# US 10,311,993 B2 · Cotton fiber dissolution and regeneration and 3D printing of cellulose based conductive composites

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- Number: US 10,311,993 B2
- Document ID: US10311993B2
- Status: Granted
- Kind: B2
- Application number: 15/355,480
- Filed: 2016-11-18
- Published: 2017-05-18
- Granted: 2019-06-04
- Earliest claimed: 2015-11-18
- Assignees: Texas Tech University System
- Applicants: Texas Tech University System
- Inventors: Noureddine Abidi; Yang Hu
- Web page: https://patentgrep.com/patent/US10311993B2

## CPC

- H01B 1/12: organic substances {(organic macromolecular compounds or compositions C08)}
- B29C 64/112: using individual droplets, e.g. from jetting heads
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 70/10: Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
- B33Y 80/00: Products made by additive manufacturing
- C08B 16/00: Regeneration of cellulose
- C08L 1/02: Cellulose; Modified cellulose
- H10W 20/4473: {Conductive organic materials, e.g. conductive adhesives or conductive inks}
- B29K 2001/00: Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
- B29K 2105/0023: {improving electric conduction}
- B29K 2995/0005: Conductive
- B29L 2031/34: Electrical apparatus, e.g. sparking plugs or parts thereof
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

The present invention includes composition and methods for a core matrix comprising a dissolved cellulose fiber of, e.g., high molecular weight (DP>5000) or microcrystalline cellulose of low molecular weight (DP: 150-300), printed into a two or three dimensional pattern; a conductive material comprising a carbon nanotube or graphene oxide disposed on or about the cellulose fiber or microcrystalline cellulose; and an enhancer or stabilizer that stabilizes the dissolved cellulose or microcrystalline cellulose disrupted during a printing process, wherein the conductive material and the cellulose or microcrystalline cellulose forms one or more features in or on the cellulose fiber or microcrystalline cellulose.

## Claims

### Claim 1

A method for making a 3D printing cotton cellulose-based conductive composite, comprising:
obtaining a core matrix comprising cotton cellulose fibers or cotton microcrystalline cellulose, wherein the cotton cellulose fibers comprise 1-20% of bleached cotton cellulose fiber with a Degree of Polymerization (DP) over 5,000, or the microcrystalline cellulose comprises 5-50% microcrystalline cellulose with a DP of 200-250;
dissolving the cotton cellulose fibers or cotton microcrystalline cellulose in a solvent;
adding a 3D printing process enhancer to stabilize the cotton cellulose fibers or cotton microcrystalline cellulose disrupted during a printing process;
printing, layering or depositing the dissolved cotton cellulose fibers or cotton microcrystalline cellulose and a conductive material; and
stabilizing the printed cotton cellulose fibers or cotton microcrystalline cellulose to form the 3D printing cotton cellulose-based conductive composite.

### Claim 2 (depends on 1)

The method of claim 1, wherein the cotton cellulose fiber or cotton microcrystalline cellulose is freeze-dried before use, or the cotton cellulose fiber or cotton microcrystalline cellulose is freeze-dried prior to dissolving in the solvent to enhance the solubility of cellulose in the solvent.

### Claim 3 (depends on 1)

The method of claim 1, wherein the conductive material is selected from at least one of a carbon nanotube or graphene oxide.

### Claim 4 (depends on 1)

The method of claim 1, further comprising the step of adjusting the amount and viscosity of the dissolved cellulose prior to 3D printing.

### Claim 5 (depends on 1)

The method of claim 1, wherein the solvent is a LiCl/DMAc solvent system in which the cotton cellulose fibers or cotton microcrystalline cellulose is first mixed with DMAc at 80-90° C. for 20 mins., LiCl is added at a temperature of 80-90° C. for 2-4 hrs., cooling down to room temperature and then reheating to 80-90° C. until the cellulose mixture is clear.

### Claim 6 (depends on 1)

The method of claim 1, wherein a carbon nanotube (CNT) solution is separately placed in different ink boxes from the cellulose dissolved in a solvent that is a LiCl/DMAc solvent system, and the CNT and dissolved cellulose are mixed into a cellulose/CNT conductive composite that is printed layer-by-layer with a two-channel 3D printer.

### Claim 7 (depends on 1)

The method of claim 1, wherein a graphene oxide (GO) solution is mixed with an alginate to enhance the viscosity of GO solution, and the GO solution is transferred in different ink boxes with the cellulose dissolved in the solvent that comprises a LiCl/DMAc solvent system, or the composite comprises a centered GO surrounded by cellulose that is printed by a two-channel 3D printer, wherein the composite comprises 1-10% GO mixed with cellulose dissolved in NaOH/urea solvent system and the mixture is stirred for at least 12 hrs. until it appears homogenous, or the composite comprises 1-10% GO mixed with cellulose dissolved in NaOH/urea solvent system and the mixture is mounted in an ink box and printed by the 3D printer to form a membrane-like scaffold.

### Claim 8 (depends on 1)

The method of claim 1, wherein the solvent is a 4-8% NaOH/4-12% urea solvent system that used to dissolve the cellulose prior to printing.

### Claim 9 (depends on 1)

The method of claim 1, wherein the composite is formed into at least one of a photovoltaic cell, a solar cell, a conductive material for biological signal delivery, electrical paper, conductive fabric, one or more wires, transistors, resistors, capacitors, diodes, vias, Thin-Film Transistors (TFT), Random Access Memory (RAM), Static Random Access Memory (SRAM), FRAMs ferroelectric RAM (FRAM), pixels, Liquid Crystal Displays (LCD), Organic LED (OLED), a gate array or programmable read-only memory (PROM), N-type or P-type metal-oxide-semiconductor logic field effect transistors (MOSFETs), n-channel metal oxide semiconductors (NMOS), p-channel metal oxide semiconductors (PMOS), organic thin film transistors (OTFTs), batteries, energy storage, antennas, sensors, or plates.

### Claim 10 (depends on 1)

The method of claim 1, wherein the 3D printing process enhancer is selected from at least one of alginate, gelatin, polyvinyl alcohol, or polylactide.

### Claim 11 (depends on 1)

The method of claim 1, further comprising the step of adding a biopolymer or chitin, or a gel to the dissolved cellulose to form a cellulose-biopolymer, a cellulose-chitin composite, or a cellulose-gel composite.