Method of producing electrically conductive polymer and cellulose nanocomposites

Patent metadata

Field	Value
Publication number	US-9620779-B2
Application number	US-201514848580-A
Country	US
Kind code	B2
Filing date	Sep 9, 2015
Priority date	May 12, 2010
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A method is provided for preparing electrically conductive polymer and cellulose nanocomposite particles and nanocomposite materials. Cellulose microparticles coated with a conductive polymer are added to an acid solution for initiating an acid hydrolysis reaction for a prescribed time interval to form conductive polymer coated cellulose nanoparticles. After quenching the acid hydrolysis reaction, the nanoparticles are separated to obtain a colloidal solution of conductive nanoparticles. The conductive nanoparticles may be subsequently formed into a solid nanocomposite material such as a conductive film. Transparent conductive films may be prepared by forming thin layers having a thickness on a micron or submicron scale.

First claim

The invention claimed is:

1. A method of preparing an electrically conducting nanocomposite material, the method comprising the steps of:
providing cellulose microparticles coated with a conductive polymer;
adding the microparticles to an acid solution for initiating an acid hydrolysis reaction;
reacting the microparticles with the acid to form nanoparticles comprising the conductive polymer and the cellulose;
quenching the acid hydrolysis reaction; and
separating the nanoparticles from the acid solution to obtain a colloidal solution of the nanoparticles.

2. The method according to claim 1 further comprising:
pouring the colloidal solution onto a solid surface; and
drying the colloidal solution to obtain a nanocomposite layer.

3. The method according to claim 2 further comprising removing the nanocomposite layer, so that the nanocomposite layer is free-standing.

4. The method according to claim 2 wherein the nanocomposite layer has a thickness suitable for optical transmission.

5. The method according to claim 2 wherein the nanocomposite layer has a thickness on a micron scale.

6. The method according to claim 2 wherein the nanocomposite layer has a thickness on a submicron scale.

7. The method according to claim 1 wherein the conductive polymer is polypyrrole.

8. The method according to claim 1 wherein the conductive polymer is selected from the group consisting of polyaniline, polyindole, polythiophene, poly(3-methylthiophene), poly(N-methyl aniline), and poly(o-toluidine).

9. The method according to claim 1 wherein the step of reacting the microparticles with the acid is performed for a time duration such that an average diameter of the nanoparticles is between about 30 and 50 nanometers, and an average length of the nanoparticles is between about 300 and 500 nanometers.

10. The method according to claim 1 wherein the microparticles comprise microcrystalline cellulose.

11. The method according to claim 1 wherein the step of providing the microparticles comprising cellulose coated with a conductive polymer is performed by:
forming a mixture comprising cellulose microparticles, a monomer and a surfactant;
agitating the mixture to disperse the microparticles and to obtain cellulose microparticles coated with the monomer;
initiating a polymerization reaction to obtain cellulose microparticles coated with a conductive polymer; and
allowing the polymerization reaction to proceed for a prescribed time interval.

12. The method according to claim 11 wherein the step of initiating the polymerization reaction comprises adding an oxidant to the mixture, thereby initiating a polymerization reaction to form cellulose microparticles coated with the conductive polymer.

13. The method according to claim 12 wherein the oxidant is selected from the group consisting of iron (III) chloride hexahydrate, ferric chloride, ammonium persulphate, potassium persulphate, and phosphomolybdic acid hydrate.

14. The method according to claim 11 wherein the microparticles have a mean diameter between about 20 micrometers and about 25 micrometers and a length between about 40 and 60 micrometers.

15. The method according to claim 11 wherein the microparticles comprise fibers having a mean diameter on a micron scale and a length ranging from a micron scale to centimetre scale.

16. The method according to claim 11 wherein the microparticles comprise fibers comprising crystalline structures and amorphous structures.

17. The method according to claim 11 wherein prior to the step of initiating the polymerization reaction, the following steps are performed:
separating the cellulose microparticles coated with the monomer from the mixture; and
rinsing the cellulose microparticles coated with the monomer in a solution of the monomer.

18. The method according to claim 11 wherein said surfactant is selected from the group consisting of: sulfonic naphthalene acid, anthrquinone-2-sulfonic acid, tween-80, naphtalene sulfonic acid, p-dodecylbenzenesulfonic acid, cetyl trimethylammonium bromide, sodium dodecyl sulphate, cetyltrimethylammonium bromide and tritonX-100, alkyl sulfonates, and alkyl aryl sulfonate.

19. The method according to claim 1 wherein the cellulose microparticles coated with the conductive polymer are washed prior to the step of adding the microparticles to the acid solution.

20. The method according to claim 1 wherein the microparticles are washed in a dopant solution comprising a dopant prior to the step of adding the microparticles to an acid solution.

21. The method according to claim 20 wherein the dopant is one of chloride and sulphate.

22. The method according to claim 20 wherein the dopant is chloride and the dopant solution is hydrochloric acid.

Assignees

• Governing Council Univ Toronto

Inventors

• Pitchai-Mydeen Syed Abthagir
• Yan Ning

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/624

  Electric conductive fillers · CPC title

• C08L79/04

  Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors · CPC title

• C08L1/04

  Oxycellulose; Hydrocellulose {, e.g. microcrystalline cellulose} · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title