WO2014201471A1

WO2014201471A1 - Conjugated polymers for conductive coatings and devices

Info

Publication number: WO2014201471A1
Application number: PCT/US2014/042578
Authority: WO
Inventors: Lilo D. POZZO; Pablo DE LA IGLESIA; Gregory M. NEWBLOOM
Original assignee: University Of Washington
Priority date: 2013-06-14
Filing date: 2014-06-16
Publication date: 2014-12-18

Abstract

Described herein are conjugated polymer-surfactant complexes that can provide a stable dispersion or gel. Also provided herein are methods for making a conjugated polymer-surfactant complex (e.g., a poly(3,4-ethylenedioxythiophene)-surfactant complex) directly in a variety of organic solvents, and the use of the resulting conjugated polymer-surfactant complex in applications such as coatings and as paint additives.

Description

CONJUGATED POLYMERS FOR CONDUCTIVE COATINGS AND DEVICES

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Patent Application No. 61/835,076, filed June 14, 2013, the disclosure of which is hereby incorporated by reference in its entirety.

STATEMENT OF GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under DE-SC0010282, awarded by the Department of Energy, and under STTR grant 1346483, awarded by the National Science Foundation. The Government has certain rights in the invention.

BACKGROUND

Electrostatic dissipation is important in many industries, such as the electronics and the aeronautic industry. For example, plastic composites coatings can be used to dissipate electricity to reduce damage caused by electrostatic charge build-up in an electronic product or an electronic component. Low-cost materials can be advantageous to protect large areas with electrostatic dissipation coatings.

To efficiently dissipate the electrostatic charge, a conductive coating should desirably have a sheet resistance within the range of 10⁹-10⁶ ohm/D . Resistance within this range can promote efficient charge mitigation while simultaneously decreasing the likelihood of generation of high electrical currents.

Currently, antistatic coatings can be made of conductive oxides (such as indium tin oxide) or by incorporating additives into paints (such as surfactants or metal nanoparticles). Oxides, albeit very efficient, can be relatively expensive due to the rare materials used for their production. Application of oxides as coating can also be difficult, rendering oxides impractical and expensive for large area antistatic applications. Metal nanoparticles are the most common additives used in the industry, but present many problems. For example, metals have a high density, thereby adding a lot of weight per volume of additive. They can also include metal nanospheres whose geometry requires a very high loading (-20-40 wt %) to percolate a film and adequately dissipate charge. These high loadings compromise adhesion of a metal coating onto a substrate, and can negatively impact optical properties and mechanical properties (e.g., flexibility) of the resulting film.

As an example, the aeronautical industry uses carbon-reinforced composites as structural materials due to their low density, such that the composites can provide large fuel savings due to their relatively light weight. However, these composites can generate large electrostatic build-up due to their low-conductivity, which can compromise the structural stability of a coated aircraft. Thus, to protect the structural stability of the aircraft, a copper mesh is used to dissipate the electrostatic charge. This copper mesh can present numerous problems. For example, as the copper mesh is placed under the composite, it can have decreased efficiency compared to a surface antistatic coating. Furthermore, the weight of the copper mesh can be disadvantageous toward achieving a lightweight aircraft.

Conjugated polymers (CPs) have properties that make them good candidates for electrostatic dissipation additives. CPs are intrinsically conductive materials that can optionally be doped with small organic molecules to increase their conductivity. The properties of CPs can be changed by modifying properties such as solubility, optical properties, chain-chain interactions, and self-assembly. An example of a conjugated polymer that can be used as an electrostatic dissipation additive is poly(3,4- ethylenedioxythiophene) (PEDOT). PEDOT has a high conductivity (500-1200 S/cm) and is a robust degradation-resistant material. PEDOT also has low absorbance in the visible spectrum, which is necessary for making transparent antistatic coatings.

While PEDOT has many properties that are beneficial for antistatic dissipation applications, PEDOT can be difficult to process. Due to its backbone rigidity, it is challenging to disperse PEDOT in a solvent. Thus, to make the polymer processable, PEDOT can be complexed with a compound that dopes the polymer and stabilizes it in dispersion. A common form of PEDOT is an ionic complex of PEDOT with polystyrene sulfate (PSS). The PEDOT:PSS is used to form thin films for organic photovoltaics and organic light emitting diodes. However, PEDOT:PSS is limited to aqueous dispersions and even small additions of other solvents (such as alcohols) will make the dispersion unstable. Because many PEDOT applications, such as additives for antistatic coatings, require the formulation and preparation of dispersions in organic solvents, or mixtures of aqueous and organic solvents (e.g., ethanol, isopropanol), PEDOT:PSS cannot be used for these applications due to its instability in mixed solvent systems. Because many coatings (e.g., those used by the aerospace industry) are based on organic solvents, organic solvent-compatible conductive polymeric additives are needed. The present disclosure seeks to fulfill these needs and provides further related advantages.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In one aspect, this disclosure features a conjugated polymer-surfactant complex having an electrical percolation threshold of less than about 10 wt % when the conjugated polymer-surfactant complex is incorporated into a non-conducting matrix. The conjugated polymer-surfactant complex includes a conjugated polymer and a surfactant associated with the conjugated polymer. The surfactant is selected from the group consisting of a C₆-C₁₆ alkyl sulfonate, a C₆-C₁₆ alkyl sulfate, a C₆-C₁₆ alkylbenzenesulfonate, and any combination thereof.

In another aspect, this disclosure features a corrosion-reducing composite including the conjugated polymer-surfactant complex and a corrosion-reducing material.

In yet another aspect, this disclosure features a battery including the conjugated polymer-surfactant complex.

In yet another aspect, this disclosure features a process of making a conjugated polymer-surfactant complex, including providing mixture that includes an organic solvent; a surfactant selected from the group consisting of a Cg-C^ alkyl sulfonate, a Cg-

Ci6 alkyl sulfate, a Cg-C^ alkylbenzenesulfonate, and any combination thereof; a transition metal cation; and a monomer selected from the group consisting of 3,4- ethylenedioxythiophene, thiophene, pyrrole, aniline, and substituted derivatives thereof. The process includes reacting the mixture to provide a conjugated polymer-surfactant complex. The conjugated polymer-surfactant complex includes a conjugated polymer that includes 3,4-ethylenedioxythiophene, thiophene, pyrrole, or any combination thereof. The conjugated polymer-surfactant complex has an electrical percolation threshold of less than about 10 wt % when the conjugated polymer-surfactant complex is incorporated into a non-conducting matrix. The conjugated polymer-surfactant complex includes a conjugated polymer and a surfactant associated with the conjugated polymer, where the surfactant is selected from the group consisting of a Cg-C^ alkyl sulfonate, a Cg-C^ alkyl sulfate, a Cg-C^ alkylbenzenesulfonate, and any combination thereof.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIGURES 1A-1D are schematic representations of polymer-polymer interactions of embodiments of conductive polymers in organic solvents, with different dopants. FIGURE 1A shows an embodiment of a conductive polymer with no dopant. FIGURE IB shows an embodiment of a conductive polymer with a polymeric dopant. FIGURE 1C shows an embodiment of conductive polymer doped with a solvent-incompatible surfactant, where steric forces are insufficient to form a stable dispersion. FIGURE ID shows an embodiment of a conductive polymer doped with a solvent compatible surfactant, where the polymers form a stable dispersion.

FIGURE 2 is a scheme showing a representative polymerization of an embodiment of a conductive polymer.

FIGURE 3 is a table showing phase behavior for a representative complex of poly(3,4-ethylenedioxythiophene) ("PEDOT") and dodecyl benzene sulfate ("DBS") in chloroform.

FIGURE 4 is a phase diagram for a representative complex of poly(3,4- ethylenedioxythiophene) and DBS in toluene.

FIGURE 5 is a phase diagram for representative complexes of poly(3,4- ethylenedioxythiophene) and surfactants in various solvents.

FIGURE 6 is a phase diagram for representative complexes of poly(3,4- ethylenedioxythiophene) and surfactants in various solvents.

FIGURES 7A-7D are sTEM micrographs of embodiments of poly(3,4- ethylenedioxythiophene)-surfactant complexes in various solvents. FIGURE 7A shows a representative poly(3,4-ethylenedioxythiophene)-dodecyl sulfate ("DS") complex in methanol. FIGURE 7B shows a representative poly(3,4-ethylenedioxythiophene)- dioctyl sulfosuccinate ("AOT") complex in methanol. FIGURE 7C shows a representative poly(3,4-ethylenedioxythiophene)-DBS complex in toluene. FIGURE 7D shows a representative poly(3,4-ethylenedioxythiophene)-DBS complex in methanol.

FIGURES 8A-8C are sTEM micrographs of a representative poly(3,4- ethylenedioxythiophene)-DBS complex dispersed in methanol, after removing excess iron-surfactant salt. FIGURES 8D-8F are sTEM micrographs of a representative poly(3,4-ethylenedioxythiophene)-AOT complex dispersed in methanol, after removing excess iron-surfactant salt. FIGURE 8G-8I are sTEM micrographs of a representative poly(3,4-ethylenedioxythiophene)-DS complex dispersed in methanol, after removing excess iron-surfactant salt.

FIGURE 9 A is a graph showing a representative poly(3,4- ethylenedioxythiophene)-DBS complex concentration vs. bulk conductivity, probing at 10 kHz and 0.6 V.

FIGURE 9B is a graph showing a representative poly(3,4- ethylenedioxythiophene)-AOT complex concentration vs. bulk conductivity, probing at 10 kHz and 0.6 V.

FIGURE 10 is a photograph of a steel coupon showing a width of a corrosion zone (c_w) and a width of a scribe (c_s).

FIGURE 11 is a graph showing a representative polypyrrole-DBS complex concentration vs. bulk conductivity, probing at 10 kHz and 0.6 V.

FIGURES 12A-12C are photographs of carbon steel coupons with painted portions showing corrosion of the coupons immediately after paint stripping (left of each photograph) and one day after stripping with clay added to highlight the corrosion depth (right of each photograph). FIGURE 12A: paint primer without zinc particle additives. FIGURE 12B: paint primer with 30 wt % zinc particle additives. FIGURE 12C: paint primer with 90 wt % zinc particle additives.

FIGURE 13 A is a schematic representation of a representative conductive polymer network interconnecting zinc particles within a paint.

FIGURE 13B is a photograph of carbon steel coupons painted with a 6 wt % of a representative conductive polymer composition and 30 wt % zinc particles.

FIGURE 14 is a photograph of carbon steel coupons painted with a 6 wt % a representative conductive polymer composition.

FIGURE 15 is a graph showing the viscosity of embodiments of paints. DETAILED DESCRIPTION

Described herein are conjugated polymer-surfactant complexes that can provide a stable dispersion or gel. Also provided herein are methods for making a conjugated polymer-surfactant complex (e.g., poly(3,4-ethylenedioxythiophene)-surfactant complex) directly in a variety of organic solvents, and the use of the resulting conjugated polymer- surfactant complex in applications such as coatings and paint additives.

Formulations of conjugated polymer-surfactant complex of the present disclosure can result in a stable dispersion or a gel. The conjugated polymer-surfactant complex can be used as low-cost additives that can be used in existing paints and coatings to render these conductive. The conjugated polymer-surfactant complex of the present disclosure can have an electrical percolation threshold of 10 wt % or less when incorporated in a non-conducting matrix. Furthermore, certain conjugated polymer-surfactant complexes are transparent, such that they can provide conductive properties in top-coats and in applications requiring high-transparency (e.g., windows and cockpits).

Definitions

At various places in the present specification, substituents of compounds of the disclosure are disclosed in groups or in ranges. It is specifically intended that the disclosure include each and every individual subcombination of the members of such groups and ranges. For example, the term "Ci -Cg alkyl" is specifically intended to individually disclose methyl, ethyl, C3 alkyl, C4 alkyl, C5 alkyl, and Cg alkyl.

It is further appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, can also be provided in combination in a single embodiment.

Conversely, various features of the disclosure which are, for brevity, described in the context of a single embodiment, can also be provided separately or in any suitable subcombination.

As used herein, the term "substituted" or "substitution" is meant to refer to the replacing of a hydrogen atom with a substituent other than H. For example, an "N-substituted piperidin-4-yl" refers to replacement of the H atom from the NH of the piperidinyl with a non-hydrogen substituent such as, for example, alkyl.

As used herein, the term "alkyl" refers to a straight or branched chain fully saturated (no double or triple bonds) hydrocarbon (carbon and hydrogen only) group. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tertiary butyl, pentyl and hexyl. As used herein, "alkyl" includes "alkylene" groups, which refer to straight or branched fully saturated hydrocarbon groups having two rather than one open valences for bonding to other groups. Examples of alkylene groups include, but are not limited to methylene, -CH₂-, ethylene, -CH₂CH , propylene, -CH₂CH₂CH , n-butylene, -CH₂CH₂CH₂CH₂-, sec-butylene, and -CH₂CH₂CH(CH₃)-. An alkyl group of this disclosure may optionally be substituted with one or more fluorine groups.

As used herein, the term "aryl" refers to monocyclic or polycyclic (e.g., having 2, 3 or 4 fused rings) aromatic hydrocarbons such as, for example, phenyl, naphthyl, anthracenyl, phenanthrenyl, indanyl, and indenyl. In some embodiments, aryl groups have from 6 to about 20 carbon atoms.

As used herein, the term "halo" or "halogen" includes fluoro, chloro, bromo, and iodo.

As used herein, the term "constitutional unit" of a polymer refers an atom or group of atoms in a polymer, comprising a part of the chain together with its pendant atoms or groups of atoms, if any. The constitutional unit can refer to a repeat unit. The constitutional unit can also refer to an end group on a polymer chain. For example, the constitutional unit of polyethylene glycol can be -CH₂CH₂0- corresponding to a repeat unit, or -CH₂CH₂OH corresponding to an end group.

As used herein, the term "repeat unit" corresponds to the smallest constitutional unit, the repetition of which constitutes a regular macromolecule (or oligomer molecule or block)

As used herein, "surfactant" or "surfactant dopant" refers to organic compounds that are amphiphilic, such that they contain both hydrophobic groups (tails) and hydrophilic groups (heads). A surfactant contains both a water-insoluble component and a water-soluble component.

As used herein, "dispersion" refers to a system where particles (e.g., polymer particles) are dispersed in a continuous phase of a different composition (e.g., a liquid medium, such as a solvent).

As used herein, "gel" refers to a three-dimensional polymeric network that spans the volume of a liquid medium and ensnares it through surface tension effects. The polymer's internal network structure can result from physical bonds or chemical bonds, as well as crystallites or other junctions that remain intact within the liquid medium.

As used herein, "conjugated polymer" or "conductive polymer" refers to organic polymers having alternating single and double bonds along the polymer backbone. When doped, the conductivity of the conjugated polymer/conductive polymer can increase by several orders of magnitude.

As used herein, a "composite" material refers to materials made from two or more constituent materials with different physical and/or chemical properties. When combined, a material with different characteristics from the individual components is produced. The individual components remain separate and distinct in the composite. The composite can include a matrix material in which are embedded other components that form the composite.

As used herein, a polymer's "primary structure" refers to the structure of the polymer backbone, side chain, and dopant.

As used herein, a polymer's "secondary structure" refers to the structure that results from the interaction of polymer chains with one-another. For example, conjugated polymers have been reported to aggregate and/or crystallize via self- or directed-assembly mechanisms into multiple form factors (e.g., spheres, rods, plates, etc.).

As used herein, a polymer's "tertiary structure" refers to the structure resulting from the interactions of the form factors in the secondary structure to form a network-like tertiary structure. The interactions between the form factors in the secondary structure are typically physical, ranging from form factors that are barely in contact with one another to secondary structures that are fused together (e.g., in a dense pearl necklace conformation). The "tertiary structure" can be fractured into "secondary structures" upon the application of an external force (e.g., shear).

As used herein, "percolation threshold" or "electrical percolation threshold" refers to the formation of long range (e.g., > 1 cm) connectivity of a conductive material (e.g., > 10^~12 S/cm) in a non-conductive (e.g., < 10^~12 S/cm) medium (e.g., air, water, solvent, polymer, etc.). Below the percolation threshold, the conductive material (or particle) does not form a continuous path over a long range. Above the percolation threshold, the conductive material does form a continuous path over a long range. The continuous path allows for the transport of electric charge (i.e., holes or electrons) throughout the interconnected conductive material within the non-conductive medium. As used herein, "specific surface area" refers to a total accessible surface area of a conjugated polymer-surfactant complex relative to its total mass (i.e., m²/g).

As used herein, "accessible surface area" refers to the surface area of the conjugated polymer-surfactant complex that is in contact with a secondary phase (e.g., air, solvent, etc.).

As used herein, "Bjerrum length" refers to a separation in which the thermal energy is equal to the Coulombic energy between two polymer chains (i.e., the minimum distance that polymer chains or particles should stay separated to have zero electrostatic (i.e., charge) interactions).

As used herein, "form factor" refers to the 3-dimensional shape of the smallest polymer particle that is identifiable at greater than a molecular scale of 10^~9 m and less than a micro scale of 10^~5 m.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Conducting polymer-surfactant complex

In one aspect, a conjugated polymer-surfactant complex that forms stable dispersions or polymer gels is provided. The conjugated polymer is associated with any surfactant dopant that can provide a stable dispersed conjugated polymer-surfactant complex in an organic solvent. For example, the conjugated polymer can be associated with a sulfonate or sulfate surfactant dopant, such as a C₆-C₁₆ alkyl sulfonate, a C₆-C₁₆ alkyl sulfate, and/or a Cg-C^ alkylarylsulfonate (e.g., a Cg-C^ alkylbenzenesulfonate).

The association can be non-covalent and occur instead via ionic interactions, via hydrogen bonds, and/or via van der Waals interactions. The conjugated polymer is associated with the surfactant (i.e., the surfactant dopant) at a surfactant to constitutional unit ratio of less than 1 : 1. In some embodiments, the conjugated polymer is associated with the surfactant at a surfactant to constitutional unit ratio of less than 1 :2 (i.e., less than

1 surfactant per 2 repeat units). For example, the conjugated polymer can be associated with the surfactant at a surfactant to constitutional unit ratio of less than 1 :2 (e.g., less than 1 :3, less than 1 :4, less than 1 :5, or less than 1 :6). In some embodiments, the conjugated polymer is associated with the surfactant at a surfactant to constitutional unit ratio of between 1 :2 and 1 :6 (e.g., between 1 :2 and 1 :5, between 1 :3 and 1 :5, or between 1 :3 and 1 :6)

The mechanism of conjugated polymer aggregation and dispersion is shown in FIGURES 1A-1D, which provide schematic representations of polymer-polymer interactions in organic solvents, with different dopants, for a rigid conjugated polymer. FIGURE 1A shows a conjugated polymer 100 (e.g., PEDOT, polypyrrole, etc.) with no ionic dopants, such that polymer 100 is aggregated in an organic solvent. Without wishing to be bound by theory, it is believed that the rigid polymer backbone facilitates the uncontrollable aggregation of the polymer strands, rendering the polymer difficult to disperse in a given solvent.

FIGURE IB shows a conjugated polymer 110 (e.g., PEDOT) that is associated with an ionic polymer 120 having an electrostatic charge (e.g., polystyrene sulfonate). The ionic polymer 120 can interact with conjugated polymer 110 by doping the conjugated polymer with ionic groups (e.g., sulfonate groups) and by stabilizing the conjugated polymer strands via the electrostatic interactions of the ionic groups, which do not interact with conjugated polymer 110. However, the conjugated polymer 110-ionic polymer 120 complex aggregates in an organic solvent as the electrostatic charge of ionic polymer 120 is insufficient to overcome the polymer aggregation effects. Without wishing to be bound by theory, it is believed that the polymer aggregates because the Bjerrum length in organic solvents increases (e.g., compared to the Bjerrum length in water) due to the relatively low dielectric constant of the relatively non-polar solvents, thus rendering the stabilizing effect of ionic polymers ineffective.

FIGURE 1C shows a conjugated polymer 130 that is associated with a surfactant 140 that is incompatible with the solvent, or where the steric repulsion between the surfactant groups is insufficient to overcome the polymer aggregation effects, such that the polymer 130-surfactant 140 complex remains aggregated. Without wishing to be bound by theory, it is believed that if an alkyl and/or aryl group is attached to a sulfonate (or sulfate) group instead of polystyrene, the steric interactions of the dopant chains can stabilize a conjugated polymer in dispersion. However, the alkyl and/or aryl choice is important to form a stable dispersion. If the alkyl and/or aryl group is too small and/or is not compatible with the solvent, the conjugated polymer does not form a stable dispersion and aggregates.

FIGURE ID shows a conjugated polymer 150 that is associated with a surfactant dopant 160 that is compatible with the solvent and/or that is capable of providing sufficient steric repulsion to overcome polymer aggregation effects. A stable dispersion 170 is provided, where chains of polymer 150 complexed with surfactant dopant 160 are independently solvated in the solvent. Here, the complex of conjugated polymer 150- surfactant dopant 160 remains stable in the organic solvent and provides a processable polymer (e.g., a polymer that can provide a homogeneous film or that can mix with a matrix).

Representative conjugated polymers of the present disclosure include poly(3,4- ethylenedioxythiophene), polypyrrole, polythiophene, and/or polyaniline. In some embodiments, the conjugated polymers can have side chains that include, for example, halo, alkyl, and haloalkyl. In some embodiments, the conjugated polymer is poly(3,4- ethylenedioxythiophene). In certain embodiments, the conjugated polymer is polypyrrole.

Representative surfactants dopants include dodecyl sulfate, branched octyl sulfate, hexadecyl sulfate, dodecylbenzene sulfonate, dioctyl sulfosuccinate, naphthalene sulfonates, C₆-C₁₆ alkyl sulfonates such as hexyl sulfonate and octyl sulfonate, and any combination thereof.

Any conjugated polymer described above can be combined with any surfactant dopants, described above.

In some embodiments, the conjugated polymer-surfactant complex forms a dispersion that is stable over an extended period of time, such that the dispersion remains as a homogeneous suspension or solution with no visible precipitation of the conjugated polymer. In some embodiments, the dispersion's optical properties (e.g., transparency, optical absorbance, or color) remain constant over an extended period of time. For example, the conjugated polymer-surfactant complex can remain dispersed in a solvent over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

The solvent can be any organic solvent, or a mixture of solvents that includes at least one organic solvent. Non-limiting examples of solvents include alcohol (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert- butanol, etc.), toluene, xylenes, chlorobenzene, chloroform, hexane, and cyclohexane.

In some embodiments, instead or in addition to forming a dispersion, the conjugated polymer-surfactant complex forms a gel. The gel can remain stable over an extended period of time, such that the gel's optical properties (e.g., transparency, optical absorbance, or color) remain constant over an extended period of time. For example, the conjugated polymer-surfactant complex can remain as a gel over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, the conjugated polymer-surfactant complex, when coated onto a substrate, can have a conductivity of sheet resistance of 10⁵ Ω/D or more (e.g., 106 Ω/Ώ or more, 107 Ω/Ώ or more, 108 Ω/D or more) and/or 10⁹ Ω/D or less (e.g., 108 Ω/D or less, 107 Ω/D or less, 106 Ω/D or less). In some embodiments, the conjugated polymer-surfactant complex, when in the form of a gel, can have a resistivity of 10^"3 S/m or more (e.g., 10^~2 S/m or more, 10^"1 S/m or more) and/or 1 S/m or less (e.g., 10^"1 S/m or less, 10^"2 S/m or less).

In some embodiments, the conjugated polymer-surfactant complex has a specific surface area of at least 10 m²/g. Without wishing to be bound by theory, it is believed that a conjugated polymer-surfactant complex having a higher specific surface area can better encapsulate additives (e.g., Zn) than a conjugated polymer-surfactant complex having a lower specific surface area, due to increased interfacial contact between the conjugated polymer-surfactant complex and the encapsulated additives. In general, a conjugated polymer-surfactant complex having a higher surface area can also have lower electrical percolation thresholds due to its higher porosity. Specific surface area can be measured using a variety of methods, including the use of Brunauer-Emmett- Teller (BET) instruments and small angle neutron scattering (SANS). In some embodiments, a standard Porod plot is used to determine the specific area of a structure, as described, for example, in Lindner, P., Neutrons, X-Rays and Light: Scattering Methods Applied to Soft Condensed Matter. Elsevier Science: Amsterdam, 2002, incorporated herein by reference. In some embodiments, the specific surface area is influenced by synthetic methods and/or assembly processes. When a conjugated polymer-surfactant complex is coated onto a substrate, the specific surface area of the conjugated polymer-surfactant complex can be maintained. In some embodiments, the conjugated polymer-surfactant complex can be transparent. For example, the conjugated polymer-surfactant complex can have an optical transmittance of up to 90 % (e.g., up to 80 %, up to 70 %) in the UV-visible range (e.g., from about 400 nm to 1000 nm).

Electrical percolation threshold

As discussed above, conjugated polymers are intrinsically semi-conducting materials that can be chemically doped to raise their conductivity to the same level as metals (e.g., > 1000 S/cm). Without wishing to be bound by theory, it is believed that a polymer primary structure - which includes the backbone chemistry (i.e., intrinsic charge decolonization), shape (e.g., conformation, aggregation, crystallization), and dopant level (i.e., charge carrier concentration) of the conjugated polymer - determines its intrinsic conductivity. In some embodiments, a secondary structure of conjugated polymers has an intrinsic effect on the conductivity where crystallization (i.e., interchain pi-pi stacking) leads to much higher conductivities than aggregated conjugated polymers, even if the form factors are similar. The conjugated polymers can also have a tertiary structure which influences polymer conductivity. Without wishing to be bound by theory, it is believed that the conducting polymer-surfactant complex of the present disclosure has a primary, a secondary, and a tertiary structure, and the secondary and tertiary structures determine the electrical percolation threshold.

As an example, even if generally beneficial "secondary structures" such as high aspect ratio rods were aggregated in a parallel fashion (e.g., the formation of a thicker rod), the resulting electrical percolation threshold would be relatively high as the resulting polymer structures cannot conduct well from one polymer rod to another. Conversely, a spherical secondary structure, generally considered to be a poor conductor, can be arranged end-to-end (e.g., in a pearl necklace configuration), and the resulting structure would have a relatively low percolation threshold. Therefore, the interaction of secondary and tertiary structures can provide unique conductive properties.

Non-limiting factors that influence secondary and tertiary structures, which in turn influence the electrical percolation threshold of a conjugated polymer-surfactant complex, include: (1) the stability and solubility of the surfactant in a given solvent, where surfactants having higher hydrophilic-lipophobic balance (HLB) can result in smaller secondary and/or tertiary structures; and (2) reaction and/or self-assembly kinetics, where the reaction and/or self-assembly kinetics of conjugated polymers change the resulting secondary and/or tertiary structures. The reaction and/or self-assembly kinetics can be influenced by varying solvents, temperatures, salt concentrations, monomer concentrations, and other reaction or self-assembly conditions. Without wishing to be bound by theory, it is believed that faster kinetics generally lead to denser conjugated polymer-surfactant complexes that have higher electrical percolation thresholds than conjugated polymer-surfactant complexes formed under slower kinetic conditions.

The conjugated polymer-surfactant complex of the present disclosure has an electrical percolation threshold of less than about 10 wt %, when the conjugated polymer- surfactant complex is incorporated into a non-conducting matrix, due to the secondary and tertiary structures of the conjugated polymers-surfactant complex. In some embodiments, the electrical percolation threshold of the conjugated polymer-surfactant complex is 10 wt % or less (e.g., 8 wt % or less, 6 wt % or less, 4 wt % or less, or 2 wt % or less) and/or 2 wt % or more (e.g., 4 wt % or more, 6 wt % or more, or 8 wt % or more). In some embodiments, the electrical percolation threshold percolation is determined by measuring the conductivity of a concentrated conjugated polymer-surfactant dispersion and the conductivities of serially diluted dispersions. Conductivity measurements are taken over a concentration range of at least 2 orders of magnitude. The electrical percolation threshold is the point at which there is an exponential change in conductivity with increasing concentration.

The non-conducting matrix can include any material that can be used to embed the conjugated polymer-surfactant complex. Non-limiting examples of non-conducting matrix material include a non-conducting polymer and/or a paint. Non-limiting examples of non-conducting polymers include poly(lactic acid), polyurethanes, polysiloxanes, poly(methyl methacrylate), polyethylene, polypropylene, uv-curable resins, epoxies (e.g., two-part epoxies), and/or polyethylene terephthalate.

Mesoscale structures

When formed into a film, the conjugated polymer-surfactant complex can organize into secondary structures that are mesoscale in size (i.e., mesostructures). The mesostructure can have features having a size of from 10^~7 to 10^~4 m. Non- limiting examples of mesostructures include plates, lamella, fibers (branched and unbranched), rods, spheres, hollow cylinders, core-shell particles, etc. Examples of mesostructures are also described, for example, in Gong, J. P. et al., Advanced Materials 2003, 15, (14), 1155-1158; Na, Y.-H. et al, Macromolecules 2004, 37, (14), 5370-5374; Li, J. L. et al, Crystal Growth & Design 2010, 10, (6), 2699-2706; Liu, X. Y. and Sawant, P. D. Advanced Materials 2002, 14, (6), 421-426; James, S. L. Chemical Society Reviews 2003, 32, (5), 276-288; Newbloom, G. M. et al, Macromolecules 2012, 45, (8), 3452-3462. Wang, P. S. et al., Macromolecules 2008, 41, (17), 6500-6504, each of which is incorporated herein by reference. The mesostructures can further aggregate into networks, which can electrically percolate a composite in which they are embedded. Process of making the conducting polymer

Referring to FIGURE 2, metal-surfactant salts (as shown, MRx, where M is a metal cation, R is a surfactant, and x indicates the number of R groups) can oxidize a monomer (as shown, a 3,4-ethylenedioxythiophene monomer) and drive the polymerization reaction. As the monomer is polymerized by the metal cations in the presence of the surfactants, the organic surfactant binds to the growing polymer chain with the 'tail' of the surfactant (e.g., an alkyl chain) exposed towards the solvent. This strong association results in a significant increase in entropy and, as a result, in the formation of a stable dispersion of conjugated polymer-surfactant complexes. The conjugated polymer is also highly doped by the interaction with the ionic head group of the surfactant, thereby increasing its electrical conductivity.

In another aspect, the disclosure provides a process of making the conjugated polymer-surfactant complex. The process includes providing a mixture of an organic solvent; a surfactant; a metal cation; and a monomer selected from the group consisting of 3,4-ethylenedioxythiophene, thiophene, pyrrole, aniline, and substituted derivatives thereof (e.g., substituted with halo, alkyl, and/or haloalkyl); and reacting the mixture to provide a conjugated polymer of 3,4-ethylenedioxythiophene, thiophene, pyrrole, and/or aniline that is associated with the surfactant.

Non-limiting examples of organic solvents and surfactants are as discussed above.

The metal cation can be any transition metal cation that can be used to oxidatively couple the monomer to form the conjugated polymer. One example of a suitable metal cation is Fe(III). Other non-limiting examples of suitable metal cations include V(III) and Au(III).

In some embodiments, the mixture includes a metal-surfactant salt that is generated prior to incorporation into the mixture, for example, in a separate reaction. The metal-surfactant salt can be isolated from the separate reaction before addition into the mixture. In other embodiments, the metal-surfactant salt is generated in situ in the mixture, for example, by adding a metal cation (e.g., iron (III), such as FeC^) and a surfactant to the mixture.

In some embodiments, the process for making the conjugated polymer-surfactant complex includes the synthesis and selection of iron (Ill)-surfactant salts such as iron (III) dodecyl sulfate (Fe(Ci₂H₂₅S0₄)3), iron (III) hexadecyl sulfate (Fe(Ci₆H₃₃S0₄)₃) or iron (III) dodecyl benzene sulfate (Fe(Ci₈H₂₉S0₄)₃) along with the selection of the relative concentration of monomer and salt, the solvent and the polymerization temperature. Under certain conditions the polymerization can proceed very efficiently and it is possible to obtain stable, fluid and fully dispersed conjugated polymer-surfactant complexes or, under other conditions, conjugated polymer-surfactant gels in aromatic, halogenated or aliphatic solvents.

In some embodiments, the selection of the transition metal-surfactant salt is important because certain salts will not result in stable dispersions while others will. Another important factor to the formation of stable dispersions is the concentrations of monomer and salt in the initial polymerization solution. For example, when the monomer concentration is high, the growing polymer chains can interact strongly with each other and a highly conductive elastic gel can form. The concentration of iron-surfactant salt also affects the structure because different iron-surfactant salts can self-assemble into organized assemblies (e.g., reverse micelles) that incorporate the iron ions. Depending on temperature and concentration, worm-like and spherical micelles can form in the iron- surfactant salt solutions, which can have an effect on the structure of the synthesized conjugated polymer-surfactant complex.

While the description below refers to FIGURES 3-6, which show phase diagrams for the polymerization of 3,4-ethylenedioxythiophene in various solvents using different surfactants, it is believed that FIGURES 3-6 also apply to the polymerization of pyrrole, and/or substituted derivatives of 3,4-ethylenedioxythiophene and pyrrole.

In some embodiments, the organic solvent is chloroform, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 3, when the organic solvent is chloroform and the surfactant is dodecylbenzenesulfonate, the monomer concentration can be 0.5 mg/ml and the monomer to transition metal cation mole fraction can be 0.2; the monomer concentration can be 1 mg/ml and the monomer to transition metal cation mole fraction can be 0.5; the monomer concentration can be 2 mg/ml and the monomer to transition metal cation mole fraction can be 2; the monomer concentration can be 5-10 mg/ml and the monomer to transition metal cation mole fraction can be 2; the monomer concentration can be 20 mg/ml and the monomer to transition metal cation mole fraction can be 5; or the monomer concentration can be 30 mg/ml and the monomer to transition metal cation mole fraction can be 10; or the monomer concentration can be 50 mg/ml and the monomer to transition metal cation mole fraction can be 20. The synthesized conjugated polymer-surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, the organic solvent is chloroform, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring again to FIGURE 3, the monomer concentration can be 2 mg/ml and the monomer to transition metal cation mole fraction can be 0.2; the monomer concentration can be 3-7 mg/ml and the monomer to transition metal cation mole fraction can be 0.2-0.3; the monomer concentration can be 4-7 mg/ml and the monomer to transition metal cation mole fraction can be 0.2-0.5; the monomer concentration can be 7 mg/ml and the monomer to transition metal cation mole fraction can be 0.2-1 ; the monomer concentration can be 7-50 mg/ml and the monomer to transition metal cation mole fraction can be 1; the monomer concentration can be 20-50 mg/ml and the monomer to transition metal cation mole fraction can be 1-2; the monomer concentration can be 30-50 mg/ml and the monomer to transition metal cation mole fraction can be 1-5; or the monomer concentration can be 50 mg/ml and the monomer to transition metal cation mole fraction can be 1-10. The synthesized conjugated polymer- surfactant complex can be a gel.

In some embodiments, the organic solvent is toluene and the surfactant is dodecylbenzenesulfonate, the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 4, the monomer concentration can be 0.5 mg/ml and the monomer to transition metal cation mole fraction can be 1-5; the monomer concentration can be 0.5-1 mg/ml and the monomer to transition metal cation mole fraction can be 2-5; or the monomer concentration can be 1 mg/ml and the monomer to transition metal cation mole fraction can be 2-5. The synthesized conjugated polymer-surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year). In some embodiments, the organic solvent is toluene, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, , pyrrole, and/or substituted derivatives thereof. Referring again to FIGURE 4, the monomer concentration can be 0.5 mg/ml and the monomer to transition metal cation mole fraction can be 0.5-0.75; the monomer concentration can be 0.5-5 mg/ml and the monomer to transition metal cation mole fraction can be 0.5; the monomer concentration can be 2-5 mg/ml and the monomer to transition metal cation mole fraction can be 0.5-2; the monomer concentration can be 4-5 mg/ml and the monomer to transition metal cation mole fraction can be 0.5-5. The synthesized conjugated polymer- surfactant complex can be a gel.

In some embodiments, the organic solvent is methanol, the surfactant is dodecylsulfate or dodecylbenzenesulfonate, and the monomer is 3,4- ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 5, when the organic solvent is methanol and the surfactant is dodecylsulfate, the monomer concentration can be 0.5-1 mg/ml and the monomer to transition metal cation mole fraction can be 1. Referring again to FIGURE 5, when the organic solvent is methanol and the surfactant is dodecylbenzenesulfonate, the monomer concentration can be 2 mg/ml and the monomer to transition metal cation mole fraction can be 1. The synthesized conjugated polymer-surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, the organic solvent is hexanes, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring again to FIGURE 5, the monomer concentration can be 0.5-5 mg/ml and the monomer to transition metal cation mole fraction can be 1. The synthesized conjugated polymer-surfactant complex can be a gel.

In some embodiments, the organic solvent is cyclohexane, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring again to FIGURE 5, the monomer concentration can be 1-5 mg/ml and the monomer to transition metal cation mole fraction can be 1. The synthesized conjugated polymer-surfactant complex can be a gel.

In some embodiments, the organic solvent is toluene, the surfactant is dioctyl sulfosuccinate and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 6, when the solvent is toluene, the monomer concentration can be 0.5-1 mg/ml and the monomer to transition metal cation mole fraction can be 0.5. The synthesized conjugated polymer- surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, the organic solvent is methanol, the surfactant is octyl sulfonate and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 6, when the solvent is methanol, the monomer concentration can be about 1 mg/ml and the monomer to transition metal cation mole fraction can be 0.5. The synthesized conjugated polymer- surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, the organic solvent is methanol, the surfactant is 2-ethyl- hexyl sulfate and the monomer is 3,4-ethylenedioxythiophene, pyrrole, and/or substituted derivatives thereof. Referring to FIGURE 6, when the solvent is methanol, the monomer concentration can be about 3-6 mg/ml and the monomer to transition metal cation mole fraction can be 0.5. The synthesized conjugated polymer- surfactant complex can remain dispersed in a solution over a period of at least 2 weeks (e.g., at least 1 month, at least 2 months, at least 6 months, or at least one year).

In some embodiments, after the conjugated polymer-surfactant complex has been synthesized, excess metal salts can be removed by repeatedly washing the conjugated polymer-surfactant complex using a solvent that dissolves the metal salt, but that does not dissolve the conjugated polymer-surfactant complex. Washing can be carried out until little (e.g., no) further metal salt is removed from the conjugated polymer-surfactant complex. The amount of metal salt that is removed and that remains in the conjugated polymer-surfactant complex can be monitored using measuring the UV-VIS absorbance of the washing fluid and the conjugated polymer-surfactant complex, respectively.

Methods of using the conducting polymer-surfactant complex

The conjugated polymer-surfactant complex of the present disclosure can be used in a variety of applications that require a conductive polymeric material, such as for transparent antistatic coatings that can be used, for example, in the aeronautics industry.

The conjugated polymer-surfactant complex can be used alone, or as an additive (e.g., in a composite material). In general, when used as an electron conductor in a composite, the proportion of the conjugated polymer-surfactant complex is at or above the electrical percolation threshold. However, a composite having a conjugated polymer- surfactant complex amount of greater than the electrical percolation threshold can provide increased electron transport. In some embodiments, the composite (e.g., a corrosion- reducing composite) includes a conjugated polymer-surfactant complex in an amount of about 1 wt % or more (e.g., about 2 wt % or more, about 5 wt % or more, about 10 wt % or more, about 15 wt % or more about 20 wt % or more, or about 25 wt % or more) and/or about 30 wt % or less (e.g., about 25 wt % or less, about 20 wt % or less, about 15 wt % or less, about 10 wt % or less, about 5 wt % or less, or about 2 wt % or more).

As an example, the conjugated polymer-surfactant complex can be used as an additive in galvanic corrosion-reducing composites, such as a galvanic corrosion- reducing paint ("corrosion-reducing paint"). The corrosion-reducing composite (e.g., the paint) can include the conjugated polymer-surfactant complex and a separate corrosion- reducing material. In such an instance, the conjugated polymer-surfactant complex can serve as a conduit for electron travel and can reduce galvanic corrosion of an underlying substrate by shuttling electrons to a sacrificial corrosion-reducing material, such as magnesium, zinc, aluminum, and alloys thereof. The sacrificial corrosion-reducing material can be in the form of fine particles (e.g., a powder). Without wishing to be bound by theory, it is believed that a proportion of conjugated polymer-surfactant complex in a corrosion-reducing composite is directly related to the corrosion-reducing capacity of the composite.

In some embodiments, the corrosion-reducing composite (e.g., a paint) includes a sacrificial corrosion-reducing material in an amount of less than 50 wt % (e.g., less than 40 wt %, less than 30 wt %, less than 20 wt %, less than 10 wt %, or less than 5 wt %). The amount of sacrificial corrosion-reducing material can vary depending on an amount of corrosion reduction that is desired. In some embodiments, the conjugated polymer- surfactant complex is effective for reducing galvanic corrosion of an underlying metallic substrate, even in the absence of sacrificial corrosion-reducing materials in a corrosion- reducing composite.

The corrosion-reducing composite, when in the form of a paint, can include other components such as binders (e.g., synthetic or natural resins), solvent, polymers (e.g., acrylic polymers, vinyl acrylic polymers, styrene acrylic polymers, etc.), pigments, fillers, and additives such as catalysts, thickeners, stabilizers, emulsifiers, texturizers, adhesion promoters, UV stabilizers, flatteners (de-glossing agents), biocides, etc. In some embodiments, to modify a viscosity of a corrosion-reducing paint including the conjugated polymer-surfactant complex, a solvent can be added, e.g., in an amount of less than 10 wt %.

The corrosion reducing capability of a composite containing a conjugated polymer-surfactant complex can be determined using a "C" value, as described in Example 2, below. For example, a paint containing about 6 wt % of a conjugated polymer-surfactant complex can improve corrosion-resistance of an underlying substrate by at least about 55%, compared to a paint that does not include the conjugated polymer- surfactant complex. As another example, a paint containing about 6 wt % of a conjugated polymer-surfactant complex and 30 wt % zinc powder can improve corrosion resistance of an underlying substrate by at least about 60%, compared to a paint that does not include the conjugated polymer-surfactant complex. In some embodiments, a weight percent of 0.5 wt % to 49 wt % of a conjugated polymer-surfactant complex can increase the corrosion resistance by 10 % to 10,000 % (e.g., by 50 % to 5,000 %, by 50 % to 1,000 %, by 50 to 500 %, or by 50 % to 200 %) compared to a composite that does not include the complex.

In some embodiments, the conjugated polymer-surfactant complex is incorporated into a battery, where it can serve as a polymeric electrolyte and/or as an electrode. When used as a polymeric electrolyte, the conjugated polymer-surfactant complex can serve as a matrix that can hold electrochemically active species in the battery. In some embodiments, the conjugated polymer-surfactant complex is a current collector in a battery. The conjugated polymer-surfactant complex can shuttle electrons within a battery by transporting charge from an electrochemically active species to another.

The following examples are included for the purpose of illustrating, not limiting, the described embodiments.

EXAMPLES

Example 1. Preparation and Characterization of Representative Conjugated polymers

In this example, the preparation, characterization, and use of representative conjugated polymer-surfactant complexes of the disclosure are described. Metal-surfactant salt synthesis

Metal chlorides (FeCl₃, VC1₃, and AICI3), sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and dioctyl sodium sulfosuccinate were purchased from Sigma Aldrich and used as received.

Generally, a known quantity of surfactant was dispersed in water (normally -5-10 g/L). In a separate vessel, metal chloride is dissolved in water. A 3: 1 surfactan metal molar ratio was maintained. An excess of metallic chloride was used in order to decrease the number of unreacted surfactant molecules. The metallic chloride solution was slowly added to the surfactant dispersion while vigorously stirring to form a metal-surfactant salt. The solid metallic salt was separated from the liquid phase by filtration. The filtrate was washed with water. The salt was then dried. The color of the resulting products varied with the metal and surfactant used. Iron-surfactant salts had an orange hue (except for yellow Fe-DS salt). Vanadium-surfactant salts result in a dark green salt. Aluminum- surfactant salts were white.

PEDOT-surfactant complex synthesis

Iron-surfactant salts, as synthesized above, were used to synthesize poly(ethylene dioxythiophene) (PEDOT). In general, a given iron-surfactant salt was dissolved in toluene, methanol, isopropyl alcohol, or chloroform. A monomer, such as ethylene dioxythiophene monomer (EDOT) (Sigma- Aldrich), was added to the iron salt dispersion in a molar ratio of 1 : 1 relative to iron. The mixture was thoroughly mixed and reacted, and left undisturbed for at least a week. After enough time has passed for formation of a PEDOT-surfactant complex to take place, the PEDOT-surfactant complex was purified by centrifugation at 1200 rpm for 20 minutes. The PEDOT-surfactant complex formed a pellet at the bottom of the centrifugation vial, while the iron-surfactant salt stayed dispersed in the supernatant. The solvent was removed after each centrifugation step and replaced with fresh solvent. The polymer-surfactant complex was dispersed by vortexing. These steps were repeated until the absorbance peak of the salt was not observed any more ( around ten times). The PEDOT-surfactant complex was dispersed one last time by sonication, and the concentration of the polymer in solution was calculated from thermal gravimetric measurements.

Referring to FIGURE 6, the stabilities of various PEDOT-surfactant syntheses using different surfactant-solvent pairs, after the syntheses were carried out for 1 week (or for 1 or 2 weeks for 2-ethyl-hexylsulfate), is shown. Surfactants such as dioctyl sulfosuccinate (AOT) and dodecylbenzene sulfonate (DBS) were dispersible and polymerize EDOT in different solvents such as toluene, chloroform, and methanol. Other dopants such as dodecyl sulfate (DS), octyl sulfonate (OS), and 2-ethyl-hexylsulfate were dispersible in alcohols so the PEDOT-surfactant synthesis was performed in methanol. FIGURE 6 indicates that syntheses performed in methanol resulted in more stable polymer dispersions. However, the low yields obtained compared to the syntheses in other solvents suggested slower synthesis kinetics. This could be due to the low solubility of the monomer EDOT in the alcohol due to the high polarity of the solvent. In chloroform and toluene EDOT disperses readily, resulting in faster reaction kinetics in those solvents.

Conjugated polymer-surfactant complex structure

The conformations of the colloidal polymer particles formed by the conjugated polymer-surfactant complexes changed depending on the surfactant selection. FIGURES 7A-7D show sTEM micrographs of PEDOT doped with DS, AOT, and DBS. The structure of the polymer domain changes from independent spheres in the case of DS (FIGURE 7A), to an interconnected network when AOT is used (FIGURE 7B), to ellipsoidal plates for DBS (FIGURES 7C and 7D). Similar structures are achieved when using the same dopant molecule in different solvents. FIGURES 7C and 7D show PEDOT-DBS dispersions in toluene and methanol, and the presence of the similar plate structures was observed in both samples. These structures were seen when the sample contained a low PEDOT loading (2-5 mg/ml) and the excess iron salt was kept in the dispersion. The excess salt and the low concentrations stabilized the solvent into these defined structures. Once the concentration was increased, or the stabilizing salt removed, the conjugated polymer-surfactant complexes started to further aggregate into mesoscopic structures.

It was necessary to purify the PEDOT-surfactant complex because the iron- surfactant salt remaining in the sample accounted for up to 30 wt% of the total sample (up to 80 wt% of the solids). This high concentration of the iron-surfactant salt disrupted the properties of the polymer-surfactant complex and gave the sample a green color (instead of the blue of the PEDOT).

FIGURES 8A-8I show several sTEM micrographs of the three PEDOT: surfactant complexes (DS, AOT and DBS) after the purification steps. The most notable change was the disappearance of the spheres, plates, and network structures that were found in FIGURES 7A-7D. All the samples had amorphous aggregates with high surface areas. There appeared to be structural differences amongst the polymer aggregates formed by the different polymer-dopant complex. PEDOT-DBS (FIGURES 8A-8C) seemed to be formed of large aggregates with sharps edges. In FIGURE 8 A, an aggregate that was around 20-25 μιη long was observed. Some sections of this large aggregate seem to be joined by a sheet-like component of the aggregate (circle in FIGURE 8A). This interconnected, high surface area, large aggregate was desirable for antistatic dissipation applications, since a high interconnectivity of the polymeric domains could be achieved by using a very small polymer loading.

FIGURES 8D-8F show that the polymeric domains found in the PEDOT-AOT complexes were smaller compared to the other two complexes. Furthermore, these smaller polymeric domains did not seem to interact with each other, and were spatially separated from each other. FIGURE 8G-8I show the PEDOT-DS complex, which was also formed by large aggregates with very high surface area. Instead of the presence of sheet structures in FIGURE 8 A, the PEDOT-DS complex showed globular, cloudy structures (circle in FIGURE 8G). Surfactant choice appeared to influence the structural conformation and aggregation of the PEDOT-surfactant domains.

The mesostructure of the PEDOT-surfactant complex aggregates were probed by microscopic techniques. These techniques showed some differences in the structural composition of the different samples, but the nature of these techniques could bias the study due to drying effects and due to focusing the analysis on a small part of the sample instead of the entire volume. Scattering techniques (e.g., small angle neutron scattering, "SANS") could also be used to obtain the overall mesostructure of the bulk sample. Scattering techniques probe the sample in situ, taking away any effects caused by the sample preparations. With SANS, the scattering contrast could be varied by using deuterated solvents, which have a high contrast with the hydrogen in the monomer and dopant units. Additionally, by pairing SANS and ultra-small angle neutron scattering (USANS) it would be possible to probe all the pertinent length scales of the sample. This extended scattering profile would reveal not only the form factor of the structures, but would also give a measurement of the surface area achieved by the different PEDOT- surfactant aggregates.

The specific surface areas of the PEDOT surfactant complexes were obtained from SANS measurements. The PEDOT-DBS complex had a specific surface area of 51.2 m²/g. The PEDOT-AOT complex had a specific surface area of 35.5 m²/g. The PEDOT-DBS complex had a specific surface area of 14.3 m²/g.

Polymer-surfactant complex conductivity

Referring to FIGURES 9A and 9B, the conductivities of a dispersion of PEDOT- DBS complex and a dispersion of PEDOT-AOT complex was measured as a function of the PEDOT-surfactant complex concentrations. The conductivity of the dispersion increased as the PEDOT-surfactant complex concentration increased. Referring to FIGURE 9A, a change in the dependence of the conductivity of PEDOT-DBS in chloroform was observed at about 12 mg/ml (or about 1 wt%), corresponding to the electrical percolation threshold. Referring to FIGURE 9B, a change in the dependence of the conductivity of PEDOT-AOT in chloroform was observed at about 4 mg/ml (or about 0.12 wt%), corresponding to the electrical percolation threshold. This inflexion point in each of FIGURES 9A and 9B corresponded to the concentration at which the PEDOT- DBS domains or the PEDOT-AOT domains, respectively, started forming a percolating path between the two electrodes. The change in slope indicates that the conductivity arose from two different mechanisms. The first was due to the higher number of carriers freely moving in solution. Whereas the second slope (steeper slope) was caused by the formation of conduction pathways by the overlapping PEDOT-DBS or PEDOT-AOT domains.

Use of the PEDOT-surfactant complexes

A poly(lactic acid)-(PEDOT-DBS) composite was prepared by dissolving 478 mg of poly(lactic acid) in chloroform, and then mixing it with 10 ml of a 30 mg/ml PEDOT- DBS dispersion in chloroform. The solvent was then evaporated by vacuum, resulting in a solid, visually opaque, blue film.

Thus, a PEDOT-surfactant complex could form a dispersion, a gel, and be readily incorporated into composite materials.

Example 2. Representative Conjugated Polymer-Surfactant Complexes as Anticorrosion

Additives

In this example, the use of representative conjugated polymer-surfactant complexes of the disclosure as anticorrosion additives are described. Accelerated Corrosion Test & Analysis Methods

A brine immersion method was used to accelerate the corrosion of carbon steel. Steel coupons (3" x V₂" ^x V₈") with rounded edges were cleaned in isopropanol before dip-coating in pure and additive-loaded Sherwin-Williams Industrial Enamel (B54 Series). All additives (dry powders) were dispersed in the paint using a high shear mixer and allowed to dry at room temperature and humidity for at least 4 days. The average coating thickness varied with the additive loading level (3 - 12 mil). After drying, the coatings were scribed once at a length of ½" according to ASTM D 1654-08.

The coated steel coupon was then submerged to a level of 1/2 the scribe length in a stirred 1 M NaCl solution. A potential of 2.4V was applied to the coupon, with a submerged high surface area platinum counter-electrode, for 60 minutes. The corroded coupons were then submerged into a toluene bath to strip the paint and view the underlying corrosion.

The corrosion was evaluated according to ASTM D 1654-08 where the width of the corrosion zone (c_w) can be compared between samples using the following equation:

2

where c_s is the width of the scribe and C is the adjusted corrosion zone. This method provided a quantitative comparison of the corrosion of steel with different coatings. A diagram of a typical analysis (c_w and c_s valued) is shown in FIGURE 10.

One limitation of this method was that it preferred corrosion that occurred along the width of the scribe, underneath the coating, and did not factor in the depth of the corrosion zone.

Polyp yrrole-DBS

A polypyrrole-DBS ("PPy-DBS") dry powder was synthesized according to the general synthetic procedure of Example 1 for PEDOT-DBS, but with pyrrole as a starting material. Fe(III)-dodecylbenzenesulfonate salt and toluene were used in the synthetic reaction. The PPy-DBS was isolated and dried in air.

Referring to FIGURE 1 1 , the conductivity of a dispersion of PPy-DBS complex in toluene was measured as a function of PPy-DBS complex concentration. The conductivity of the dispersion increased as the PPy-DBS complex concentration increased. Referring to FIGURE 1 1 , a change in the dependence of the conductivity of PPy-DBS in toluene was observed at about 11 mg/ml (or about 2 wt%), corresponding to the electrical percolation threshold.

Corrosion testing results

A series of pure and additive loaded paints were used to evaluate the corrosion inhibition potential. Zinc-rich primers are the industry standard for active corrosion protection. Therefore, both 30 wt% Zn and 90 wt% Zn in paint were tested under accelerated conditions. These were compared to the protection provided by pure paint and there is a clear trend towards enhanced protection with increasing zinc content, as shown in FIGURES 12A-12C. The corrosion of each representative coupon was shown twice, once immediately after paint stripping (left) and the other 1 day after stripping with red clay added to highlight the corrosion depth (right).

To provide substantial corrosion protection, the zinc dust must percolate from the steel to the outer surface of the coating. This meant that low zinc loadings (such as 30 wt% Zn) were typically ineffective at providing sustained corrosion protection because the zinc dust was not percolated; instead it was more likely to form isolated "islands". If an island was not electrically connected to the steel, it could not be used to provide corrosion protection.

Paint samples were prepared with addition of a polypyrrole-DBS ("PPy-DBS") complex. To prepare the paint samples, a PPy-DBS dry powder (PPy-DBS synthesized using pyrrole, Fe(III)-dodecylbenzenesulfonate salt in toluene according to the general procedure of Example 1, then dried) was added to a paint (i.e., a paint without added Zn, a paint with 30 wt% Zn, and a paint with 90 wt% Zn). The mixture was stirred using a high shear mixer at 1000 RPM. A paint coating on a carbon steel coupon was applied by dip coating carbon steel into the paint and allowing the coupon to dry for 5 days.

A PPy-DBS complex loading of greater than 2 wt% allowed for electrical contact between the steel and the outer surface of the paint. Referring to FIGURE 13 A, when combined with zinc dust, the polypyrrole-DBS complex 200 (shown as lines interconnecting the zinc particles) removed the "island effect" and allowed all of the zinc 210 to provide corrosion protection even at lower total zinc loadings. These results are shown in the accelerated corrosion testing shown in FIGURE 13B, which compared the previous zinc coatings with a 6 wt% polypyrrole-DBS complex + 30 wt% Zn in paint. Referring to FIGURE 13B, the carbon steel coupon on the left showed a piece of carbon steel that was painted and then scribed to allow corrosion to occur at the scribe. The carbon steel coupon on the right shows the same couple one day later, showing flash rust around the scribe, with red putty put into the corrosion zone to highlight the corroded metal during the corrosion experiment.

The PPy-DBS complex can also provide direct corrosion protection without the use of zinc, as shown in FIGURE 14.

Thus, a polypyrrole-DBS complex could provide effective electron shuttling between the zinc dust particles and enhance corrosion resistance of metal substrates.

Example 3. Viscosity Characteristics of Representative Conjugated Polymer-Surfactant

Complexes

In this example, the viscosity characteristics of representative conjugated polymer-surfactant complexes of the disclosure, when incorporated into paints, are described.

Paint Viscosity Measurements

The viscosities of pure and additive loaded paints of Example 2 were measured over a shear rate ramp. Viscosities were measured using a cone-plate geometry in a stress-controlled rheometer. A shear sweep was performed and the stress (converted to viscosity) was reported as a function of shear rate. Referring to FIGURE 15, all paints were shear-thinning. Polypyrrole-DBS complex-loaded paints, which showed corrosion inhibition potential similar to that of zinc-rich paint, had lower viscosities than the zinc- rich paint across most shear rates that were probed.

While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Claims

CLAIMS The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A conjugated polymer-surfactant complex comprising an electrical percolation threshold of less than about 10 wt % when the conjugated polymer-surfactant complex is incorporated into a non-conducting matrix, wherein the conjugated polymer- surfactant complex comprises a conjugated polymer and a surfactant associated with the conjugated polymer, wherein the surfactant is selected from the group consisting of a C₆-

C₁₆ alkyl sulfonate, a C₆-C₁₆ alkyl sulfate, a C₆-C₁₆ alkylbenzenesulfonate, and any combination thereof.

2. The conjugated polymer- surfactant complex of claim 1, wherein the conjugated polymer is selected from the group consisting of poly(3,4- ethylenedioxythiophene), polypyrrole, polythiophene, polyaniline, and substituted derivatives thereof.

3. The conjugated polymer-surfactant complex of claim 1, wherein the conjugated polymer is poly(3,4-ethylenedioxythiophene).

4. The conjugated polymer- surfactant complex of claim 1, wherein the surfactant is selected from the group consisting of dodecyl sulfate, branched octyl sulfate, hexadecyl sulfate, dodecylbenzene sulfonate, dioctyl sulfosuccinate, naphthalene sulfonates, Cg-C^ alkyl sulfonates such as hexyl sulfonate and octyl sulfonate

5. The conjugated polymer-surfactant complex of claim 1, wherein the conjugated polymer is associated with the surfactant at a ratio of less than one surfactant per every two repeat units.

6. The conjugated polymer- surfactant complex of claim 1, wherein the conjugated polymer-surfactant complex remains dispersed in a solution over a period of at least two weeks.

7. The conjugated polymer-surfactant complex of claim 6, wherein the solution comprises an organic solvent selected from the group consisting of alcohol, toluene, xylenes, chlorobenzene, chloroform, hexane, and cyclohexane.

8. The conjugated polymer- surfactant complex of claim 1, wherein the conjugated polymer-surfactant complex is in the form of a gel.

9. The conjugated polymer- surfactant complex of claim 1, wherein the conjugated polymer-surfactant complex has a specific surface area of at least 10 m²/g.

10. The conjugated polymer-surfactant complex of claim 1, wherein the nonconducting matrix is selected from the group consisting of a non-conducting polymer and a paint.

11. The conjugated polymer-surfactant complex of claim 10, wherein the nonconducting polymer is selected from the group consisting of polyurethanes, polysiloxanes, epoxies, uv-curable resins, polylactic acid, poly(methyl methacrylate), polyethylene, polypropylene, polyethylene terephthalate.

12. A corrosion-reducing composite, comprising the conjugated polymer- surfactant complex of claim 1 and a corrosion-reducing material.

13. The composite of claim 12, wherein the corrosion-reducing material is selected from the group consisting of magnesium, zinc, aluminum, and alloys thereof.

14. The composite of claim 12, wherein the corrosion-resistant material is in the form of a powder.

15. A battery comprising the conjugated polymer-surfactant complex of claim

1.

16. The battery of claim 15, comprising a polymeric electrolyte comprising the conjugated polymer-surfactant complex.

17. The battery of claim 15, comprising a polymeric electrode comprising the conjugated polymer-surfactant complex.

18. A process of making a conjugated polymer- surfactant complex, comprising:

(a) providing a mixture, comprising:

(i) an organic solvent; (ii) a surfactant selected from the group consisting of a Cg-C^ alkyl sulfonate, a Cg-C^ alkyl sulfate, a Cg-C^ alkylbenzenesulfonate, and any combination thereof;

(iii) a transition metal cation; and

(iv) a monomer selected from the group consisting of 3,4- ethylenedioxythiophene, thiophene, pyrrole, aniline, and substituted derivatives thereof; and

(b) reacting the mixture to provide a conjugated polymer-surfactant complex comprising a conjugated polymer comprising 3,4-ethylenedioxythiophene, thiophene, pyrrole, or any combination thereof, wherein the conjugated polymer-surfactant complex has an electrical percolation threshold of less than about 10 wt % when the conjugated polymer-surfactant complex is incorporated into a non-conducting matrix,

wherein the conjugated polymer-surfactant complex comprises a conjugated polymer and a surfactant associated with the conjugated polymer, wherein the surfactant is selected from the group consisting of a C₆-C₁₆ alkyl sulfonate, a C₆-C₁₆ alkyl sulfate, a Cg-C^ alkylbenzenesulfonate, and any combination thereof.

19. The process of claim 18, wherein the transition metal is selected from the group consisting of iron (III), V(III), and Au(III).

20. The process of claim 18, wherein the surfactant is selected from the group consisting of dodecyl sulfate, branched octyl sulfate, hexadecyl sulfate, dodecylbenzene sulfonate, dioctyl sulfosuccinate, naphthalene sulfonates, Cg-C^ alkyl sulfonates such as hexyl sulfonate and octyl sulfonate.

21. The process of claim 18, wherein the organic solvent is selected from the group consisting of alcohol, toluene, xylenes, chlorobenzene, chloroform, hexane, and cyclohexane.

22. The process of claim 18, wherein when the organic solvent is methanol, the surfactant is dodecylsulfate or dodecylbenzenesulfonate, and the monomer is 3,4- ethylenedioxythiophene, pyrrole, or substituted derivatives thereof.

23. The process of claim 22, wherein when the organic solvent is methanol and the surfactant is dodecylsulfate, the monomer concentration is 0.5-1 mg/ml and the monomer to transition metal cation mole fraction is 1.

24. The process of claim 22, wherein when the organic solvent is methanol and the surfactant is dodecylbenzenesulfonate, the monomer concentration is 2 mg/ml and the monomer to transition metal cation mole fraction is 1.

25. The process of claim 18, wherein when the organic solvent is chloroform, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4- ethylenedioxythiophene, pyrrole, or substituted derivatives thereof.

26. The process of claim 25, wherein when the organic solvent is chloroform and the surfactant is dodecylbenzenesulfonate, the monomer concentration is 0.5 mg/ml and the monomer to transition metal cation mole fraction is 0.2; the monomer concentration is 1 mg/ml and the monomer to transition metal cation mole fraction is 0.5; the monomer concentration is 2 mg/ml and the monomer to transition metal cation mole fraction is 2; the monomer concentration is 5-10 mg/ml and the monomer to transition metal cation mole fraction is 2; the monomer concentration is 20 mg/ml and the monomer to transition metal cation mole fraction is 5; or the monomer concentration is 30 mg/ml and the monomer to transition metal cation mole fraction is 10; or the monomer concentration is 50 mg/ml and the monomer to transition metal cation mole fraction is 20.

27. The process of claim 18, wherein when the organic solvent is toluene and the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4- ethylenedioxythiophene, pyrrole, or substituted derivatives thereof, the monomer concentration is 0.5 mg/ml and the monomer to transition metal cation mole fraction is 1- 5; the monomer concentration is 0.5-1 mg/ml and the monomer to transition metal cation mole fraction is 2-5; or the monomer concentration is 1 mg/ml and the monomer to transition metal cation mole fraction is 2-5.

28. The process of any one of claims 22-27, wherein the conjugated polymer- surfactant complex remains dispersed in a solution over a period of at least two weeks.

29. The process of claim 18, wherein when the organic solvent is chloroform, the surfactant is dodecylbenzenesulfonate, pyrrole, or substituted derivatives thereof, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, or substituted derivatives thereof, and

the monomer concentration is 2 mg/ml and the monomer to transition metal cation mole fraction is 0.2, the monomer concentration is 3-7 mg/ml and the monomer to transition metal cation mole fraction is 0.2-0.3, the monomer concentration is 4-7 mg/ml and the monomer to transition metal cation mole fraction is 0.2-0.5; the monomer concentration is 7 mg/ml and the monomer to transition metal cation mole fraction is 0.2- 1, the monomer concentration is 7-50 mg/ml and the monomer to transition metal cation mole fraction is 1, the monomer concentration is 20-50 mg/ml and the monomer to transition metal cation mole fraction is 1-2, the monomer concentration is 30-50 mg/ml and the monomer to transition metal cation mole fraction is 1-5, or the monomer concentration is 50 mg/ml and the monomer to transition metal cation mole fraction is 1- 10.

30. The process of claim 18, wherein when the organic solvent is toluene, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, or substituted derivatives thereof, and

the monomer concentration is 0.5 mg/ml and the monomer to transition metal cation mole fraction is 0.5-0.75, the monomer concentration is 0.5-5 mg/ml and the monomer to transition metal cation mole fraction is 0.5, the monomer concentration is 2- 5 mg/ml and the monomer to transition metal cation mole fraction is 0.5-2, the monomer concentration is 4-5 mg/ml and the monomer to transition metal cation mole fraction is 0.5-5.

31. The process of claim 18, wherein when the organic solvent is hexanes, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, or substituted derivatives thereof, and

the monomer concentration is 0.5-5 mg/ml and the monomer to transition metal cation mole fraction is 1.

32. The process of claim 18, wherein when the organic solvent is hexanes, the surfactant is dodecylbenzenesulfonate, and the monomer is 3,4-ethylenedioxythiophene, pyrrole, or substituted derivatives thereof, and

the monomer concentration is 1-5 mg/ml and the monomer to transition metal cation mole fraction is 1.

33. The process of any one of claims 29-32, wherein the conjugated polymer- surfactant complex is a gel.