c12)  United States Patent  Gross et al.  (10)  Patent No.:  US 10,189,718 Bl  Jan.29,2019  (45)  Date of Patent:  (54)  METHODS FOR CHARGE-TITRATING  PARTICLE ASSEMBLY, AND STRUCTURES  PRODUCED THEREFROM  (56)  References Cited  OTHER PUBLICATIONS  (57)  ABSTRACT  Related U.S. Application Data  31 Claims, 20 Drawing Sheets  Primary Examiner  - Jennifer Wecker  (74)  Attorney, Agent, or Firm  - O’Connor & Company  Barnov et al., "Chemically induced self-assembly of spherical and  anisotropic inorganic nanocrystals," J. Mater. Chem. 2011, 21,  16694.  (Continued)  (Continued)  U.S. PATENT DOCUMENTS  Methods to fabricate tightly packed arrays of nanoparticles  are disclosed, without relying on organic ligands or a  substrate. In some variations, a method of assembling par› ticles into an array comprises dispersing particles in a liquid  solution; introducing a triggerable pH-control substance  capable of generating an acid or a base; and triggering the  pH-control substance to generate an acid or a base within the  liquid solution, thereby titrating the pH. During pH titration,  the particle-surface charge magnitude is reduced, causing  the particles to assemble into a particle array. Other varia› tions provide a device for assembling particles into particle  arrays, comprising a droplet-generating microfluidic region;  a first-fluid inlet port; a second-fluid inlet port; a reaction  microfluidic region, disposed in fluid communication with  the droplet-generating microfluidic region; and a trigger  source configured to trigger generation of an acid or a base  from at least one pH-control substance contained within the  reaction microfluidic region.  (Continued)  (Continued)  (Continued)  (51)  Int. Cl.  (52)  U.S. Cl.  CPC .......  COIF 1710062  (2013.01);  BOJJ 1910046  (2013.01);  COJG 4910045  (2013.01);  ( 58)  Field of Classification Search  CPC .......... B0lJ 19/0046; B0lJ 2219/00331; B0lJ  2219/00585; B0lJ 2219/00599;  Fluid 1  *See FIG. 4B  <---.....  ’  --.......,Trigger source  5,534,461 A  5,591,535 A  7/1996 Kuwajima  l/ 1997 Hisano et al.  (71)  Applicant:  HRL Laboratories, LLC,  Malibu, CA  (US)  (72)  Inventors:  Adam  F.  Gross,  Santa Monica, CA  (US);  Shanying Cui,  Calabasas, CA  (US);  John J. Vajo,  West Hills, CA  (US);  Christopher S. Roper,  Santa  Monica, CA (US)  (73)  Assignee:  HRL Laboratories, LLC,  Malibu, CA  (US)  ( *)  Notice:  Subject to any disclaimer, the term ofthis  patent is extended or adjusted under 35  U.S.C. 154(b) by 242 days.  (21)  Appl. No.:  15/241,536  (22)  Filed:  Aug. 19, 2016  (60)  Provisional application No. 62/212,969, filed on Sep.  1, 2015, provisional application No. 62/213,044, filed  on Sep. 1, 2015.  BOJJ 19100  COJG 49102  (2006.01)  (2006.01)  US010189718Bl 