa is the weight of the attractive particles, and Wr is the weight of the repulsive particles.
3. The biphasic ink of claim 1 , wherein a ratio Wa:Wr is 1:2.5 to 2.5:1, Wa is the weight of the attractive particles, and Wr is the weight of the repulsive particles.
4. The biphasic ink of claim 1 , wherein the attractive particles comprise a polymer, wherein each monomer unit of the polymer comprises an ionizable side-chain.
5. The biphasic ink of claim 1 , wherein the comb polymer is PAA/PEO.
6. The biphasic ink of claim 1 , wherein the carrier liquid is selected from the group consisting of water, methanol, propanol, ethanol, and t-butanol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, acetonitrile, acetic acid, hexamethylphosphoric triamide (HMPA), tetrahydrofuran (THF), N,N-dimethylacetamide, N-methyl-2-pyrrolidone, tetramethyl urea, glycerol, ethylene glycol, and mixtures thereof.
7. The biphasic ink of claim 1 , wherein the carrier liquid comprises water.
8. The biphasic ink of claim 1 , wherein the attractive particles have an average effective diameter of 20 nanometers to 3 microns.
9. The biphasic ink of claim 1 , wherein the repulsive particles have an average effective diameter of 20 nanometers to 3 microns.
10. The biphasic ink of claim 1 , wherein the attractive particles and the repulsive particles are independently selected from the group consisting of metals, ceramic, ceramic precursors, semiconductors, polymers, bioactive agents, and mixtures thereof.
11. The biphasic ink of claim 1 , further comprising a flocculant.
12. The biphasic ink of claim 11 , wherein the flocculant is selected from the group consisting of multivalent salts, cationic polyelectrolytes, anionic polyelectrolytes, and mixtures thereof.
13. The biphasic ink of claim 1 , further comprising a viscosity modifier.
14. The biphasic ink of claim 13 , wherein the viscosity modifier is selected from the group consisting of methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl methylcellulose, guar gum, poly(ethylene oxide), xanthan gum, alginate, starch, polyvinyl alcohol, polyethylene glycol, carrageenan and mixtures thereof.
15. The biphasic ink of claim 1 , wherein the carrier liquid comprises a molarity of 0.1 or greater of monovalent ions.
16. The biphasic ink of claim 15 , wherein the molarity is 0.5 or greater.
17. The biphasic ink of claim 1 , wherein the carrier liquid comprises a molarity of 0.001 or greater of multivalent ions.
18. The biphasic ink of claim 17 , wherein the molarity is 0.01 or greater.
19. The biphasic ink of claim 1 , comprising a total effective volume fraction, φ total,effective , of attractive and repulsive particles of from about 0.3 to about 0.7.
20. The biphasic ink of claim 1 comprising an elastic modulus, G′, of from about 10 3 to about 10 6 Pa.
21. A method for making a biphasic ink, comprising:
forming attractive particles by mixing first particles, a first carrier liquid and an attractive dispersant;
forming repulsive particles by mixing second particles, a second carrier liquid and a repulsive dispersant, the repulsive dispersant comprising a comb polymer including ionizable and nonionizable side-chains;
mixing the attractive particles and the repulsive particles in a combined carrier liquid comprising the first and second carrier liquids, and
forming a gel phase and a fluid phase, the gel phase comprising a plurality of flocculated particles comprising the attractive particles and the attractive dispersant in the combined carrier liquid; and the fluid phase comprising a plurality of dispersed particles comprising the repulsive particles and the repulsive dispersant in the combined carrier liquid, thereby making the biphasic ink.
22. The method of claim 21 , further comprising mixing a flocculant with the biphasic ink.
23. The method of claim 21 , wherein the biphasic ink has a ratio Wa:Wr is 1:10 to 10:1, Wa is the weight of the attractive particles, and Wr is the weight of the repulsive particles.
24. The method of claim 21 , wherein the biphasic ink has a ratio Wa:Wr is 1:2.5 to 2.5:1, Wa is the weight of the attractive particles, and Wr is the weight of the repulsive particles.