Composites incorporated a conductive polymer nanofiber network
View Patent ↗Methods of forming composites that incorporate networks of conductive polymer nanofibers are provided. Networks of less-than conductive polymers are first formed and then doped with a chemical dopant to provide networks of conductive polymers. The networks of conductive polymers are then incorporated into a matrix in order to improve the conductivity of the matrix. The formed composites are useful as conductive coatings for applications including electromagnetic energy management on exterior surfaces of vehicles.
1. A method of forming a composite incorporating networks of conductive polymer nanofibers, the method comprising the steps of:
(a) providing a colloidal dispersion comprising a self-assembled network of nanofibers comprising a conjugated polymer;
(b) doping the conjugated polymer with a chemical dopant to provide conductive polymers within the self-assembled network of the colloidal dispersion; and
(c) dispersing the colloidal dispersion within a liquid matrix to provide a liquid composite comprising a network of conductive polymer nanofibers, wherein the liquid matrix is selected from the group consisting of a polymer and a polymer precursor.
2. The method of claim 1 further comprising a step of solidifying the liquid composite to provide a solid composite comprising the network of conductive polymer nanofibers in a solid polymer matrix.
3. The method of claim 1 , wherein the colloidal dispersion is formed by temperature-induced self-assembly of the conjugated polymer in a solution.
4. The method of claim 1 , wherein the colloidal dispersion is a fluid colloidal dispersion.
5. The method of claim 1 , wherein the colloidal dispersion is prepared from the mechanical fracture of a gel.
6. The method of claim 5 , wherein the gel is an elastic organogel comprising the self-assembled network of the conjugated polymer.
7. The method of claim 1 , wherein the colloidal dispersion is formed by self-assembly through the gradual change of solvent composition selected from the group consisting of alkanes, aromatics, and halogenated organic molecules.
8. The method of claim 1 , wherein the conjugated polymer is a semiconducting polymer.
9. The method of claim 1 , wherein the conjugated polymer is selected from the group consisting of a polyalkylthiophene, a polydi-alkyl fluorene, a polydithienosilole, a polyphenylene, a poly(3,4-ethylenedioxythiophene), a poly(pyrrole), a polypyrene, a polypyridine, a poly(p-phenylene vinylene), a polycarbazole, a polyaniline, a polyindole or a copolymer of the polymers listed within this group.
10. The method of claim 1 , wherein the chemical dopant is selected from the group consisting of oxidizing agents including iodine, organic soluble sulfonic acids, water-soluble sulfonic acids, organic salts, and acidic polymers.
11. The method of claim 1 , wherein the liquid matrix is selected from the group consisting of a polymerizable resin, an oil-based paint, and an oil-based primer.
12. The method of claim 1 , wherein the step of dispersing the colloidal dispersion within the liquid matrix comprises dilution of the matrix and colloidal dispersion with a volatile organic solvent followed by concentration via solvent evaporation using heat or vacuum.
13. The method of claim 1 , wherein the step of dispersing the colloidal dispersion within the liquid matrix comprises sonication or mechanical blending.
14. The method of claim 1 , wherein the network of conductive polymers nanofibers comprises fibers having an individual length of from 50 nm to 5 microns.
15. The method of claim 1 , wherein the network of conductive polymers nanofibers comprises fibers having a cross-sectional dimension of from 5 nm to 200 nm.
16. The method of claim 1 , wherein the network of conductive polymers nanofibers comprises fibers having a plurality of branch points spaced between 200 nm to 5 microns apart.
17. The method of claim 1 , wherein the colloidal dispersion is from 1 micron to 1 mm in size.