# US 8,771,628 B2 · Aqueous carbon nanotube applicator liquids and methods for producing applicator liquids thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,628 B2 - Document ID: US8771628B2 - Status: Granted - Kind: B2 - Application number: 12/612,445 - Filed: 2009-11-04 - Published: 2010-03-04 - Granted: 2014-07-08 - Earliest claimed: 2004-12-16 - Assignees: Nantero, Inc. - Applicants: Ramesh Sivarajan; Thomas Rueckes; Rahul Sen; Brent M. Segal; Eliodor G. Ghenciu; Jonathan W. Ward; Tzong-Ru T. Han - Inventors: Ramesh Sivarajan; Thomas Rueckes; Rahul Sen; Brent M. Segal; Eliodor G. Ghenciu; Jonathan W. Ward; Tzong-Ru T. Han - Web page: https://patentgrep.com/patent/US8771628B2 ## CPC - D06M 11/64: with nitrogen oxides; with oxyacids of nitrogen or their salts (with pernitric acids or their salts D06M11/50) - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - B82Y 40/00: Manufacture or treatment of nanostructures - C01B 32/168: After-treatment - C01B 32/17: Purification - D06M 10/02: Sonic or ultrasonic waves; Corona discharge - D06M 11/50: with hydrogen peroxide or peroxides of metals; with persulfuric, permanganic, pernitric, percarbonic acids or their salts - D06M 11/55: with sulfur trioxide; with sulfuric acid or thiosulfuric acid or their salts - C01B 2202/02: Single-walled nanotubes - C01B 2202/28: Solid content in solvents - D06M 2101/40: Fibres of carbon - H10K 71/12: using liquid deposition, e.g. spin coating - H10K 85/221: {Carbon nanotubes} - Y10S 977/746: Modified with biological, organic, or hydrocarbon material - Y10S 977/845: Purification or separation of fullerenes or nanotubes - D06M: TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Certain applicator liquids and method of making the applicator liquids are described. The applicator liquids can be used to form nanotube films or fabrics of controlled properties. An applicator liquid for preparation of a nanotube film or fabric includes a controlled concentration of nanotubes dispersed in a liquid medium containing water. The controlled concentration is sufficient to form a nanotube fabric or film of preselected density and uniformity. ## Claims ### Claim 1 A method for making an applicator liquid, the method comprising: purifying a plurality of nanotubes to obtain purified nanotubes, wherein said step of purifying is accomplished by: contacting said plurality of nanotubes with an acid to create a nanotube-acid solution and dissolve metal impurities, separating the dissolved metal impurities from said nanotube-acid solution to obtain said purified nanotubes in said nanotube-acid solution, and contacting said plurality of nanotubes in the nanotube-acid solution with a base to return the pH level of the nanotube-acid solution to approximately neutral to obtain purified nanotubes; and contacting said purified nanotubes with water; wherein said applicator liquid contains said purified nanotubes distributed in said water without substantial precipitation for at least one hour after said contacting; said applicator liquid is free of polymers and surfactants; and said applicator liquid has a group I metal impurities content of less than 100 ppb. ### Claim 2 (depends on 1) The method of claim 1, wherein said acid is a nitric acid, a hydrochloric acid, or a mixture thereof. ### Claim 3 (depends on 1) The method of claim 1, wherein said base is an ammonia hydroxide, tetramethylammonium hydroxide, alkyl ammonium bases, or combinations thereof. ### Claim 4 (depends on 1) The method of claim 1, wherein said contacting said plurality of nanotubes with a base reduces amorphous carbon impurities. ### Claim 5 (depends on 1) The method of claim 1, wherein said applicator liquid is substantially free of amorphous carbon impurities. ### Claim 6 (depends on 1) The method of claim 1, wherein said step of separating said dissolved metal impurities comprises removing said dissolved metal impurities using centrifugation. ### Claim 7 (depends on 6) The method of claim 6, wherein said centrifugation comprises ultracentrifugation, continuous flow centrifugation, or combinations thereof. ### Claim 8 (depends on 1) The method of claim 1, wherein said purifying comprises oxidizing non-fullerenic carbonaceous materials. ### Claim 9 (depends on 8) The method of claim 8, wherein said oxidizing comprises contacting said plurality of nanotubes with hydrogen peroxide. ### Claim 10 (depends on 8) The method of claim 8, wherein said plurality of nanotubes are heated in an oxygen-containing environment. ### Claim 11 (depends on 1) The method of claim 1, further comprising repeating said purifying a plurality of nanotubes. ### Claim 12 (depends on 1) The method of claim 1, wherein said contacting said purified nanotubes with water comprises grinding said purified nanotubes in water. ### Claim 13 (depends on 1) The method of claim 1, wherein said contacting said purified nanotubes with water comprising agitating said purified nanotubes in water. ### Claim 14 (depends on 1) The method of claim 1, wherein said applicator liquid contains said purified nanotubes distributed in said water at a concentration greater than or equal to 1 mg/L. ### Claim 15 (depends on 1) The method of claim 1, wherein said applicator liquid is substantially free of particulates having a diameter greater than about 500 nm. ### Claim 16 (depends on 1) The method of claim 1, wherein said purifying comprises removing impurities using gravity filtration, cross flow filtration, vacuum filtration, or combinations thereof. ### Claim 17 (depends on 1) The method of claim 1, wherein said applicator liquid has a group I metal impurities content of less than 50 ppb. ### Claim 18 (depends on 1) The method of claim 1, wherein separating said dissolved metal impurities comprises performing a cross-flow filtration process to said acid. ### Claim 19 (depends on 1) The method of claim 1, wherein said step of separating said dissolved metal impurities comprises performing a cross-flow filtration process.