Directed assembly of three-dimensional structures with micron-scale features

Abstract

Polyelectrolyte inks comprising a solvent, a cationic polyelectrolyte dissolved in the solvent, and an anionic polyelectrolyte dissolved in the solvent, are described. The concentration of at least one of the polyelectrolytes in the solvent is in a semidilute regime.

1 . An apparatus for the fabrication of microstructures, the apparatus comprising:
 (1) a nozzle comprising an opening having a diameter of at most 10 microns;   (2) a stage below the nozzle for supporting a substrate;   (3) a micropositioner operably connected to at least one of the nozzle and the stage; and   (4) an ink reservoir in fluid communication with the nozzle.   
     
     
         2 . The apparatus of  claim 1 , further comprising a pressure dispensing system operably connected to the ink reservoir. 
     
     
         3 . The apparatus of  claim 1 , wherein the micropositioner is a computer-controlled micropositioner. 
     
     
         4 . The apparatus of  claim 1 , wherein the opening of the nozzle has a diameter of at most 1 micron. 
     
     
         5 . The apparatus of  claim 1 , wherein the opening of the nozzle has a diameter of at least 0.1 micron. 
     
     
         6 . The apparatus of  claim 1 , further comprising a plurality of nozzles. 
     
     
         7 . The apparatus of  claim 6 , further comprising a plurality of substrates on the stage. 
     
     
         8 . The apparatus of  claim 1 , further comprising a substrate on the stage, the substrate comprising a deposition bath. 
     
     
         9 . The apparatus of  claim 8 , wherein the deposition bath is configured to induce gelation of an ink flowed through the nozzle. 
     
     
         10 . The apparatus of  claim 8 , wherein the deposition bath comprises an aqueous solvent. 
     
     
         11 . The apparatus of  claim 8 , wherein the deposition bath comprises an apolar solvent. 
     
     
         12 . The apparatus of  claim 11 , wherein the apolar solvent comprises an alcohol. 
     
     
         13 . The apparatus of  claim 12 , wherein the deposition bath comprises a mixture of isopropyl alcohol and water.